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Cristina CASTAGNETTI

Professore Associato
Dipartimento di Ingegneria "Enzo Ferrari"

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Pubblicazioni

2023 - Quantifying the Loss of Coral from a Bleaching Event Using Underwater Photogrammetry and AI-Assisted Image Segmentation [Articolo su rivista]
Kopecky, K. L.; Pavoni, G.; Nocerino, E.; Brooks, A. J.; Corsini, M.; Menna, F.; Gallagher, J. P.; Capra, A.; Castagnetti, C.; Rossi, P.; Gruen, A.; Neyer, F.; Muntoni, A.; Ponchio, F.; Cignoni, P.; Troyer, M.; Holbrook, S. J.; Schmitt, R. J.
abstract

Detecting the impacts of natural and anthropogenic disturbances that cause declines in organisms or changes in community composition has long been a focus of ecology. However, a tradeoff often exists between the spatial extent over which relevant data can be collected, and the resolution of those data. Recent advances in underwater photogrammetry, as well as computer vision and machine learning tools that employ artificial intelligence (AI), offer potential solutions with which to resolve this tradeoff. Here, we coupled a rigorous photogrammetric survey method with novel AI-assisted image segmentation software in order to quantify the impact of a coral bleaching event on a tropical reef, both at an ecologically meaningful spatial scale and with high spatial resolution. In addition to outlining our workflow, we highlight three key results: (1) dramatic changes in the three-dimensional surface areas of live and dead coral, as well as the ratio of live to dead colonies before and after bleaching; (2) a size-dependent pattern of mortality in bleached corals, where the largest corals were disproportionately affected, and (3) a significantly greater decline in the surface area of live coral, as revealed by our approximation of the 3D shape compared to the more standard planar area (2D) approach. The technique of photogrammetry allows us to turn 2D images into approximate 3D models in a flexible and efficient way. Increasing the resolution, accuracy, spatial extent, and efficiency with which we can quantify effects of disturbances will improve our ability to understand the ecological consequences that cascade from small to large scales, as well as allow more informed decisions to be made regarding the mitigation of undesired impacts.

2022 - Image-Based Monitoring of Cracks: Effectiveness Analysis of an Open-Source Machine Learning-Assisted Procedure [Articolo su rivista]
Parente, Luigi; Falvo, Eugenia; Castagnetti, Cristina; Grassi, Francesca; Mancini, Francesco; Rossi, Paolo; Capra, Alessandro
abstract

The proper inspection of a cracks pattern over time is a critical diagnosis step to provide a thorough knowledge of the health state of a structure. When monitoring cracks propagating on a planar surface, adopting a single-image-based approach is a more convenient (costly and logistically) solution compared to subjective operators-based solutions. Machine learning (ML)- based monitoring solutions offer the advantage of automation in crack detection; however, complex and time-consuming training must be carried out. This study presents a simple and automated ML-based crack monitoring approach implemented in open sources software that only requires a single image for training. The effectiveness of the approach is assessed conducting work in controlled and real case study sites. For both sites, the generated outputs are significant in terms of accuracy (~1 mm), repeatability (sub-mm) and precision (sub-pixel). The presented results highlight that the successful detection of cracks is achievable with only a straightforward ML-based training procedure conducted on only a single image of the multi-temporal sequence. Furthermore, the use of an innovative camera kit allowed exploiting automated acquisition and transmission fundamental for Internet of Things (IoTs) for structural health monitoring and to reduce user-based operations and increase safety.

2022 - PHOTOGRAMMETRIC AND FLUORESCENCE SOLUTIONS FOR MONITORING OF HABITAT FORMING ORGANISMS [Relazione in Atti di Convegno]
Rossi, P.; Righi, S.; Parente, L.; Castagnetti, C.; Cattini, S.; Di Loro, G.; Falvo, E.; Grassi, F.; Mancini, F.; Rovati, L.; Simonini, R.; Capra, A.
abstract

The development and testing of innovative technologies and automated data analysis methodologies offer tools for the monitoring of complex marine ecosystems and the direct and indirect effects of climate change on natural heritage. Photogrammetric methods allow precise mapping of the underwater landscape as well as detailed three-dimensional (3D) reconstruction of marine structures, improving the study of complex marine ecosystems. Moreover, fluorescence analyses can provide critical information about the health status of marine organisms. Analysing the variations in their self-fluorescence, allow for early detect changes in their physiological state. These applications provide very useful data to evaluate the health state of biodiversity-rich 3D biogenic structures and make measurements of fine-scale changes, with greater precision than existing methodologies. This contribution shows a multidisciplinary approach to the design, development, and implementation of a technological solution based on the above-mentioned optical measuring systems. Such a system is characterized by a reflex camera, LED-based light sources, and filters to allow the analysis of the self-fluorescence signal. The proposed solution aspires to improve the standardization of monitoring plans through non-destructive fine-scale accurate data collection for image analysis and multi-temporal comparisons, providing challenging stepping-stones for habitat-forming anthozoan management and restoration activities. Initial results of tests carried out in controlled conditions are shown. The photogrammetric approach resulted in 3D reconstructions that allow the monitoring of deformations at millimetre scale. The fluorimetry methodology allowed to obtain high-resolution images with great repeatability, which enabled the identification of stressful status even in absence of geometric deformations. The proposed approaches and obtained results are discussed, together with potential issues related to their implementation in a real-world context adopting remotely operative vehicles.

2021 - Needs and gaps in optical underwater technologies and methods for the investigation of marine animal forest 3D-structural complexity [Articolo su rivista]
Rossi, Paolo; Ponti, Massimo; Righi, Sara; Castagnetti, Cristina; Simonini, Roberto; Mancini, Francesco; Agrafiotis, Panagiotis; Bassani, Leonardo; Bruno, Fabio; Cerrano, Carlo; Cignoni, Paolo; Corsini, Massimiliano; Drap, Pierre; Dubbini, Marco; Garrabou, Joaquim; Gori, Andrea; Gracias, Nuno; Ledoux, Jean-Baptiste; Linares, Cristina; Pulido Mantas, Torcuato; Menna, Fabio; Nocerino, Erica; Palma, Marco; Pavoni, Gaia; Ridolfi, Alessandro; Rossi, Sergio; Skarlatos, Dimitrios; Treibitz, Tali; Turicchia, Eva; Yuval, Matan; Capra, Alessandro
abstract

Marine animal forests are benthic communities dominated by sessile suspension feeders (such as sponges, corals, and bivalves) able to generate three-dimensional (3D) frameworks with high structural complexity. The biodiversity and functioning of marine animal forests are strictly related to their 3D complexity. The present paper aims at providing new perspectives in underwater optical surveys. Starting from the current gaps in data collection and analysis that critically limit the study and conservation of marine animal forests, we discuss the main technological and methodological needs for the investigation of their 3D structural complexity at different spatial and temporal scales. Despite recent technological advances, it seems that several issues in data acquisition and processing need to be solved, to properly map the different benthic habitats in which marine animal forests are present, their health status and to measure structural complexity. Proper precision and accuracy should be chosen and assured in relation to the biological and ecological processes investigated. Besides, standardized methods and protocols are strictly necessary to meet the FAIR (findability, accessibility, interoperability, and reusability) data principles for the stewardship of habitat mapping and biodiversity, biomass, and growth data.

2020 - Coral Reef Monitoring by Scuba Divers Using Underwater Photogrammetry and Geodetic Surveying [Articolo su rivista]
Nocerino, Erica; Menna, Fabio; Gruen, Armin; Troyer, Matthias; Capra, Alessandro; Castagnetti, Cristina; Rossi, Paolo; Brooks, Andrew J.; Schmitt, Russell J.; Holbrook, Sally J.
abstract

Underwater photogrammetry is increasingly being used by marine ecologists because of its ability to produce accurate, spatially detailed, non-destructive measurements of benthic communities, coupled with affordability and ease of use. However, independent quality control, rigorous imaging system set-up, optimal geometry design and a strict modeling of the imaging process are essential to achieving a high degree of measurable accuracy and resolution. If a proper photogrammetric approach that enables the formal description of the propagation of measurement error and modeling uncertainties is not undertaken, statements regarding the statistical significance of the results are limited. In this paper, we tackle these critical topics, based on the experience gained in the Moorea Island Digital Ecosystem Avatar (IDEA) project, where we have developed a rigorous underwater photogrammetric pipeline for coral reef monitoring and change detection. Here, we discuss the need for a permanent, underwater geodetic network, which serves to define a temporally stable reference datum and a check for the time series of photogrammetrically derived three-dimensional (3D) models of the reef structure. We present a methodology to evaluate the suitability of several underwater camera systems for photogrammetric and multi-temporal monitoring purposes and stress the importance of camera network geometry to minimize the deformations of photogrammetrically derived 3D reef models. Finally, we incorporate the measurement and modeling uncertainties of the full photogrammetric process into a simple and flexible framework for detecting statistically significant changes among a time series of models.

2020 - Detecting change in coral reef 3D structure using underwater photogrammetry: critical issues and performance metrics [Articolo su rivista]
Rossi, P.; Castagnetti, C.; Capra, A.; Brooks, A. J.; Mancini, F.
abstract

This paper presents a multi-temporal underwater photogrammetric survey of a reef patch located in Moorea, French Polynesia, designed to detect a coral growth of 10–15 mm/year. Structure-from-Motion photogrammetry and underwater imagery allows the three-dimensional quantification of reef structural complexity and ecologically relevant characteristics at the patch scale. A high degree of accuracy and fine resolution are required in order to guarantee the repeatability of surveys over time within the same reference system, meaning a proper geodetic network and acquisition scheme are mandatory. Measuring tools and reference points were properly designed in order to constrain the photogrammetric reconstruction. The network adjustment, performed with distance and height difference observations, provided an average accuracy of ± 1.2 mm and ± 2.9 mm in the horizontal and vertical components, respectively. The final accuracies of photogrammetric reconstructions are on the order of 1 cm and few millimeters for the 2017 and 2018 monitoring campaigns, respectively. This results in realized errors in the comparison of about ± 1 cm. Coordinate variations larger than this magnitude can be reasonably interpreted as coral growth or dissolution. The direct comparison of the two subsequent point clouds is effective in order to evaluate trends in growth and perform morphometric analyses. For highly accurate quantitative assessment of local changes, an expert operator can create and analyze specific 2D profiles that are easily produced from the point clouds.

2020 - Underwater Photogrammetry for Change Detection [Relazione in Atti di Convegno]
Capra, Alessandro; Castagnetti, Cristina; Mancini, Francesco; Rossi, Paolo
abstract

2019 - A new methodological approach to assess the stability of discontinuous rocky cliffs using in-situ surveys supported by UAV-based techniques and 3D finite element model: a case study [Articolo su rivista]
Fazio, N. L.; Perrotti, M.; Andriani, G. F.; Mancini, F.; Rossi, P.; Castagnetti, C.; Lollino, P
abstract

This paper aims to present a new methodological approach for the stability assessment of coastal cliffs constituted of discontinuous rock masses. The method entails in situ specific geostructural and geomechanical surveys, three-dimensional UAV-based Photogrammetric structural models, laboratory geotechnical tests and, two- and three-dimensional finite element analysis (FEM). The application of the method to a case study is then presented and discussed; it regards a 600 m long sea rocky cliff located at Sant'Andrea (Melendugno, South of Apulia, SE Italy) and faced to the southern Adriatic Sea. Here the cliff is made up of an about 15 m-thick sequence of laminate calcisiltites alternate with bioturbated calcarenites belonging to the Uggiano la Chiesa Fm. (Middle-Upper Pliocene). The structural discontinuities detected with photogrammetry techniques were compared and validated with those derived from conventional in situ survey methods. Later on, the paper discusses assumptions and results of two- and three-dimensional finite element models developed to investigate the potential failure mechanisms of the sea cliff accounting for pre-existing weak planes or discontinuities with unfavourable orientation. The failure mechanisms obtained by both FEM analysis agree well with those typically observed in the study area.

2019 - COMPARISON of DIVER-OPERATED UNDERWATER PHOTOGRAMMETRIC SYSTEMS for CORAL REEF MONITORING [Relazione in Atti di Convegno]
Nocerino, E; Neyer, F; Gruen, A; Troyer, M; Menna, F; Brooks, A; Capra, A; Castagnetti, C; Rossi, Paolo
abstract

Underwater photogrammetry is a well-established technique for measuring and modelling the subaquatic environment in fields ranging from archaeology to marine ecology. While for simple tasks the acquisition and processing of images have become straightforward, applications requiring relative accuracy better then 1:1000 are still considered challenging. This study focuses on the metric evaluation of different off-the-shelf camera systems for making high resolution and high accuracy measurements of coral reefs monitoring through time, where the variations to be measured are in the range of a few centimeters per year. High quality and low-cost systems (reflex and mirrorless vs action cameras, i.e. GoPro) with multiple lenses (prime and zoom), different fields of views (from fisheye to moderate wide angle), pressure housing materials and lens ports (dome and flat) are compared. Tests are repeated at different camera to object distances to investigate distance dependent induced errors and assess the accuracy of the photogrammetrically derived models. An extensive statistical analysis of the different systems is performed and comparisons against reference control point measured through a high precision underwater geodetic network are reported.

2019 - Dynamic Assessment of Masonry Towers Based on Terrestrial Radar Interferometer and Accelerometers [Articolo su rivista]
Castagnetti, Cristina; Bassoli, Elisa; Vincenzi, Loris; Mancini, Francesco
abstract

This paper discusses the performance of a terrestrial radar interferometer for the structural monitoring of ancient masonry towers. High-speed radar interferometry is an innovative and powerful remote sensing technique for the dynamic monitoring of large structures since it is contactless, non-destructive, and able to measure fast displacements on the order of tenths of millimeters. This methodology was tested on a masonry tower of great historical interest, the Saint Prospero bell tower (Northern Italy). To evaluate the quality of the results, data collected from the interferometer were compared and validated with those provided by two types of accelerometer-based measuring systems directly installed on the tower. Dynamic tests were conducted in operational conditions as well as during a bell concert. The first aimed at characterizing the dynamic behavior of the tower, while the second allowed to evaluate the bell swinging effects. Results showed a good agreement among the different measuring systems and demonstrated the potential of the radar interferometry for the dynamic monitoring of structures, with special focus on the need for an accurate design of the geometric aspects of the surveys.

2019 - Dynamic monitoring and evaluation of bell ringing effects for the structural assessment of a masonry bell tower [Articolo su rivista]
Vincenzi, L; Bassoli, E; Ponsi, Federico; Castagnetti, C; Mancini, F
abstract

The paper presents a rational procedure for the structural assessment of bell towers with respect to the dynamic actions induced by the bell ringing, based on structural monitoring and data processing. This methodology is tested on the bell tower of Saint Prospero (Reggio Emilia, Northern Italy), a masonry tower of great historical interest. The procedure includes an accurate geometrical survey for a deep knowledge of the structural geometry, which is the base for the structural modelling. A finite element model of the tower is calibrated with respect to the modal properties evaluated from the structural response measured in operational conditions. The structural response of the tower was also measured during a famous cultural event held in the city centre of Reggio Emilia, when skilled bell ringers played traditional melodies. The tower displacements are evaluated applying a double integration technique and a detrending procedure based on the empirical mode decomposition to the acquired accelerations. To simulate the structural response to the bell ringing, the tower and the bell are modelled as a single degree of freedom system and an unforced and undamped simple pendulum, respectively. For safety assessment purposes, the structural response of the tower is evaluated considering different oscillation angles in order to identify the one causing the maximum displacement. Finally, the stress pattern of the masonry caused by the bell-induced displacement is estimated thanks to the calibrated finite element model of the tower. Results show that the bell ringing causes a stress pattern lower than the allowable masonry strength for the serviceability conditions.

2019 - High accuracy underwater photogrammetric surveying [Relazione in Atti di Convegno]
Capra, A.; Castagnetti, C.; Dubbini, M.; Gruen, A.; Guo, T.; Mancini, F.; Neyer, F.; Rossi, P.; Troyer, M.
abstract

The evolution of underwater photogrammetry allows to realize 3D models of submerged object and structures throughout the use of rapid and efficient procedures either in terms of data acquisition and data processing. These procedures are based on solutions that are applied using natural control points, signalized markers and tie points; the most common algorithms are based on Structure from Motion (SfM) approach. The limit of these applications is sometimes due to the final accuracy, especially when the goal is a centimeter level of accuracy. This accuracy should be necessary when dealing with a survey devoted to deformation control purposes. An example is the underwater photogrammetry for the determination of coral growth; it is effectively a movement or a deformation detection issue where the geometric change is almost at centimeter or few centimeters accuracy level. When dealing with deformation control applications, a geodetic network is essential to realize a stable and unambiguous reference frame through the accurate and permanent installation of Ground Control Points (GCPs). Such a network, indeed, permits a robust reference frame for the georeferencing of images blocks in the different époques of data acquisition. Therefore, the comparison among subsequent photogrammetric restitutions is based on homogeneous 3D models that have been oriented in the same absolute reference system. The photogrammetric survey is based on a methodological approach especially adapted to underwater biometry (like coral growth determination) and to underwater archaeology. The approach is suitable both for modeling objects of relatively reduced dimensions and for structures with a length of ten meters or more, such as coral barriers, wrecks and long walls. The paper describes underwater photogrammetric surveys on sites at different extensions, the geodetic GCPs reference network installation and measurements (distance and elevation difference observations) as well as preliminary results of the network adjustment. A brief description of image acquisition at a different scales and the resulting 3D model of first campaign are also shown.

2019 - Monitoraggio di strutture storiche mediante interferometria radar terrestre [Relazione in Atti di Convegno]
Bassoli, Elisa; Ponsi, Federico; Castagnetti, Cristina; Mancini, Francesco; Vincenzi, Loris
abstract

In questa memoria vengono discusse le prestazioni, i vantaggi e gli svantaggi dell’interferometria radar terrestre con antenna ad apertura reale (TInRAR) per il monitoraggio strutturale degli edifici esistenti e storici. L’interferometro radar terrestre è in grado di rilevare spostamenti differenziali confrontando la fase del segnale radar raccolto e riflesso dalla struttura rispetto a quella del segnale trasmesso. Gli spostamenti lungo la linea di vista (LoS) che si possono misurare sono dell’ordine del centesimo di millimetro e le misure possono essere campionate con frequenza fino a 200 Hz. La memoria riporta i test dinamici effettuati sulla torre campanaria della Basilica di San Prospero a Reggio Emilia (Italia), confrontando gli spostamenti misurati dal radar terrestre con i valori ottenuti per doppia integrazione delle accelerazioni misurate da accelerometri installati direttamente sulla struttura. Grazie alla capacità di misurare in maniera continua e diretta gli spostamenti di numerosi punti della struttura, l’uso della strumentazione TInRAR integrata alla strumentazione tradizionale potrebbe essere di grande ausilio nell’interpretazione del comportamento strutturale e nella valutazione della progressione di un potenziale danneggiamento nelle strutture a seguito di eventi sismici.

2019 - POTENZIALITÀ E PROBLEMATICHE NELL’UTILIZZO DELLA FOTOGRAMMETRIA SUBACQUEA PER LA MISURA DELL’ACCRESCIMENTO DI COLONIE CORALLIGENE [EVALUATION OF UNDERWATER PHOTOGRAMMETRY’ PERFORMANCES IN THE ASSESSMENT OF CORAL REEF 3D CHANGES] [Articolo su rivista]
Rossi, P.; Castagnetti, C.; Capra, A.; Brooks, A. J.; Mancini, F.
abstract

This paper presents a multi-temporal underwater photogrammetric survey of a reef patch located in Moorea Island (French Polynesia) to detect a coral growth at a required level of accuracy of 10-15 mmyears. An approach based on processing of underwater imagery by the well-known Structure from Motion method and ground control points derived from the adjustment of underwater topographic measurements allowed the three-dimensional quantification of ecological characteristic at patch scale and an assessment of the reef growth and its structural complexity. To guarantee the repeatability of surveys over time at required level of accuracy and spatial resolution, the paper introduces issues related to reference frame, network adjustment and design of photogrammetric surveying. Measuring tools and reference points were properly designed and presented by the authors. The network adjustment performed after measuring distances and height differences, provided an average precision of 1.2 mm and 2.9 mm in the horizontal and vertical component respectively. The final positional precision of photogrammetric reconstructions was in the order of 1 centimeter and few millimeters for 2017 and 2018 monitoring campaigns respectively. Then, the accuracy of the comparison resulted of about 1 cm which represents a factor to be considered in the successive interpretations of coral growth or dissolution phenomena. The direct comparison of the two subsequent point clouds is effective in the evaluation of growth rates and in the successive morphometric analyses. For highly accurate quantitative assessment of local changes, an expert operator can create and analyze specific 2D profiles that easily come from the point clouds.

2019 - WebGIS, 3D modeling and virtual tours to map, record and visualize the cultural, archaeological and landscape heritage: the VisualVersilia project, 3D surveying [Relazione in Atti di Convegno]
Giannini, Martina; Castagnetti, Cristina; Rivola, Riccardo
abstract

This article describes the methodologies and technologies developed during the realization of the WebGIS (Geographic Information System) visualversilia.com, namely a multimedia guide able to map, survey, visualize the rich cultural, archaeological and landscape heritage of Versilia (northwestern Tuscany). It enables users to delve into different temporal settings and to contextualize the local cultural sites within the geographic space of their specific historical periods. The immersive experience is also achieved thanks to the realization of virtual tours and navigable 3D models of archaeological complexes concerning the past and current appearance. This WebGIS is a digital platform, soon available online, for viewing and managing data relative to the cultural sites of Versilia, through their localization on an interactive map with several thematic layers, divided into chronological sub-layers. The aim of the research project is to provide useful information for knowledge, protection and enhancement of the cultural heritage of the area.

2018 - A multidisciplinary approach to document and visualize an archaeological site: The Villa d'Otium of Massaciuccoli (Massarosa, LU) / [Un approccio multidisciplinare per documentare e visualizzare un sito archeologico: La villa d'otium di massaciuccoli (Massarosa, LU)] [Articolo su rivista]
Giannini, M.; Castagnetti, C.
abstract

The research project VisualVersilia 3D aims at offering a new method to record and visualize the territory and its heritage by matching the traditional reading of documents and the potential use of modern communication technologies. The purpose of the project is to define a methodology that can be applied to material culture, as well as to other types of contents and contexts, to enhance the characteristic features of the territory and its heritage. The innovation of the project consists in the development of a procedure for documenting current and past historical times and integrating their 3D visualizations with rendering, capable of returning an immersive virtual reality for a successful enhancement of the heritage. The research implements the methodology in the archaeological complex of Massaciuccoli (Massarosa, LU), one of the best preserved roman site of the Versilia area (Tuscany, Italy). The activities briefly consist in: 1) analysis of all types of available sources; 2) metric three-dimensional survey by laser scanning technology addressed to the structures and buildings of the complex; 3) laser scanning data processing; 4) realization of virtual 3D rendering related to Roman and current condition for documentation and conservation purposes; 5) creation of virtual tour of the site in its current form, on the basis of spherical images then enhanced by texts, and 3D models of the Roman age.

2018 - 3D Reconstruction of rock paintings: a cost-effective approach based on modern photogrammetry for rapidly mapping archaeological findings [Relazione in Atti di Convegno]
Castagnetti, C; Rossi, P; Capra, A
abstract

The work describes a cost-effective methodology for the creation of 3D virtual models with both metric and photo-realistic content developed for archaeologists who need to rapidly map new findings during their field prospections. The potential of modern photogrammetry approach, based on Structure from Motion (SfM) and dense image matching algorithms, coupled with the use of low-cost cameras is evaluated for the creation of 3D models and orthophotos of rock paintings. The case study is located in Brealito valley, in the Calchaqui basin of the Province of Salta, Argentina. In these wide areas, actually known for the naturalistic value, a huge amount of archeological remains was found and surveyed for the first time in August 2013 within a research project funded by the Italian Ministry of Foreign Affairs. A methodological approach to record the findings in a cost-effective and reliable way is defined, acquisitions are performed with common use instruments such as digital cameras (off-the-shelf and single lens reflex - SLR) and measuring tapes. The novelty of the work lies in defining, experiencing and transferring to operators a simple methodology for digitizing and mapping the archeological heritage in order to provide 2D orthophotos and 3D models. Such methodology allows anyone, archaeologists or unprofessional personnel, to be trained and easily perform a survey in order to document, survey and study the investigated site.

2017 - An Integrated Procedure to Assess the Stability of Coastal Rocky Cliffs: From UAV Close-Range Photogrammetry to Geomechanical Finite Element Modeling [Articolo su rivista]
Mancini, Francesco; Castagnetti, Cristina; Rossi, Paolo; Dubbini, Marco; Fazio, Nunzio Luciano; Perrotti, Michele; Lollino, Piernicola
abstract

The present paper explores the combination of unmanned aerial vehicle (UAV) photogrammetry and three-dimensional geomechanical modeling in the investigation of instability processes of long sectors of coastal rocky cliffs. The need of a reliable and detailed reconstruction of the geometry of the cliff surfaces, beside the geomechanical characterization of the rock materials, could represent a very challenging requirement for sub-vertical coastal cliffs overlooking the sea. Very often, no information could be acquired by alternative surveying methodologies, due to the absence of vantage points, and the fieldwork could pose a risk for personnel. The case study is represented by a 600 m long sea cliff located at Sant’Andrea (Melendugno, Apulia, Italy). The cliff is characterized by a very complex geometrical setting, with a suggestive alternation of 10 to 20 m high vertical walls, with frequent caves, arches and rock-stacks. Initially, the rocky cliff surface was reconstructed at very fine spatial resolution from the combination of nadir and oblique images acquired by unmanned aerial vehicles. Successively, a limited area has been selected for further investigation. In particular, data refinement/decimation procedure has been assessed to find a convenient three-dimensional model to be used in the finite element geomechanical modeling without loss of information on the surface complexity. Finally, to test integrated procedure, the potential modes of failure of such sector of the investigated cliff were achieved. Results indicate that the most likely failure mechanism along the sea cliff examined is represented by the possible propagation of shear fractures or tensile failures along concave cliff portions or over-hanging due to previous collapses or erosion of the underlying rock volumes. The proposed approach to the investigation of coastal cliff stability has proven to be a possible and flexible tool in the rapid and highly-automated investigation of hazards to slope failure in coastal areas.

2017 - Critical issues and key points from the survey to the creation of the historical building information model: The case of Santo Stefano Basilica [Relazione in Atti di Convegno]
Castagnetti, Cristina; Dubbini, Marco; Ricci, Pier Carlo; Rivola, Riccardo; Giannini, Martina; Capra, Alessandro
abstract

The new era of designing in architecture and civil engineering applications lies in the Building Information Modeling (BIM) approach, based on a 3D geometric model including a 3D database. This is easier for new constructions whereas, when dealing with existing buildings, the creation of the BIM is based on the accurate knowledge of the as-built construction. Such a condition is allowed by a 3D survey, often carried out with laser scanning technology or modern photogrammetry, which are able to guarantee an adequate points cloud in terms of resolution and completeness by balancing both time consuming and costs with respect to the request of final accuracy. The BIM approach for existing buildings and even more for historical buildings is not yet a well known and deeply discussed process. There are still several choices to be addressed in the process from the survey to the model and critical issues to be discussed in the modeling step, particularly when dealing with unconventional elements such as deformed geometries or historical elements. The paper describes a comprehensive workflow that goes through the survey and the modeling, allowing to focus on critical issues and key points to obtain a reliable BIM of an existing monument. The case study employed to illustrate the workflow is the Basilica of St. Stefano in Bologna (Italy), a large monumental complex with great religious, historical and architectural assets.

2017 - Geodetic monitoring and geotechnical analyses of subsidence induced settlements of historic structures [Articolo su rivista]
Castagnetti, C; Cosentini, R M; Lancellotta, R; Capra, A
abstract

This paper focuses on the integration of geodetic monitoring and geotechnical modeling for the analyses of subsidence induced settlements in historic structures. The aim is the assessment of the behavior over time of the monuments, with particular attention to differential settlements, in order to evaluate the potential risk scenarios in a preventive strategy. The methodology is applied to the UNESCO site of Modena where the Cathedral and the Ghirlandina Tower are characterized by strong visible deformations due to a complex construction history, the peculiar subsoil conditions and the effects of both natural and man induced subsidence. A 3D finite element numerical model has been developed taking into account the soil characteristics gained by laboratory and in situ tests. The model takes into account the influence of previously existing structures, as well as the subsidence phenomena and provides a settlements profile in agreement with the real dataset collected by high-precision leveling. The geodetic monitoring, carried out since 1984, allows to optimize and then to validate the numerical model giving the Conservation Authority a useful tool to manage the safety of the heritage.

2017 - Image-based virtual tours and 3D modeling of past and current ages for the enhancement of archaeological parks: The VisualVersilia 3D project [Relazione in Atti di Convegno]
Castagnetti, Cristina; Giannini, Martina; Rivola, Riccardo
abstract

The research project VisualVersilia 3D aims at offering a new way to promote the territory and its heritage by matching the traditional reading of the document and the potential use of modern communication technologies for the cultural tourism. Recently, the research on the use of new technologies applied to cultural heritage have turned their attention mainly to technologies to reconstruct and narrate the complexity of the territory and its heritage, including 3D scanning, 3D printing and augmented reality. Some museums and archaeological sites already exploit the potential of digital tools to preserve and spread their heritage but interactive services involving tourists in an immersive and more modern experience are still rare. The innovation of the project consists in the development of a methodology for documenting current and past historical ages and integrating their 3D visualizations with rendering capable of returning an immersive virtual reality for a successful enhancement of the heritage. The project implements the methodology in the archaeological complex of Massaciuccoli, one of the best preserved roman site of the Versilia Area (Tuscany, Italy). The activities of the project briefly consist in developing: 1. the virtual tour of the site in its current configuration on the basis of spherical images then enhanced by texts, graphics and audio guides in order to enable both an immersive and remote tourist experience; 2. 3D reconstruction of the evidences and buildings in their current condition for documentation and conservation purposes on the basis of a complete metric survey carried out through laser scanning; 3. 3D virtual reconstructions through the main historical periods on the basis of historical investigation and the analysis of data acquired.

2017 - Relazione. Convegno Geores 2017. GEOMATICS & RESTORATION – Conservation of Cultural Heritage in the Digital Era, Firenze, 22-24 Maggio. Titolo dell’intervento: Critical Issues and key points from the survey to the creation of the historical building information model: the case of Santo Stefano Basilica. (C. Castagnetti, M. Dubbini, R. Rivola; P. C. Ricci, M. Agnoletti, M. Giannini, A Capra). [Altro]
Castagnetti, C.; Dubbini, M.; Rivola, R.; Ricci, P. C.; Agnoletti, M.; Giannini, M.; Capra, A.
abstract

The new era of designing in architecture and civil engineering applications lies in the Building Information Modeling (BIM) approach, based on a 3D geometric model including a 3D database. This is easier for new constructions whereas, when dealing with existing buildings, the creation of the BIM is based on the accurate knowledge of the as-built construction. Such a condition is allowed by a 3D survey, often carried out with laser scanning technology or modern photogrammetry, which are able to guarantee an adequate points cloud in terms of resolution and completeness by balancing both time consuming and costs with respect to the request of final accuracy. The BIM approach for existing buildings and even more for historical buildings is not yet a well known and deeply discussed process. There are still several choices to be addressed in the process from the survey to the model and critical issues to be discussed in the modeling step, particularly when dealing with unconventional elements such as deformed geometries or historical elements.

2017 - Relazione. Convegno Geores 2017. GEOMATICS & RESTORATION – Conservation of Cultural Heritage in the Digital Era, Firenze, 22-24 Maggio. Titolo dell’intervento: Imaged-based virtual tours and 3D modeling of past and current ages for the enhancement of archaeological parks: the VisualVersilia 3D project. (C. Castagnetti, M. Giannini, R. Rivola). [Altro]
Castagnetti, C.; Giannini, M.; Rivola, R.
abstract

The research project VisualVersilia 3D aims at offering a new way to promote the territory and its heritage by matching the traditional reading of the document and the potential use of modern communication technologies for the cultural tourism. Recently, the research on the use of new technologies applied to cultural heritage have turned their attention mainly to technologies to reconstruct and narrate the complexity of the territory and its heritage, including 3D scanning, 3D printing and augmented reality. Some museums and archaeological sites already exploit the potential of digital tools to preserve and spread their heritage but interactive services involving tourists in an immersive and more modern experience are still rare. The innovation of the project consists in the development of a methodology for documenting current and past historical ages and integrating their 3D visualizations with rendering capable of returning an immersive virtual reality for a successful enhancement of the heritage. The project implements the methodology in the archaeological complex of Massaciuccoli, one of the best preserved roman site of the Versilia Area (Tuscany, Italy). The activities of the project briefly consist in developing: 1. the virtual tour of the site in its current configuration on the basis of spherical images then enhanced by texts, graphics and audio guides in order to enable both an immersive and remote tourist experience; 2. 3D reconstruction of the evidences and buildings in their current condition for documentation and conservation purposes on the basis of a complete metric survey carried out through laser scanning; 3. 3D virtual reconstructions through the main historical periods on the basis of historical investigation and the analysis of data acquired.

2017 - Relazione. MetroArchaeo 2017. IMEKO International Conference on Metrology for Archaeology and Cultural Heritage, Lecce, Italy, October 23-25. Titolo dell’intervento: WebGIS, 3D modeling and virtual tours to map, record and visualize the cultural, archaeological and landscape heritage: the VisualVersilia project. (M. Giannini, C. Castagnetti, R. Rivola). [Altro]
Giannini, M.; Castagnetti, C.; Rivola, R.
abstract

This contribute describes the methodologies and technologies developed during the realization of the WebGIS (Geographic Information System) visualversilia.com, namely a multimedia guide able to map, survey, visualize the rich cultural, archaeological and landscape heritage of Versilia (northwestern Tuscany). It enables users to delve into different temporal settings and to contextualize the local cultural sites within the geographic space of their specific historical periods. The immersive experience is also achieved thanks to the realization of virtual tours and navigable 3D models of archaeological complexes concerning the past and current appearance. This WebGIS is a digital platform, soon available online, for viewing and managing data relative to the cultural sites of Versilia, through their localization on an interactive map with several thematic layers, divided into chronological sub-layers. The aim of the research project is to provide useful information for knowledge, protection and enhancement of the cultural heritage of the area.

2017 - VISUALVERSILIA 3D: VALORIZZARE I PARCHI ARCHEOLOGICI TRAMITE TOUR VIRTUALI E MODELLAZIONE 3D [Poster]
Castagnetti, Cristina; Giannini, Martina; Rivola, Riccardo
abstract

Il progetto di ricerca VisualVersilia 3D vuole offrire un nuovo modo di promuovere il territorio e il suo patrimonio, combinando alla lettura tradizionale del documento l’utilizzo delle moderne tecnologie di comunicazione per il turismo culturale. Negli ultimi anni, l'uso delle moderne tecnologie applicate al patrimonio culturale si è concentrato sulle metodologie di ricostruzione tridimensionale per raccontare in maniera empatica la complessità del territorio e del suo patrimonio; si pensi ad esempio alla rapida evoluzione che hanno avuto tecnologie quali la scansione 3D, la stampa 3D e la realtà virtuale ed aumentata. Alcuni musei e siti archeologici sfruttano già il potenziale degli strumenti digitali per valorizzare e diffondere il loro patrimonio, ma i servizi interattivi che coinvolgono i turisti in un'esperienza immersiva e più moderna sono ancora rari. L'innovazione del progetto è quella di sviluppare una metodologia per documentare la storia passata e presente integrandovi ricostruzioni 3D di epoche passate al fine di mostrare l’evoluzione temporale dei luoghi attraverso la realtà virtuale, realizzando così uno strumento coinvolgente ed emozionante in grado di incentivare la fruizione del patrimonio culturale e il turismo locale. Il progetto implementa la metodologia nel complesso archeologico di Massaciuccoli, uno dei luoghi romani meglio conservati della Versilia (Toscana, Italia). Le attività del progetto si basano, sinteticamente, sullo sviluppo di: 1. Un tour virtuale del sito nella sua attuale configurazione basato su immagini sferiche ad alta risoluzione, all’interno del quale sono inseriti testi, foto e guide audio/video per consentire l'esperienza turistica immersiva del sito da remoto; 2. Ricostruzione 3D dello stato attuale del complesso e del contesto territoriale per scopi di documentazione e di tutela basati su un'accurata conoscenza metrica dello stato di conservazione del sito ottenuta mediante scansione laser; 3. Ricostruzioni virtuali 3D del complesso durante i principali periodi storici basate sull'analisi storica tradizionale e sull'analisi dei dati metrici acquisiti.

2016 - Achievement of the “benchmark” session - on the use of UAV images for 3D reconstruction: a joint experience among users” (held during the 61th SIFET meeting, Lecce, Italy, june 8-10, 2016) [Articolo su rivista]
Mancini, Francesco; Castagnetti, Cristina; Rossi, Paolo; Altri, Autori
abstract

This paper summarize the achievements of an experimental meeting session held within the 61th SIFET national meeting (Lecce, Italy, 6-10 June 2016). The session named “benchmark” introduced results achieved by users in the processing of a shared dataset, composed of images acquired from unmanned aerial vehicle (UAV), to reconstruct the three-dimensional properties of cultural heritage. Data, results provided by authors and validation strategies of outcomes from the photogrammetric processing of UAV images highlighted different level of spatial accuracy by the products. Despite the good level of automation introduced by the structure from motion approach to data processing, the users detected differences at cm-level in the accuracy of results after the use of available software. ITA: Il lavoro riassume i risultati ottenuti da diversi partecipanti alla sessione “benchmark” - uso di immagini UAV per la ricostruzione 3D: esperienze condivise tra utenti, svoltasi nell’ambito del 61° convegno nazionale SIFET (Lecce 8-10 giugno 2016). L’iniziativa ha previsto l’elaborazione di un dataset comune, rappresentato da immagini acquisite tramite aeromobile a pilotaggio remoto, ai fini della ricostruzione tridimensionale di ambienti di pregio storico e culturale. Tra gli obiettivi principali vi era quello di confrontare i diversi approcci seguiti dai partecipanti nell’elaborazione dei dati, mettendo in luce le diverse potenzialità dei software disponibili, le possibili strategie relative all’uso dei punti di controllo e il livello di accuratezza raggiunto. Nonostante l’utilizzo di procedure consolidate nell’analisi dei dati, i risultati riportati dagli utenti evidenziano significative differenze nei livelli di accuratezza, verificabili dopo il confronto con i punti di controllo e con la nuvola di punti ottenuta con scansione laser terrestre.

2016 - Diagnostic Use of Laser Scanning Data to Identify Current and Historical Deformations and Geometries: the case of the Modena Cathedral [Relazione in Atti di Convegno]
Castagnetti, Cristina; Silvestri, Elena; Capra, Alessandro
abstract

The paper describes the semi-automatic methodology to analyze the verticality and the horizontality of structural and architectural elements of the Modena cathedral with the aim to use real dataset to validate the new hypothesis about the history of contruction. moreover, the integration with the crack pattern allows to compute the current deformations of the monument.

2016 - INTEGRAZIONE DI TECNICHE GEODETICHE PER LA CONOSCENZA E LA GESTIONE DI COMPLESSI MONUMENTALI: L’HISTORICAL BIM DI SANTO STEFANO A BOLOGNA [Abstract in Atti di Convegno]
Castagnetti, Cristina; Dubbini, Marco; Rivola, Riccardo; Ricci, Pier Carlo; Agnoletti, Michele; Giannini, Martina; Capra, Alessandro
abstract

L’attività di ricerca affronta il tema della documentazione e della conoscenza approfondita dello stato di fatto di complessi storici monumentali finalizzata alla loro tutela e conservazione. Il caso in esame è la Basilica di Santo Stefano a Bologna (BO), conosciuta anche come “Complesso Delle Sette Chiese”, la quale rappresenta un complesso storico di edifici di culto di grande pregio con età che vanno dal V al XI secolo. Agli occhi dei tecnici, il complesso rappresenta un insieme di strutture modificatisi nel tempo e integratesi l’una con l’altra fino a creare l’attuale bellezza e allo stesso tempo l’attuale complessità strutturale. Considerando la prospettiva di coloro che sono deputati alla tutela e conservazione dei beni culturali, Santo Stefano esemplifica, quindi, molto bene la necessità di conoscere in modo accurato e completo la geometria dello stato di fatto con tutte le variazioni architettonico/strutturali che ha subito il complesso nel tempo con il fine di monitorare l’evoluzione del monumento, progettare interventi di consolidamento e restauro nonché programmare e gestire correttamente la manutenzione. L’approccio che fin da subito è stato ritenuto necessario ed efficace per tutti questi scopi è la creazione di un modello geometrico BIM, Building Information Model.

2016 - Les portails et les sculptures de la cathédrale de Modène : problèmes d’histoire de l’art, de documentation, de conservation - II. Le relevé 3D [Relazione in Atti di Convegno]
Rivola, Riccardo; Bertacchini, Eleonora; Castagnetti, Cristina; Capra, Alessandro; Cadignani, Rossella; Piccinini, Francesca; Silvestri, Elena
abstract

The portals of the Cathedral of Modena, as well as the complex of architecture and sculpture of this important monument of Romanesque art in Italy, has long attracted the interest of several scholars in regard to various aspects: historical, structural, stylistic, iconographical. In the nineteenth century there were also partial surveys of the structure and the portals. During the twentieth century, in-depth studies on the architecture and sculpture have produced some campaigns of photogrammetry mapping and more recently laser-scanner measurements. In recent years the entire building and its bell tower (Torre “Ghirlandina”) were involved in a campaign of laserscanning conducted by the University of Modena and Reggio Emilia, which produced high-resolution surveys especially of the sculptures. These measurements were taken for documentation purposes, but also to control the state of conservation and monitoring of the sculptures and architectural structures.

2016 - Monitoring leaning towers by geodetic approaches: Effects of subsidence and earthquake to the Ghirlandina Tower [Articolo su rivista]
Castagnetti, Cristina; Bertacchini, Eleonora; Capra, Alessandro
abstract

The research focuses on structural monitoring and movements identification applied to cultural heritage safeguard. The final purpose is the integration among different and independent technologies for analyzing and investigating the geometry changing over time of ancient leaning towers. The paper deals with a novel strategy implemented by Authors to compute differential vertical displacements starting from results obtained by repeated high precision leveling network adjustments. These results usually aim at monitoring the subsidence phenomenon, while their use in engineering applications is more or less absent in literature. Moreover, the multidisciplinary approach is also able to analyze gradients of lowering in order to extrapolate the trend of the vertical axis and compute structure’s rotations. The approach is applied to the Ghirlandina Tower, Modena (Italy), in order to identify the leaning and the lowering trend. About thirty years of leveling campaigns provide a useful dataset to test the methodology, which is finally validated by the independent observations collected by a pendulum. The approach allows to compute the mean total displacement since 1984 of about 4.7 cm with 30% occurring over the last 6 years. In the same period, the total overhang of the Tower (1.30 m in 2007) increased of about 19.1 mm and 10.4 mm towards south-west. The approach is also able to identify anomalous behavior of the Tower such as the reversal tilting trend due to the scaffolding in the years of restoration and the permanent deformation suffered after the 2012 Emilia Romagna earthquake (failure of 4 mm in 6 months).

2016 - POTENTIALITY OF THE NEW WEARABLE SYSTEMS FOR 3D SCANNING AN EXPERIMENTATION OF PEGASUS BACKPACK BY LEICAGEOSYSTEMS PRESSO AT THE DUCAL PALACE OF MODENA [Articolo su rivista]
Castagnetti, Cristina; Mancini, Francesco; Rivola, Riccardo; Rossi, Paolo; Oppici, Simone; Albano, Valentina; Fiorentini, Marco
abstract

The terrestrial laser scanning is a well established technology for a wide range of applications. Recently the development of wearable systems based on multiple profilers and cameras opens to new challenging field of applications. The potentialities of such systems in terms of accuracy, productivity, completeness of the final dataset has been tested and described in the paper. The case study is provided by the Military Academy of Modena where an expeditious survey was carried out both in internal and external environments with the objective of evaluating the performance of the Leica Pegasus Backpack, a wearable system, in comparison with the Leica ScanStation C10, a traditional terrestrial laser scanner in static position. The field test allows to highlight the most suitable applications for these wearable systems.

2016 - Tecnologie 3D e loro integrazione per la conoscenza e la rappresentazione dei beni culturali: il BIM di Santo Stefano a Bologna. [Abstract in Atti di Convegno]
Castagnetti, Cristina; Rivola, Riccardo; Giannini, Martina; Capra, Alessandro
abstract

L’attività di ricerca affronta il tema della documentazione, della rappresentazione e della conoscenza approfondita dello stato di fatto di complessi storici monumentali finalizzata alla loro tutela e conservazione. Il caso in esame è la Basilica di Santo Stefano a Bologna (BO), insieme di strutture modificatisi nel tempo e integratesi l’una con l’altra fino a creare l’attuale bellezza e allo stesso tempo l’attuale complessità strutturale. La necessità di conoscere in modo accurato e completo la geometria dello stato di fatto con tutte le variazioni architettonico/strutturali subite nel tempo è cruciale per coloro che sono deputati alla tutela e conservazione del bene con il fine di monitorare l’evoluzione del monumento, progettare interventi di consolidamento e restauro nonché programmare e gestire correttamente la manutenzione. L’approccio ritenuto più efficace per tutti questi scopi è la creazione di un modello geometrico BIM, Building Information Model, del bene storico (H-BIM) in cui confluiscono le informazioni di natura geometrica e morfologica ottenute dai rilievi mentre i dati di natura qualitativa sono stati inseriti in un database online su piattaforma web interpellabile. L’aspetto unico e innovativo ricade principalmente nella metodologia che vede l’integrazione di molteplici tecnologie applicata alla straordinaria estensione e frammentarietà dell’intero complesso monumentale. Le attività, svolte nel 2012, hanno visto l’utilizzo di moderne tecniche di rilievo (laser scanning, livellazione di precisione, rilievo topografico e fotogrammetria da drone) e rappresentazione (modellazione BIM e restituzione grafica) nonché la creazione del primo esempio in Italia di H-BIM caratterizzato anche da tutte le anomalie geometriche tipiche di un edificio storico.

2016 - The geomatic techniques in support of the cultural properties. Digitalization and 3D print of a mosaic in Byzantine technique for documentation and conservation purposes [Articolo su rivista]
Rivola, Riccardo; Castagnetti, Cristina; Bertacchini, Eleonora; Casagrande, Francesca
abstract

Le moderne tecnologie di rilievo e restituzione 3D offrono enormi possibilità per la documentazione, la conservazione e la valorizzazione del patrimonio culturale. L’articolo illustra un’applicazione di rilievo laser scanning e prototipazione rapida su un mosaico a tecnica bizantina.

2015 - Award: MIT Innovators Under 35 Italy - Italian section of a global competition awarded by MIT Technology Review [Performance]
Castagnetti, Cristina
abstract

Innovators Under 35 è una competizione globale promossa da MIT Technology Review che seleziona i migliori profili di innovatori di età inferiore ai 35 anni con l'obiettivo di promuovere idee innovative e tecnologiche. I vincitori vengono scelti da una commissione competente italo statunitense.

2015 - Contribution of Geomatics Engineering and VGI Within the Landslide Risk Assessment Procedures [Relazione in Atti di Convegno]
Mancini, Francesco; Capra, Alessandro; Castagnetti, Cristina; Ceppi, C; Bertacchini, Eleonora; Rivola, Riccardo
abstract

This paper presents a literature review on the methodology called Volunteered Geographic Information (VGI) and its use for Landslide Risk Assessment (LRA). General risk assessment procedures are discussed and the potential contributions of VGI are identified, in particular when quantitative characterization of factors such as Hazard, Vulnerability and Exposure is required. The review shows that the standard LRA procedures may benefit from input given by surveyors when performing hazard assessments, while crowdsourced data would be a valuable support in vulnerability/damage assessment studies. The review also highlights several limitations related to the role of VGI and crowdsourcing in LRA.

2015 - Recent approaches in geodesy and geomatics for structures monitoring [Articolo su rivista]
Capra, Alessandro; Bertacchini, Eleonora; Castagnetti, Cristina; Rivola, Riccardo; Dubbini, Marco
abstract

Monitoring the time history of structures and infrastructures has always been an important area of application of geodetic and geomatic methods. Here we shall concentrate on the item of monitoring ancient buildings because, beyond its intrinsic interest, it provides a good illustration of some of the most recent monitoring techniques. Identifying the overhang, progressive changes of inclination, differential movements of the structure and detailing the study of structural elements are just some examples of the many fundamental and necessary information for structural engineers. Those data are required to study and analyze the behavior of a structure with the purpose to assess the stability . Looking at the several methods offered by Geomatics, laser scanning appears to be the best technology to provide an effective 3D solution to those requirements. Surveying by means of a terrestrial laser scanner, allows to detect a huge number of 3D information with high accuracy in a relatively short time and high accuracy. Just analyzing the point clouds, interesting information along with useful products can be obtained in order to draw some considerations about the investigated structure. This research aims at suggesting a new philosophy for using 3D models in a diagnostic perspective in order to study structures along with their actual dimensions, their stability and so on. Traditionally, indeed, laser scanning is chosen for artistic and architectural studies and the resulting three-dimensional model represents what often is of concern. Furthermore, the use of more classic techniques, such as total station and digital leveling, and LST is fundamental as an integrated approach for the monitoring of ancient buildings. The integration of different techniques allow a redundancy of observation and the possibility to verify the results obtained form independent techniques as is shown throughout some experimental applications.

2015 - Rilievi metrici 3D laser scanning: la torre e le sculture [Capitolo/Saggio]
Bertacchini, Eleonora; Capra, Alessandro; Castagnetti, Cristina; Rivola, Riccardo; Toschi, Isabella
abstract

L’utilizzo delle tecniche di rilievo messe a disposizione dalle discipline geomatiche si dimostra sempre più un prezioso supporto per gli interventi di valorizzazione, restauro e conservazione dell’immenso patrimonio culturale da cui è caratterizzato il nostro Paese. Il contributo descrive le attività di rilievo laser scanning ad altissima risoluzione svolte sull'apparato scultore della Torre Ghirlandina, sito UNESCO di Modena, e le attività di modellazione 3D per la costruzione di un database idoneo alla riproduzione materia delle sculture per scopi conservativi e di valorizzazione.

2015 - 3D reconstruction of an underwater archaelogical site: comparison between low cost cameras [Relazione in Atti di Convegno]
Capra, Alessandro; Dubbini, M; Bertacchini, Eleonora; Castagnetti, Cristina; Mancini, Francesco
abstract

The 3D reconstruction with a metric content of a submerged area, where objects and structures of archaeological interest are found, could play an important role in the research and study activities and even in the digitization of the cultural heritage. The reconstruction of 3D object, of interest for archaeologists, constitutes a starting point in the classification and description of object in digital format and for successive fruition by user after delivering through several media. The starting point is a metric evaluation of the site obtained with photogrammetric surveying and appropriate 3D restitution. The authors have been applying the underwater photogrammetric technique since several years using underwater digital cameras and, in this paper, digital low cost cameras (off-the-shelf). Results of tests made on submerged objects with three cameras are presented: (c) Canon Power Shot G12, (c) Intova Sport HD e (c) GoPro HERO 2. The experimentation had the goal to evaluate the precision in self-calibration procedures, essential for multimedia underwater photogrammetry, and to analyze the quality of 3D restitution. Precisions obtained in the calibration and orientation procedures was assessed by using three cameras, and an homogeneous set control points. Data were processed with (c) Agisoft Photoscan. Successively, 3D models were created and the comparison of the models derived from the use of different cameras was performed. Different potentialities of the used cameras are reported in the discussion section. The 3D restitution of objects and structures was integrated with sea bottom floor morphology in order to achieve a comprehensive description of the site. A possible methodology of survey and representation of submerged objects is therefore illustrated, considering an automatic and a semi-automatic approach.

2014 - A reliable methodology for monitoring unstable slopes: the multi-platform and multi-sensor approach [Relazione in Atti di Convegno]
Castagnetti, Cristina; Bertacchini, Eleonora; Corsini, Alessandro; Rivola, Riccardo
abstract

High resolution topography, by involving Digital Terrain Models (DTMs) and further accurate techniques for a proper displacement identification, is a valuable tool for a good and reliable description of unstable slopes. By comparing multitemporal surveys, the geomorphology of a landslide may be analyzed as well as the changes over time, the volumes transportation and the boundaries evolution. Being aware that a single technique is not sufficient to perform a reliable and accurate survey, this paper discusses the use of multi-platform, multi-source and multi-scale observations (both in terms of spatial scale and time scale) for the study and monitoring of unstable slopes. The final purpose is to highlight and validate a methodology based on multiple sensors and data integration, useful to obtain a comprehensive GIS (Geographic Information System) which can successfully be used to manage natural disasters or to improve the knowledge of a specific phenomenon in order to prevent and mitigate the hydro-geological risk. The novelty of the present research lies in the spatial integration of multiple remote sensing techniques such as: integration of Airborne Laser Scanning (ALS) and Terrestrial Laser Scanning (TLS) to provide a comprehensive and accurate surface description (DTM) at a fixed epoch (spatial continuity); continuous monitoring by means of spatial integration of Automated Total Station (ATS) and GNSS (Global Navigation Satellite System) to provide accurate surface displacement identification (time continuity). Discussion makes reference to a rockslide located in the northern Apennines of Italy from 2010 to 2013. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

2014 - GEIS - Geomatics Engineering Innovative Solutions Srl [Spin Off]
Castagnetti, Cristina; Rivola, Riccardo; Bertacchini, Eleonora; Capra, Alessandro; Università di, Modena e. Reggio Emilia
abstract

GEIS è una startup operativa nel campo del rilievo e restituzione tridimensionale con tecnologie integrate. I principali ambiti di attività sono la meccanica di precisione, il facility management, le costruzioni e l'edilizia. Occupandosi di digitalizzaizone 3D di processi e di prodotti, GEIS con i suoi servizi concretizza l'industria 4.0 e accompagna le imprese nel processo di innovazione anche con la formazione.

2014 - Integrating low-frequency and high-frequency geodetic techniques for structural monitoring [Abstract in Atti di Convegno]
Castagnetti, Cristina; Capra, Alessandro; Bertacchini, Eleonora
abstract

2014 - Remotely Piloted Aircraft Systems (RPAS) for high resolution topography and monitoring: civil protection purposes on hydrogeological contexts [Relazione in Atti di Convegno]
Bertacchini, Eleonora; Castagnetti, Cristina; Corsini, Alessandro; De Cono, Stefano
abstract

The proposed work concerns the analysis of Remotely Piloted Aircraft Systems (RPAS), also known as drones, UAV (Unmanned Aerial Vehicle) or UAS (Unmanned Aerial System), on hydrogeological contexts for civil protection purposes, underlying the advantages of using a flexible and relatively low cost system. The capabilities of photogrammetric RPAS multi-sensors platform were examined in term of mapping, creation of orthophotos, 3D models generation, data integration into a 3D GIS (Geographic Information System) and validation through independent techniques such as GNSS (Global Navigation Satellite System). The RPAS used (multirotor OktoXL, of the Mikrokopter) was equipped with a GPS (Global Positioning System) receiver, digital cameras for photos and videos, an inertial navigation system, a radio device for communication and telemetry, etc. This innovative way of viewing and understanding the environment showed huge potentialities for the study of the territory, and due to its characteristics could be well integrated with aircraft surveys. However, such characteristics seem to give priority to local applications for rigorous and accurate analysis, while it remains a means of expeditious investigation for more extended areas. According to civil protection purposes, the experimentation was carried out by simulating operational protocols, for example for inspection, surveillance, monitoring, land mapping, georeferencing methods (with or without Ground Control Points - GCP) based on high resolution topography (2D and 3D information).

2013 - Integrating airborne and multi-temporal long-range terrestrial laser scanning with total station measurements for mapping and monitoring a compound slow moving rock slide [Articolo su rivista]
Corsini, Alessandro; Castagnetti, Cristina; Bertacchini, Eleonora; Rivola, Riccardo; Ronchetti, Francesco; Capra, Alessandro
abstract

A slow moving compound rock slide located in the northern Apennines of Italy was mapped and monitored through the integration of Airborne Laser Scanning (ALS), multi-temporal long-range Terrestrial Laser Scanning (TLS), and Automated Total Station (ATS) measurements. Landslide features were mapped using a High Resolution Digital Terrain Model (HR-DTM) obtained by merging ALS and TLS data in an Iterative Closest Point (ICP) procedure. Slope movements in the order of centimeters to a few decimeters were quantified with Differential TLS (D-TLS) based on a Surface Matching approach and supported by ATS data to define stable reference surfaces. The integrated approach allowed mapping of the composite geomorphic features of the rock slide under examination, revealing its complex dynamic nature and further proving that laser scanning is a versatile and widely applicable tool for slope process analysis

2013 - Large-scale slope instability affecting SS63 near the Cerreto Pass (northern Apennines, Italy) [Relazione in Atti di Convegno]
Corsini, Alessandro; Ronchetti, Francesco; Bertacchini, Eleonora; Bonacini, Francesco; Calicetti, P; Capra, Alessandro; Castagnetti, Cristina; Piantelli, E; Caputo, G; Truffelli, G.
abstract

National Road SS63 is endangered by large scale slope instability phenomena few km north of the Cerreto Pass (northern Apennines, Italy). At the Col Piagneto slope, SS63 was closed two times in the past 50 years after landslide events. In 1974, the collapse of portion of a rock slide triggered a debris slide that buried more than 50 m of the road track. In 2008, the reactivation of an earth slide in eastern portion of the slope damaged about 400 m of the “new” track built to by-pass the 1974 risk area. In order to evaluate if it is worthwhile keeping the old track open to traffic, or it is maybe better to repair the new track a comprehensive study was financed by Emilia Romagna Region. Research methods included: high resolution DEM, landslides mapping, continuous displacement and groundwater monitoring. Results allowed to assess different semi-quantitative risk scenario for the road structures or vehicles.

2013 - Multi-sensors integrated system for landslide monitoring: critical issues in system setup and data management [Articolo su rivista]
Castagnetti, Cristina; Bertacchini, Eleonora; Corsini, Alessandro; Capra, Alessandro
abstract

This paper discusses critical issues related to the reliability of topographic monitoring systems such as ATS (Automated Total Stations), GNSS (Global Navigation Satellite System) and Ground Based InSAR focusing the attention on controlling the stability of networks infrastructure, which have influence on data correction procedures but are often taken for granted, and on integrating results in GIS (Geographic Information System), under a common reference framework and with respect to open-access ancillary data. The novelty of the paper lies in the demonstration of the efficiency obtained by a proper implementation of the system. Discussion makes reference to an active landslide by using ATS, GNSS and Ground Based InSAR in continuous and periodic mode

2013 - Recording systems. GPS satellites for archaeology: surveying around the Puruhuay Lake [Capitolo/Saggio]
Castagnetti, Cristina; Capra, Alessandro
abstract

This chapter deals with the various surveying methods that have been applied to the Puruhuay area. For the study of ancient settlement systems, it is essential to integrate archeological, topographic and geodetic applications, which provide essential geographic information for the archeological interpretation of settlement systems. The contribution of surveyors, engineers and geologists within the team of archaeologists increased the amount of data collected during each field campaign. The chapter describes with details the survey carried out by using GPS technology and the maps production obtained by GIS approach.

2013 - Validation tests of open-source procedures for digital camera calibration and 3D image-based modelling [Relazione in Atti di Convegno]
Toschi, Isabella; Rivola, Riccardo; Bertacchini, Eleonora; Castagnetti, Cristina; Dubbini, Marco; Capra, Alessandro
abstract

Among the many open-source software solutions recently developed for the extraction of point clouds from a set of un-oriented images, the photogrammetric tools Apero and MicMac (IGN, Institut Géographique National) aim to distinguish themselves by focusing on the accuracy and the metric content of the final result. This paper firstly aims at assessing the accuracy of the simplified and automated calibration procedure offered by the IGN tools. Results obtained with this procedure were compared with those achieved with a test-range calibration approach using a pre-surveyed laboratory test-field. Both direct and a-posteriori validation tests turned out successfully showing the stability and the metric accuracy of the process, even when low textured or reflective surfaces are present in the 3D scene. Afterwards, the possibility of achieving accurate 3D models from the subsequently extracted dense point clouds is also evaluated. Three different types of sculptural elements were chosen as test-objects and "ground-truth" data were acquired with triangulation laser scanners. 3D models derived from point clouds oriented with a simplified relative procedure show a suitable metric accuracy: all comparisons delivered a standard deviation of millimeter-level. The use of Ground Control Points in the orientation phase did not improve significantly the accuracy of the final 3D model, when a small figure-like corbel was used as test-object.

2012 - Critical aspects of an integrated monitoring system for landslides risk management: strategies for a reliable approach [Abstract in Atti di Convegno]
Castagnetti, C.; Bertacchini, E.; Capra, A.; Corsini, A.
abstract

2012 - Estrazione di DTM da una stereocoppia Worldview-1: procedure di orientamento, image-matching e rimozione degli edifici [Articolo su rivista]
Bertacchini, Eleonora; Toschi, Isabella; Rivola, Riccardo; Castagnetti, Cristina; Capra, Alessandro
abstract

L’utilizzo di immagini satellitari ad alta risoluzione acquisite in modalità stereoscopica si sta affermando quale strumento proficuo per la generazione di Modelli Digitali del Terreno (DTM) e della Superficie (DSM). La sfida che si apre oggi è quella di poter rispondere adeguatamente alle esigenze di base di molti settori applicativi, che necessitano di accurati strumenti per la conoscenza della morfologia del territorio e dei suoi mutamenti. Il presente lavoro si è proposto di analizzare e validare le principali fasi in cui si articola la procedura di estrazione di modelli digitali tridimensionali a partire da immagini satellitari, utilizzando quale caso applicativo una stereocoppia pancromatica acquisita along-track dal satellite WorldView-1 nella zona dei colli Albani, a Sud-Est di Roma. L’obiettivo principale è stato quello di individuare un approccio che potesse unire all’accuratezza del dato metrico finale anche il vantaggio di rendere quest’ultimo un adeguato strumento di descrizione della morfologia di ampie porzioni di territorio: in particolare, è stata associata all’estrazione del DSM, quella di un DTM tramite la classificazione ed eliminazione degli oggetti in elevazione sul terreno (ERDAS Imagine 2011). La parte iniziale della sperimentazione è stata volta a confrontare l’accuratezza perseguibile utilizzando il modello parametrico rigoroso e i metodi razionali per la correzione geometrica delle immagini: a tale scopo, sono stati analizzati e confrontati i risultati ottenuti nella fase di orientamento e in quella successiva di estrazione del modello digitale. Il cuore della ricerca sono stati l’applicazione e il confronto di due procedure alternative volte ad ottenere come risultato finale il modello tridimensionale del terreno depurato dalla presenza degli edifici. A tale scopo è stato sperimentato l’algoritmo di classificazione automatica di LPS-eATE, agente contestualmente alla fase di estrazione dell’informazione altimetrica; i risultati ottenuti sono stati confrontati con quelli conseguiti tramite un approccio alternativo, basato sull'estrazione del modello digitale a partire dalle immagini classificate con metodo object-oriented tramite il software eCognition Developer vs. 8.64.1. Entrambe le procedure testate hanno evidenziato potenzialità interessanti e ulteriormente migliorabili, soprattutto in relazione alla fase di interpolazione della nuvola di punti estratta a partire dalle immagini classificate con il secondo approccio.

2012 - Investigating an active rockslide by long-range laser scanner: alignment strategy and displacements identification [Relazione in Atti di Convegno]
Bertacchini, Eleonora; Capra, Alessandro; Castagnetti, Cristina; Rivola, Riccardo
abstract

Landslides are considered one of the major natural hazards in mountain regions. Nowadays landslides monitoring has become a central issue for Authorities to be able to anticipate hazards. For this reason, several examples exist about landslides monitoring; they may be installed in different configurations depending on purposes and economic resources.The heart of this research is to detect an efficient methodology for the reliable acquisition and interpretation of Terrestrial Laser Scanning (TLS) data: the final purpose is a proposal for a methodology which is based on TLS technology for identifying displacements and extracting geomorphological changes. The approach is clearly based on a multi-temporal analysis which is computed on several repetitions of TLS surveys performed on the area of interest. To achieve best results and optimize the processing strategy, different methods about point clouds alignment have been tested, together with algorithms both for filtering and post- processing. The final aim is also to provide a sort of guidelines about a suitable way for planning and properly carrying out TLS surveys.The case study is the Col Piagneto landslide, located in the North Apennines (Reggio Emilia, Italy) on the right flank of Biola torrent. The large scale composite landslide area is made both by a wide rock slide sector and a more limited earth slide sector. An integrated monitoring system is installed since 2009 and comprises both point-based technologies (extensometers, total station and global positioning system), as well as area-based ones (airborne laser scanner, long-range TLS and ground-based radar). This choice combines the advantages of both approaches.The research focuses on TLS surveys for trying to detect displacements which might be considered responsible for instability. By sequentially analyzing TLS surfaces, displacement maps have been obtained for the rockslide area. Confirmation can be achieved by comparing results with movements of reflectors located on the slope and continuously measured by total station. Such validation strengthens the idea that TLS may be successfully used for analyzing instability.

2012 - Mappatura GPS delle ippovie e individuazione siti di interesse culturale. Un WebGIS per il turismo equestre [Articolo su rivista]
Castagnetti, Cristina; Capra, Alessandro; Bedostri, Irene; Bedostri, Tiziano
abstract

L'articolo descrive una sperimentazione svolta nell'ambito del progetto "Turismo equestre" in collaborazione con il comitato emilia romagna della Federazione Italiana Sport Equestri volta a mappare attraverso l'utilizzo di strumentazione GPS le ippovie e creare con strumenti GIS dei percorsi da condividere con utenti del settore. L'articolo illustra le potenzialità e i limiti di utilizzo di strumentazione geodetica a questo scopo.

2012 - Tecniche Laser Scanner per la rappresentazione dei beni culturali: il rilievo dell’apparato scultoreo della Torre Ghirlandina di Modena [Relazione in Atti di Convegno]
Bertacchini, Eleonora; Capra, Alessandro; Castagnetti, Cristina; Rivola, Riccardo; Toschi, Isabella
abstract

2012 - Terrestrial Laser Scanning for Preserving Cultural Heritage: Analysis of Geometric Anomalies for Ancient Structures [Relazione in Atti di Convegno]
Castagnetti, Cristina; Bertacchini, Eleonora; Capra, Alessandro; Dubbini, Marco
abstract

Identifying the overhang, progressive changes of inclination, differential movements of the structure and detailing the study of structural elements are just some examples of the many fundamental information for structural engineers. Those data are required to study and analyze the behavior of a structure with the purpose to assess the stability . Laser scanning appears to be the best technology to provide an effective solution to those requirements. Surveying by means of a terrestrial laser scanner (TLS), allows to detect a huge number of information with relatively short time and high accuracy. Those data, then, do not necessarily need to be used to reconstruct the three dimensional surface model. Just analyzing the point clouds, interesting information along with useful products can be obtained in order to draw some considerations about the investigated structure. This research aims to suggest a new philosophy for using TLS in a diagnostic perspective in order to study structures along with their actual dimensions, their stability and so on. This new approach, characterized by a well- advanced vision, is really different from the traditional one because of the engineering point of view with respect to the usual application of TLS. Traditionally, indeed, laser scanning is chosen for artistic and architectural studies and the resulting three-dimensional model represents what often is of concern.The research focuses on the Cathedral of Modena, one of the most important pieces of Romanesque culture in Europe (UNESCO World Heritage List since 1997). The overall motivation of this research is to preserve the cultural heritage we are responsible for, as long as spectators. Thus, the final purpose is to illustrate the methodology to compute anomalies in structural geometry by means of TLS in order to provide an accurate description of the structure that is particularly useful for structural engineers, architects and art historians. Both outdoor as well as indoor TLS surveys were performed. The geometry of the structure was properly described by analyzing point clouds; specific measurements were focused on constituent elements with the aim of detecting anomalies of the geometric configuration. Geometric anomalies might be read as the result of deformations occurred in the past or as future deformations due to an abnormal geometric configuration. Investigations about the identified anomalies will be presented together with differential movements obtained by high precision leveling focused on a network of benchmarks that were installed along the outside perimeter. The integration of independent techniques allows to check for consistency of results.

2011 - Atmospheric corrections for topographic monitoring systems in landslides. [Relazione in Atti di Convegno]
Bertacchini, Eleonora; Capra, Alessandro; Castagnetti, Cristina; Corsini, Alessandro
abstract

SUMMARYNew automated “long range” total stations are actually available for monitoring landslides, dams, structures etc. The use of total station is consolidate within some hundred meters of distance and with a supervisor. But the long range (up to 3 km) measurements are not still completely investigated in operating condition. When the accuracy and the precision required are important, seems to be necessary to investigate the atmosphere influence on distance measurements. The research deals with the study of a landslide topographic monitoring system: the Collagna Landslide (Reggio Emilia, Italy) monitoring system. It consists of an automated long range total station acquiring about 36 prisms ,every 4 hours, since 2009. The idea was to test how atmospheric corrections could improve the measurements precision and accuracy to exploit the system capabilities. Some tests on the total station EDM (Electronic Distance Measuring) system are presented in operating conditions. Particularly attention was paid to the long distances dependence on atmospheric conditions (temperature, pressure and relative humidity). Two kinds of corrections were applied, that of the instrument and one of the literature. Some differences were found on atmospheric corrections calculated with the two different methods. But it seems that atmospheric corrections can really improve the final result accuracy.

2011 - Con una pacarina a la vista: arquitectura como construccion de autoridad alrededor de la laguna de Puruhuay [Capitolo/Saggio]
Orsini, Carolina; Benozzi, Elisa; Debandi, Florencia; Capra, Alessandro; Boni, Emanuele; Castagnetti, Cristina
abstract

Commencing in the eleventh century A.D. a series of settlements and ceremonial sites, in close relationship with the Puruhuay Lake and the waterfall “María Jiray” (Acopalca district, Huari, Ancash) were constructed. The majority of these sites have been studied during the archaeological campaigns of the Project «Antonio Raimondi» between 2006 and 2009. The close relationship between the sites is evident not only because they were built during the same period and within a contiguous territory, but also because of the uniform type of architecture. The complex of settlements built around the lake appear as a planned system of control of a natural place; a natural site that is considered an important pacarina even today, and a resource of great importance for the local economy.

2011 - Design of a Low-cost GPS/magnetometer System for Land-based Navigation: Integration and Autocalibration Algorithms [Relazione in Atti di Convegno]
Castagnetti, Cristina; Biagi, Ludovico; Capra, Alessandro
abstract

The land-based navigation, paying attention to precision farming, is the research topic: the final purpose is the design and development of a guidance-aided system focusing on a low-cost GPS receiver able to provide a pseudorange-based solution only. Specific tests have been carried out to reproduce the trajectories followed by the vehicle in agricultural applications, whose accuracy target is typically 1 m. Results show that the investigated low-cost receiver is affected by a drift in time which is mainly detected while turning and causing a deviation from the optimal reference solution. Thus, the goal is to correct this behavior because the deviation accumulates during time and causes a not optimal treatment of the field (waste of material and money). Paying attention to the cost of the system, a new idea is proposed: the integration between the low-cost GPS with a magnetometer/digital compass. A dedicated algorithm has been also implemented, taking the heading provided by th e magnetometer and using it to correct the deviation in turns. Unluckily a magnetometer is deeply influenced by ferrous materials and the sensor is supposed to be installed on the vehicle, which is mainly made by metal. As a consequence, the sensed measurements are affected by a deviation from the actual magnetic field. Those disturbances need to be properly reduced by an autocalibration procedure. A new approach for the autocalibration problem has been developed and implemented; then the comparison with respect to the traditional method has been also performed in order to test and validate the new idea. A comprehensive and detailed description of all the algorithms will be produced concerning both the sensors integration (GPS and magnetometer) along with the magnetometer autocalibration. Particular attention will be focused on results and performances of the autocalibration procedure, which appears to provide very interesting results. The new approach, which is simply based on the covariance matrix, appears to be more successful than the traditional one. Several tests have been analyzed: the stand-alone low-cost GPS provides solutions which are not acceptable for precision farming applications, while the integration with a magnetometer slightly increases the accuracy. Furthermore, the innovation of the research is connected to the autocalibration algorithm itself. The final goal was the design of a low-cost system for supporting the guidance in land-based navigation; improvements are still required but the goal is close to be achieved.

2011 - GPS potentiality (strategies) for supporting archaeology: preventive investigation and memory of an excavation [Abstract in Atti di Convegno]
Castagnetti, C.; Bertacchini, E.; Capra, A.; Orsini, C.; Dubbini, M.
abstract

2011 - GPS-aided land-based navigation and precision farming applications: improving GPS accuracy by means of MEMS IMU and low-cost sensors [Capitolo/Saggio]
Castagnetti, Cristina
abstract

The main topic of this research was the use of low-cost GPS (Global Positioning System) for land-based navigation with particular attention to precision farming applications. In order to improve GPS solutions, the integration with additional sensors, such as magnetometers and IMU (Inertial Measurement Unit), was investigated. Those GPS, indeed, do not store any raw data but just provide a NMEA format data stream containing coordinates. They were obtained by a single point positioning based on code signal only. A solution to this problem still exists: it is obvious how such system could be improved by using a differential (DGPS or RTK) approach. Allowing to receive corrections, it would provide a decimeters or centimeters level of accuracy, respectively. The point is that it would not be anymore a low-cost system: the problem of achieving a sub-meter accuracy can be solve despite of a higher cost. The challenge is to find a cheaper solution and improve pseudorange-based GPS operating in a stand-alone mode. Concerning the application field, that is land-based navigation, some essential aspects still appear to be critical: just an example, a lot of unsolved inconveniences occur because of frequent GPS losses of lock in urban canyons.

2011 - IL LASER SCANNING TERRESTRE PER L'ANALISI DI EDIFICI DI INTERESSE STORICO ED ARTISTICO [Capitolo/Saggio]
Castagnetti, Cristina; Bertacchini, Eleonora; Capra, Alessandro; Dubbini, Marco
abstract

Identifying the overhang, progressive changes of inclination, differential movements of the structure and detailing the study of structural elements are just some examples of the many fundamental and necessary information for structural engineers. Those data are required to study and analyze the behaviour of a structure with the purpose to assess the stability . Looking at the several methods offered by Geomatics, laser scanning appears to be the best technology to provide an effective solution to those requirements. Surveying by means of a terrestrial laser scanner, allows to detect a huge number of information with relatively short time and high accuracy. Those data, then, do not necessarily need to be used to reconstruct the three dimensional surface model. Just analyzing the point clouds, interesting information along with useful products can be obtained in order to draw some considerations about the investigated structure.This research aims to suggest a new philosophy for using the laser scanner in a diagnostic perspective in order to study structures along with their actual dimensions, their stability and so on. This new approach, characterized by a well-advanced vision, is very different from the traditional one because of the engineering point of view with respect to the usual application of laser scanner. Traditionally, indeed, laser scanning is chosen for artistic and architectural studies and the resulting three-dimensional model represents what often is of concern. Some case studies will be presented; they are characterized by different kinds of structures suffering from various problems: the Cathedral of Modena and the Ghirlandina Tower UNESCO-World Heritage (Italy), "della Sagra" Tower in Carpi (Modena – Italy) and Asinelli Tower in Bologna (Italy). The final purpose is to illustrate the methodology to perform the structural analysis by means of terrestrial laser scanning. Furthermore, examples will be presented about extraction of interesting products and results.

2011 - Integrating LIDAR and terrestrial laser scanning for a full and reliable description of landslides geomorphology [Abstract in Atti di Convegno]
Castagnetti, C.; Bertacchini, E.; Capra, A.; Dubbini, M.; Rivola, R.; Corsini, A.
abstract

2011 - Registrazione di scansioni laser scanner: potenzialità del metodo diretto. [Articolo su rivista]
Rivola, Riccardo; Bertacchini, Eleonora; Castagnetti, Cristina; Toschi, Isabella; Capra, Alessandro
abstract

Laser scanning technology has emerged on the surveying instrument scene relatively recently, revolutionizing traditional surveying methodologies. In some cases, users rely blindly on this new instrumentation, without bothering to verify its reliability and assess its true potential. For this reason, it was decided to undertake a study to identify the more efficient laser scanning survey techniques and methodologies. The tests were carried out using a pulsed laser scanner and initially focused on traverse precision and accuracy, comparing measurements of that instrument with those of a robotic total station. Subsequent tests analyzed in detail the quality of the direct registration scanning technique compared to the traditional indirect method and the Iterative Closest Point (ICP) procedure. Scan alignment by the direct method takes traverses directly from the Terrestrial Laser Scanner (TLS), thus decoupling acquisition from the traditional topographic instruments used for the support measurements. Comprehensive analysis of these results confirms, for architectural surveys, the more efficient and productive survey methodology has been identified as a function of the object type, the desired result and the time available.

2011 - Rilievi integrati per il monitoraggio e la gestione dell’instabilità dei versanti [Capitolo/Saggio]
Bertacchini, Eleonora; Castagnetti, Cristina; Capra, Alessandro; Rivola, Riccardo; Corsini, Alessandro
abstract

Nowadays civil protection and environment safeguard are of topical interest. The hydro-geological instability and landslides as well, in fact, are serious problems that unfortunately characterize our whole country. The consequences are sometimes severe and there is more to deal with such as emergencies and disasters directly affecting the population. Geomatics, in this sense, offers a wide variety of methodologies and technologies, both well-established and well-advanced, functioning as an important support to the control and monitoring of territory. Key studies concern the phenomenon itself, risk prevention and emergency management . Concerning that, the present paper presents the design and implementation of an integrated system based on topographical and geotechnical instrumentation with the purpose to continuously monitor a landslide. Two case studies will be presented: they are both located in the Apennines of Emilia-Romagna Region. The system consists of a robotic total station located in a geologically stable area together with a GNSS (Global Navigation Satellite System) receiver which acts as a permanent master station. The robotic total station regularly runs several times a day repeating the same action, which consists on measuring a series of prisms positioned both inside and outside of the landslide body. A two-directions inclinometer monitors the stability of the monument in real-time mode. An additional GNSS, acting as a rover receiver, has been placed at the edge of the landslide to assess over time the possible extension of the phenomenon (continuous monitoring). The monitoring system, operating in continuous mode, is remotely managed; this allows a constant control on displacements and ensures a rapid and effective action in case of emergency . Together with the topographic instruments, some extensometers, inclinometers and piezometers were installed with the aim to study the deformation mechanism of the investigated phenomenon. LIDAR (Light Detection And Ranging) surveys were carried out to obtain the DTM (Digital Terrain Model) and high accuracy orthophotos of the area. Periodical flights were performed to detect and study the subsequent reactivations. The present research aims to present some phenomena, which are similar to many others in the country, with the aim of strengthening the role, the importance and the usefulness of Geomatics in the monitoring of the territory.

2011 - Rilievi laser scanner per l’analisi geometrica delle torri degli Asinelli e Garisenda. [Articolo su rivista]
Capra, Alessandro; Bertacchini, Eleonora; Castagnetti, Cristina; Dubbini, Marco; Rivola, Riccardo; Toschi, Isabella
abstract

The Tower of Asinelli and the Garisenda Tower, represent structures with high level of historical content and symbolize the city of Bologna. Erected in the XII century by noble “ghibelline” families, both towers present an evident overhang that led to the choise of a surveying methodology to analyze the geometry of the structures. In this paper the studies conducted on the 3D models of the Towers obtained with laser scanning technology are presented. In both cases, the choices taken during the experimentations, from the execution of the survey to the extraction of information of interest, were conducted to make repeatable analysis and lay the foundation for monitoring the structural behavior.

2011 - Utilizzo del laser scanner per i beni culturali: analisi dell’assetto geometrico strutturale e di specifiche anomalie geometriche [Relazione in Atti di Convegno]
Bertacchini, Eleonora; Capra, Alessandro; Castagnetti, Cristina; Dubbini, Marco; Rivola, Riccardo; Toschi, Isabella
abstract

RIASSUNTO:La tecnologia Laser Scanner Terrestre (LST) permette di ottenere il modello tridimensionale complessivo di qualsiasi oggetto con elevata accuratezza e, per questo motivo, risulta oggi sempre più applicata in ambito architettonico. E’ tuttavia necessario identificare l’approccio più adeguato in relazione alla tipologia di oggetto e allo scopo finale del rilievo, intendendo con questo sia la scelta della strumentazione da utilizzare sia l’adozione di specifiche tecniche per il trattamento dei dati.Il presente lavoro si propone di sperimentare l’applicazione della tecnologia LST a strutture di elevato pregio architettonico – culturale: la Torre degli Asinelli e la Torre Garisenda (Bologna). Entrambe richiedono un’attenta analisi strutturale in quanto il loro prevalente sviluppo verticale, denotato da altezza e snellezza significative, le rende una tipologia costruttiva particolarmente delicata. In entrambi i casi il rilievo, eseguito con un laser scanner distanziometrico ad impulsi, ha permesso di ottenere il modello complessivo della struttura con risoluzione sub-centimetrica. Nello specifico, lo studio applicato alla Torre degli Asinelli è stato volto alla determinazione di informazioni generali sull’assetto geometrico della struttura: sono stati infatti ricavati l’altezza della Torre, lo sviluppo del suo asse longitudinale e lo strapiombo. Le analisi relative alla Garisenda hanno invece interessato la fascia selenitica della Torre: all’analisi geometrica delle sezioni orizzontali è stata affiancata quella relativa al fenomeno di “spanciamento” particolarmente evidente su uno dei quattro lati. Le scelte adottate per l’esecuzione del rilievo e l’estrazione delle informazioni hanno permesso un’analisi limitata allo stato di fatto; in futuro verranno messe in campo strategie atte a permettere la ripetibilità nel tempo delle misure e delle successive analisi, al fine di porre le basi per un monitoraggio strutturale. A tale scopo, sarà necessario sperimentare un’adeguata e proficua integrazione tra differenti tecniche e strumentazioni, inquadrando tutte le future sperimentazioni e misure nel medesimo sistema di riferimento assoluto. ABSTRACT: AbstractTerrestrial Laser Scanning Technology (TLS) allows to obtain the overall three-dimensional model of the investigated object with high accuracy. For this reason, such a technology is now increasingly applied in architecture as well. However, strongly fundamental is the choice of the most appropriate approach depending on the type of the object and the final purpose of the survey. Both the choice of the most suitable instrumentation and the use of specific data processing strategies are of concern.This paper aims to test the use of TLS for studying structures with high value from architectural and cultural points of view: Asinelli Tower and Garisenda Tower (located in Bologna-Italy). Both structures require to be carefully analyzed for controlling stability because of their dominant vertical dimension along with their significant slenderness. Those details make them particularly315Atti 15a Conferenza Nazionale ASITA - Reggia di Colorno 15-18 novembre 2011sensitive. The survey was performed with a time-of-flight (pulsed laser) laser scanner and resulted in the overall model of the structure with sub-centimeter resolution. For the Asinelli Tower, the goal was the identification of general information about the geometry of the structure such as the height of the tower, the development of its longitudinal axis and its overhang. Furthermore, for the Garisenda Tower, the analysis was mainly focused on the selenitic area located at the base of the Tower: both the geometry of horizontal sections and the phenomenon of the "belly flops" were investigated. This last one is particularly evident on the East side.All the analyses allowed to extract information about the actual geometry and attitude of the structure at the present. Strategies t

2010 - Adjustment and transformation strategies of ItalPoS Permanent GNSS Network [Articolo su rivista]
Castagnetti, Cristina; Casula, Giuseppe; Capra, Alessandro; Bianchi, Maria Giovanna; Dubbini, Marco
abstract

A private network of 133 GNSS (Global Navigation Satellite Systems) permanent sites, named ItalPoS (Italian Positioning Service) and covering quite uniformly the entire Italian territory, was established since April 2006 by the Italian Division of Leica Geosystems S.p.A. This network involves also several GPS stations of the INGV (Italian National Institute of Geophysics and Volcanology) RING (Real-time Integrated National Gps) network and GPS stations from other public and private administrations. The purpose of ItalPoS network is mainly the GNSS data distribution in terms of real time corrections and RINEX files for the post-processing. In order to compute and distribute to private and scientific users a set of adjusted coordinates of the ItalPoS network in the IGS05 and ETRF89-ETRF2000 (European Terrestrial Reference Frame) reference frames, a dataset of RINEX (Receiver INdependent EXchange) of 133 GPS permanent sites was created and processed, using the distributed sessions approach, by means of Gamit/Globk 10.3 GPS data processor, using also some SOPAC (Scripps Orbit and Permanent Array Center) and EUREF (Reference Frame Sub Commission for Europe) solutions to improve the reference frame definition and the internal constraint. All the strategies adopted to estimate coordinates and velocities of the ItalPoS Network in IGS05 will be described together with the investigated approaches to provide coordinates in ETRF89-ETRF2000 reference frames: in this case both Helmert and Boucher-Altamimi transformations were taken into account, the whole Italian territory was divided into three parts in order to optimize transformation residuals. Particular attention was paid to transition areas.

2010 - GPS-Aided Land-Based Navigation and Precision Farming Applications: Improving GPS Solutions by Means of MEMS-IMU and Low-Cost Sensors [Relazione in Atti di Convegno]
Castagnetti, Cristina; Biagi, Ludovico; Capra, Alessandro
abstract

The land-based navigation, paying attention to precision farming, is the research topic: the final purpose is the design and development of a guidance-aided system focusing on a lew-cost GPS receiver able to provide a pseudorange-based solution only. Specific tests have been carried out to perform the particular trajectories followed by the vehicle in agricultural applications, whose accuracy target is typically 1 m. Results show that the low-cost receiver is affected by a drift in time which is mainly detected while turning and causing a deviation from the optimal reference solution. Thus, the goal is to correct this behaviour because the deviation accumulates during time and causes a not optimal treatment of the field (waste of material and money). Paying attention to the cost of the system, a new idea was proposed: the integration between the low-cost GPS with a magnetometer/digital compass. A dedicated algorithm was also implemented, taking the heading provided by the magnetometer and using it to correct the deviation in rums. Unluckily a magnetometer is deeply influenced by ferrous materials and the sensor is supposed to be installed on the vehicle, which is mainly made by metal. As a consequence, the sensed measurements are affected by a deviation from the actual magnetic field. Those disturbances need to be properly reduced by an autocalibration procedure. First of all, this paper deeply analyzes the performances of those particular low-cost GPS receivers; furthermore a solution is presented by means of the integration with a magnetometer. Results will be shown with great attention to future developments and improvements of the low-cost system suggested for supporting the guidance in precision farming applications.

2010 - Il rilievo laser scanner 3D dell’insediamento di Montegibbio [Capitolo/Saggio]
Castagnetti, Cristina; Cielo, Roberto
abstract

Il contributo descrive il rilievo laser scanning 3D eseguito presso l'insediamento di Montegibbio e le successive elaborazioni dei dati volte a segmentare le porzioni appartenenti ad epoche diverse. Questa separazione digitale fornisce uno strumento utile agli studiosi che devono ricostruire le varie fasi abitatuive del sito.

2010 - Monitoraggio “near real time” di rischio frane: un GIS per la gestione dell’emergenza. [Relazione in Atti di Convegno]
Bertacchini, Eleonora; Castagnetti, Cristina; Capra, Alessandro; Dubbini, Marco; Boni, Emanuele
abstract

La presente ricerca è stata condotta nell’ambito del progetto PRIN07 “Rilievo e analisi multi- temporale in un Sistema di Informazioni Geo-spaziali per il monitoraggio dei movimenti e delle deformazioni di aree soggette a rischio territoriale” ed anche nell’ambito di convenzioni stilate con il Servizio Tecnico di Bacino degli affluenti del Po, sede di Modena. L’obiettivo del lavoro è la realizzazione di un Sistema di Informazioni Geo-spaziali (GIS) per la valutazione e la gestione del monitoraggio di aree soggette a rischio frane basato su misure provenienti da molteplici strumentazioni (topografiche e geotecniche).L’area test, la frana dei Boschi di Valoria, ubicata a Frassinoro (MO), è stata utilizzata come caso di studio sia per dimensioni sia per entità dei movimenti, particolarmente elevati in fase di acuta riattivazione (spostamenti fino a 10m al giorno). La caratteristica principale del sistema è la multidisciplinarietà, l’integrazione di molteplici approcci che diventano vicendevolmente i protagonisti da cui estrarre informazioni a seconda del lettore interessato: l’area è stata studiata con varie tecnologie, quali tecniche di posizionamento satellitare (GPS - Global Positioning System), stazione totale automatizzata, rilievi laser scanner da aereo (voli LiDAR - Light Detection And Ranging), strumentazione geotecnica (estensimetri, piezometri, inclinometri) e radar interferometrico terrestre (GB Sar - Ground Based Sinthetic aperture radar). Avere a disposizione una tale mole di dati è certamente una condizione invidiabile, a patto che sia subordinata ad un’adeguata organizzazione della stessa, al fine di renderla fruibile e soprattutto rapidamente consultabile: si è deciso così di raccogliere e visualizzare il tutto in un GIS. E’ stata posta particolare attenzione alla modalità di aggiornamento del sistema, che dovrebbe essere visualizzabile quasi in tempo reale: dati provenienti dalla stazione totale robotizzata e dal GPS, in continua acquisizione in sito, devono essere resi disponibili e visibili agli organi competenti il prima possibile, in modo da permettere un efficace e rapido intervento in caso di eventi di una certa entità. Da questa necessità è nato il problema, che in un primo momento era sembrato banale, della georeferenziazione dei dati in pseudo real time: le misure in frana fatte dalla stazione totale e le posizioni calcolate dei prismi sono prodotte in un sistema locale, ma devono essere trasformate nel sistema ETRF2000 (European Terrestrial Reference Frame) per essere congruenti con quelle risultanti dai GPS rover posti in frana. Si aggiunge la necessità di trasformare tutto il database corrente in modo da sovrapporlo alla cartografia regionale, fornita in ED50 UTM* per l’Emilia Romagna. Il GIS realizzato può essere efficacemente preso in considerazione come strumento per la pianificazione e la gestione di situazioni di emergenza a seguito di eventi di disastro causati da fenomeni di dissesto idrogeologico (frane).251Atti 14a Conferenza Nazionale ASITA - Brescia 9-12 novembre 2010Abstract (English version)The research is included in the PRIN07 project -Multi-temporal surveying and analysis in Geo- spatial Information System for monitoring areas subject to landslide risk-. The final purpose is the design and implementation of a GIS (Geographic Information System) focused on landslides monitoring based on multiple technologies.The case study is the Valoria landslide, located in Frassinoro (Modena, Italy), which was chosen as test site both for its largeness and for considerable displacements detected during the re-activation (10 m/day). The main feature of this system is the integration of multiple and different approaches and technologies such as satellite-based positioning (GPS - Global Positioning System), automated total station, airborne laser scanner (LiDAR - Light Detection And Ranging), geotechnical instruments (extensometers, piezometers, inclinom

2010 - Structural analysis of the Ghirlandina Tower vertical displacements [Capitolo/Saggio]
Bertacchini, Eleonora; Capra, Alessandro; Castagnetti, Cristina; Dubbini, Marco; Boni, Emanuele
abstract

The paper deals with the subsidence monitoring in the monumental centre of Modena with particular attention to the structural consequences on the UNESCO site. High precision leveling campaigns have been carried out in Piazza Grande; the network measurements, the data processing and the results are deeply described along with the structural implications for the Ghirlandina tower.

2010 - Terrestrial Laser Scanner for Surveying and Monitoring Middle Age Towers [Relazione in Atti di Convegno]
Bertacchini, Eleonora; Boni, Emanuele; Capra, Alessandro; Castagnetti, Cristina; Dubbini, Marco
abstract

We had the opportunity to make surveying of some middle age towers located in Emilia Romagna region (Italy): Ghirlandina tower (Modena), “Della Sagra” tower (Carpi, Modena) , Asinelli tower (Bologna). Those towers are very interesting by architectural and artistic point of view; Ghirlandina and Asinelli are Cultural Heritage site of UNESCO.Terrestrial laser scanner (TLS) instrument has been used with an accuracy at 1 cm level in order to obtain good restitution in absolute coordinates, even with a precise topographic determination of GCP (Ground Control Points). Tridimensional restitution of the towers is here presented; we would like to point out the attention on the way that we use the TLS for enhancing the geometrical characteristics, particularly the height of the towers and the axis development that were determined through the trajectory of barycenter of transversal sections.The determination of actual geometry is essential for the study of the buildings and it is a first fundamental step for monitoring the towers.

2009 - Adjustment and transformation strategies of ItalPoS permanent GNSS network [Articolo su rivista]
Castagnetti, Cristina; Casula, Giuseppe; Dubbini, Marco; Capra, Alessandro
abstract

A private network of 133 Global Navigation Satellite Systems (GNSS) permanent sites, named ItalPoS (Italian Positioning Service) and covering quite uniformly the entire Italian territory, was established since April 2006 by the Italian Division of Leica Geosystems S.p.A. This network involves also several GPS stations of the INGV (Italian National Institute of Geophysics and Volcanology) RING (Real-time Integrated National Gps) network and GPS stations from other public and private administrations. Indeed Leica Geosystems contributed with its experience and its products to these networks which nowadays fulfill the national covering where there are no ItalPoS stations. For instance, the purpose of ItalPoS network is mainly the GNSS data distribution in terms of real time corrections and RINEX files for the post-processing.In order to compute and distribute to private and scientific users a set of adjusted coordinates of the ItalPoS network in the IGS05 and ETRF89-2000 reference frames, a dataset of RINEX of about 120 GPS permanent sites was created and processed, using the distributed sessions approach, by means of Gamit/Globk 10.3 GPS data processor, using also some SOPAC (Scripps Orbits and Permanent Array Center) and EUREF (European Permanent Network) solutions to improve the reference frame definition and the internal constraint.In this paper we describe all the strategies adopted to estimate coordinates and velocities of the ItalPoS Network in IGS05 and in ETRF89-2000 reference frames in the whole Italian territory.

2009 - Continuous monitoring of active earth flow by means of an integrated GPS-automatic total station approach [Articolo su rivista]
Corsini, A.; Capra, A.; Bertacchini, E; Borgatti, L.; Borghi, A.; Castagnetti, Cristina; Cervi, F.; Daehne, A.; Dubb Ini, M.; Leuratti, E.; Manzi, V.; Pellegrini, M.; Ronchetti, F.; Bonanno, C.; Piantelli, E.
abstract

The research deals with the integration of surface displacement measurements obtained using geodetic and topographic instruments such as GPS, automatic total station and inclinometer sensor in a large-scale active earth flow. The landslide, located in the northern Apennine of Italy, damaged roads and endangered houses during a sequence of reactivations in 2001, 2005 and 2007. Monitoring has been performed by means of: an automatic total station, coupled with inclinometer sensor, measuring about 40 prisms located in the landslide to a maximum distance of 1.650 km; one double-frequency GPS receiver connects in streaming by wireless communication with 4 single-frequency GPS in side the flow. Until December 2007 the monitoring network was operated with periodic static surveyings followed by the data post-processing; while since March 2008 the total station system and GPS were automated in order to allow continuous data acquisition and near-real-time data processing. The monitoring network has been able to cope with displacement rates ranging from millimetres to metres per day, a performance not achieved by borehole systems operated in the slope, such as in-place inclinometers, that were damaged when displacements exceeded some decimetres. The data so far collected, integrated with geomorphic, geologic and borehole data, allowed the complex spatial and temporal pattern of slope movements to be tracked and the relationships between rainfall pattern and acceleration-deceleration phases to be highlighted.

2009 - Densification of IGS/EPN by local permanent networks: results sensitivity with respect to the adjustments choices [Articolo su rivista]
Biagi, Ludovico; Caldera, Stefano; Sansò, Fernando; Capra, Alessandro; Castagnetti, Cristina
abstract

The paper describes the processing strategies experienced in dealing with GNSS permanent network. Particularly the choices for the adjustment of IGS and EPN network densification concerning the case of Puglia and Lombardia italian regions.

2009 - Integrated Surveying System for Landslide Monitoring, Valoria Landslide (Appennines of Modena, Italy) [Relazione in Atti di Convegno]
Bertacchini, Eleonora; Capitani, Andrea; Capra, Alessandro; Castagnetti, Cristina; Corsini, Alessandro; Dubbini, Marco; Ronchetti, Francesco
abstract

The research object is the study and prevention of landslide risk through the utilization of integrated surveying systems like GPS and Automatic Total Station (Robotic station).The measurements have been applied to Boschi di Valoria landslide, located on Appennines of Modena in the Northern Italy, which relatively large size, about 1.6 square km, required the use of both techniques. The system is made by Automatic Total Station, looking at 45 reflectors and a GPS master station, reference for three rovers on the landslide. In order to monitor "local" disturbing effects, a bi-dimensional clinometer has been applied on the pilaster where the total station is located. In a first periodically measurements were collected, while the system is now performing continuously. The system permitted to evaluate movements from few millimeter till some meters per day in most dangerous areas; the entity of the movements obliged to plan an alert system that was activated after a first phase of phenomenon study. Topographic measurements have been integrated with geotechnical sensors (inclinometers and piezometers) in a GIS for landslide risk management.

2009 - Misure topografiche di precisione per il monitoraggio in zone a rischio idrogeologico [Articolo su rivista]
Bertacchini, Eleonora; Capra, Alessandro; Castagnetti, Cristina; Dubbini, Marco
abstract

L'articolo descrive una sperimentazione di strumentazione integrata in acquisizione periodica e successivamente continua per il monitoraggio del dissesto idrogeologico.

2009 - Stazione totale per il monitoraggio Leica TM30: test di verifica secondo norme DIN-18723 e test di funzionamento per il monitoraggio frane [Relazione in Atti di Convegno]
Bertacchini, E.; Boni, E.; Capitani, A.; Capra, A.; Castagnetti, C.; Corsini, A.; Dubbini, M.; Parmeggiani, E.
abstract

2008 - GPS navigation for precision farming [Relazione in Atti di Convegno]
Biagi, Ludovico; Capra, Alessandro; Castagnetti, Cristina; Dubbini, Marco; Unguendoli, Francesco
abstract

Precision farming, sometimes called site-specific agriculture, is a strategic task for agriculture: indeed it has the potential to reduce costs through more efficient and effective applications of crop inputs; it can also reduce environmental impacts by allowing farmers to apply inputs only where they are needed at the appropriate rate. Precision farming requires the use of new technologies, such as GPS, environmental sensors, satellites or aerial images and GIS to asses and understand variations. The present research deals with potentialities and limits of GPS for navigation in agricultural applications. GPS needs for farming applications are: − low cost in order to allow farmers to buy GPS technologies; −high precision in order to reduce the use of pesticides and fertilizers by means of an exact track. At first, static and kinematic tests have been performed, simulating the typical behaviour of an agricultural vehicle and usingdifferent kinds of GPS receivers and navigation softwares; the experimental results are presented: particularly, advantages and disadvantages of the popular Kalman filtering on trajectories are discussed. Starting from the analyses of the previous results, and taking into account the typical user requirements, a preliminary design for a new prototype has been done; particularly, both needed instrumentations and their costs and a proposal of a new navigation algorithm will be presented.

2007 - Agricoltura di precisione:l'aiuto del GPS nella guida dei veicoli [Relazione in Atti di Convegno]
Biagi, L.; Capra, A.; Castagnetti, C.; Dubbini, M. Unguendopli F.
abstract

2007 - Il servizio di posizionamento GNSS per la regione Puglia [Relazione in Atti di Convegno]
Biagi, L.; Capra, A.; Castagnetti, C.; Caroppo, T.; Muschitiello, M.; Beallanova, A.; Galeandro, A.
abstract