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Stefano CATTINI

Ricercatore t.d. art. 24 c. 3 lett. B presso: Dipartimento di Ingegneria "Enzo Ferrari"


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Pubblicazioni

- DEVICE CONNECTABLE TO A MACHINE FOR EXTRACORPOREAL TREATMENT OF THE BLOOD OF A PATIENT [Brevetto]
Carletti, Umberto; Cattini, Stefano; Lodi, Lorenzo; Lugli, Lorenzo; MAZZA CARLO, Martino; Meglioli, Davide; Rovati, Luigi
abstract

A device connected to a machine (29) for extracorporeal treatment of blood of a patient comprises a sensor element (17) positionable on the patient's body for detecting the electrical potential (VI) of the blood in the patient's body and varying means (18) for modifying the electrical potential of blood treated by said machine (29), the varying means (18) being so programmed as to make the difference between the electrical potential (V2) of the blood exiting said machine (29) and the electrical potential (VI) measured by the sensor element (!7) lower than present value.


- dispositivo collegabile ad una macchina per il trattamento extracorporeo del sangue di un paziente [Brevetto]
Carletti, Umberto; Cattini, Stefano; Lodi, Lorenzo; Lugli, Lorenzo; MAZZA CARLO, Martino; Meglioli, Davide; Rovati, Luigi
abstract

L’invenzione concerne un apparato per trattare il sangue20 di un paziente al di fuori del corpo umano,particolarmente un apparato per la circolazioneextracorporea, ossia un apparato che consente ditrattare il sangue di un paziente al di fuori del corpodel paziente stesso esercitando temporaneamente la25 funzione di propulsione circolatoria normalmenteesercitata dal cuore e la funzione di ossigenazionenormalmente esercitata dai polmoni.


2020 - Comparison of the VLP-16 LiDAR system with an absolute interferometer [Relazione in Atti di Convegno]
Cattini, S.; Rovati, L.; Di Cecilia, L.; Ferrari, L.
abstract

Many new technologies for ADAS are emerging in recent years. In this scenario, LiDARs are becoming one of the pillars for environmental sensing needed in ADAS.Driven by the automotive industry, nowadays many new manufacturers are continuously putting new LiDAR systems on the market, thus increasing LiDARs availability and concomitantly reducing prices. As a result, LiDARs are today finding many new applications in fields such as agriculture and industrial automation.In this paper, we describe and discuss a measurement procedure for the analysis of the performances of LiDARs and, we report the results obtained from the characterization of one the most widespread LiDAR systems -namely VLP 16 by Velodyne. In particular, we compare the estimates provided by the LiDAR with the estimates provided by an absolute interferometer. To the best of our knowledge, these are the first published data obtained comparing a LiDAR and an absolute interferometer.The proposed tests investigated both warm-up and stability and, errors in the measured coordinates.The obtained results indicate a warm-up times of about 42 min and errors of few millimeters over a measuring interval of about (2, 21) m.


2020 - Optical characterization of the beams generated by 3D-LiDARs: proposed procedure and preliminary results on MRS1000 [Articolo su rivista]
Cattini, Stefano; Di Cecilia, Luca; Ferrari, Luca; Rovati, Luigi
abstract


2020 - Performances and robustness of a fluorescent sensor for nearly-neutral pH measurements in healthcare [Articolo su rivista]
Cattini, Stefano; Truzzi, Stefano; Accorsi, Luca; Rovati, Luigi
abstract


2019 - On the feasibility of Absolute Distance Measurement by using Optical-Feedback into a Superluminescent Diode Cavity [Articolo su rivista]
Rovati, Luigi; Di Cecilia, Luca; Cattini, Stefano
abstract

The development of accurate absolute distance interferometers is a long-term research goal. The key impact of this paper is the demonstration of an absolute distance interferometer based on the optical-feedback into a superluminescent diode cavity. Thanks to the optical-feedback, we obtained huge interference fringes even with diffusive targets and without using high-sensitivity and low-noise detectors, but directly exploiting the monitor photodiode enclosed in the same package of the optical source. The low coherence of the optical source makes the system robust to any stray-light along the optical path and thus suitable to work in biological media and dusty industrial environments. The proposed signal processing exploits a zero-crossing approach to determine the absolute target position. Preliminary results show a 95% expanded uncertainty to measuring interval ratio of about 60 ppm over a measuring interval of 50 mm.


2019 - Optical feedback into a superluminescent diode cavity for absolute distance measurements [Relazione in Atti di Convegno]
Rovati, L.; Cecilia, L. D.; Cattini, S.
abstract

The development of accurate absolute distance interferometers is a long-term research goal. The key impact of this paper is the development of an absolute distance interferometer based on the optical feedback into a superluminescent diode cavity. The proposed approach employs a two arms interferometer feeds by a superluminescent diode. Thanks to the optical feedback, we obtained huge interference fringes even with diffusive targets. The proposed signal processing exploits a zero-crossing approach to determine the absolute target position. Preliminary results show a ratio between measurement uncertainty and range of about 50 ppm.


2018 - Fluorescence pH Sensor Based on Polymer Film [Relazione in Atti di Convegno]
Rovati, L; Cattini, S; Fabbri, P; Ferrari, L
abstract

Modern flexible circuit systems can include sensing elements. In this paper, possible implementation of a fluorescence pH sensor suitable for measurement of near neutral solution based on a polymer film is presented. Polymer films can satisfy the requests of the modern flexible systems, such as miniaturization, flexibility and enhanced sensitivity, allowing high performance sensing at low cost. Design, development and performance evaluation of the sensor are presented.


2017 - An improved optical scheme for self-mixing low-coherence flowmeters [Relazione in Atti di Convegno]
DI CECILIA, Luca; Rovati, Luigi; Cattini, Stefano
abstract

In this paper we present a fiber-based low-coherence self-mixing interferometer exploiting a single-arm approach to measure the flow in a pipe. The main advantages of the proposed system are the flexibility offered by fiber-connected optical head, a greater ease of alignment, the rejection of “common-mode” vibrations, and greater stability. Thanks to the use of a low-coherence source, the proposed system investigates the velocity of the scattering particles owing only in a fixed and well defined region located close to the duct wall itself. The reported experimental results demonstrate that in laminar flow regime the developed system is able to determine the flow and it is quite robust to variation in the scatterers concentration. Increasing the scatterers concentration of about 24 times, the sensitivity S has reduced of less than 30%. © (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.


2017 - On the feasibility of a CENTA-based biosensor to measure antibiotics concentration in milk [Relazione in Atti di Convegno]
Ferrari, Luca; Rovati, Luigi; Costi, Maria Paola; Venturelli, Alberto; Luciani, Rosaria; Cattini, Stefano
abstract

In veterinary practice antibiotics are used and abused all over the world both to treat diseases and prevent infections and, to increase feed efficiency thus promoting growth in food producing animals. With more than 30 years history, β-lactam antibiotics are nowadays one of the most important group of antibiotics in veterinary medicine. In this paper we investigate the possibility to realize a measurement method suitable for field testing and we propose a competitive biosensor based on a relatively low-cost chromogenic cephalosporin (CENTA) for the quantitative analysis of β-lactams concentration in milk. In particular, the reported preliminary study has been focused on cloxacillin and the reported results indicates that the method is potentially able to detect cloxacillin at a concentration of about one order of magnitude lower than the maximal residue limits (MRL) set by the European Commission.


2017 - Single-arm Self-mixing Superluminescent Diode Interferometer for Flow Measurements [Articolo su rivista]
DI CECILIA, LUCA; CATTINI, Stefano; GIOVANARDI, FABIO; ROVATI, Luigi
abstract

Laser-diode self-mixing interferometry is a noncontact technique widely used both in industries and laboratories. In this paper we propose to extend the self-mixing approach to low-coherence sources such as superluminescent diodes. In particular, we present a fiber-based common-path interferometer exploiting a single mode pigtailed super-luminescent diode. The developed measuring system has been demonstrated to be able to directly measure the flow in pipes. To the best of our knowledge, it is the first time that flow measurements have been performed by a single-arm self-mixing pigtailed super-luminescent-diode. The measuring system exploits the Doppler interference pattern produced by the light back-reflected from the inner facet of the pipe wall and the light back-diffused by the moving particles. Then, the use of a low-coherence source allows to measure the velocity of the scattering particles in a fixed and well defined region located close to the pipe wall, thus providing good robustness to variations of scatterers concentration and allowing to easily estimate the flow under the laminar flow assumption. Experimental results demonstrated a high linearity (Pearson coefficient of about 99%) and sensitivity of about 16.62±1.1 cm−3, with flows ranging from 1 cm3/s to 15 cm3/s and scatterers volume concentration ranging from 0.015% to 0.36%.


2016 - A simple calibration method to quantify the effects of head movements on vision-based eye-tracking systems [Relazione in Atti di Convegno]
Cattini, Stefano; Rovati, Luigi
abstract

A simple method for the calibration of eye-tracking systems based on eye-features detection is proposed. Many eye-tracking systems are claimed to be robust to head movements in some degree, but such robustness is rarely fully quantified. Moving chin-rest and synthetic images have been proposed to investigate head movements. However, both methods have several limitations. The reported calibration method exploits for the first time ocular imaging eye models (OIEMs) in order to simulate the eye(s), thus allowing to easily investigate the effects due to head movements. Moreover, it can be useful for the development and comparison of eye-tracking hardware, software and whole systems. Differently from human subjects, OIEMs are standardized and time-invariant thus, comparisons can be performed at different times and places, leading OIEMs to be a potential gold standard test for eye-tracking systems. Preliminary verification performed on a basic eye tracking system corroborate the applicability of described method.


2016 - An Optical Technique for Real-Time Monitoring of Hemolysis During Hemodialysis [Articolo su rivista]
Cattini, Stefano; Rovati, Luigi
abstract

Hemolysis--the lysis of red blood cells (RBCs) causing the release of free hemoglobin (Hb) into the patient's blood--is an unavoidable side effect of any extracorporeal circulation. If not promptly detected, hemolysis and the consequent free Hb can lead to severe health risks for the patient, such as thrombosis, compromised oxygen-carrying capacity that may cause injury to the brain and other organs, and, ultimately, the death of the patient. Accurate measurement methods to detect Hb have been known for a long time. However, such methods generally exploit toxic chemicals and/or are unable to distinguish the deleterious free Hb from the Hb contained inside intact RBCs; thus they are unsuitable for inline monitoring of the extracorporeal circulation. In this paper, a simple measurement method and a measuring system for early detection of hemolysis in hemodialysis (HD) are described. The developed measuring system performs an optical analysis of the dialysis fluid in order to estimate the free Hb concentration in the blood returned to the patient, thus potentially allowing for the first time the real-time and in-line quantitative monitoring of hemolysis in HD. Moreover, the noncontact features of the proposed technique and its analyses of the waste of the hemodialyzer allow both overcoming several issues related to biological risk in medical devices and easy integration into hemodialyzers already in use. Only vast clinical trials may be able to reasonably provide a significant estimation of the achievable measurement uncertainty. Nevertheless, the reported preliminary ex vivo experiments show that hemolysis can be detected with resolution and sensitivity potentially sufficient to reduce risks for patients.


2016 - Light-storing photocatalyst: The possibility of activating titanium dioxide by photoluminescence [Articolo su rivista]
Cattini, Stefano; Bondioli, Federica
abstract

Introduction: The aim of the present work was to analyze the possibility of creating a light-storing photocatalyst material, a system that couples a phosphorescent substrate with a titania coating. The substrate could activate the titanium dioxide coating even in condition of darkness thanks to its light emission. This improvement of absorption can be achieved because the titania semiconductor is irradiated both by the direct light and by the luminescent substrate which is activated at the same time. Methods: TiO2-based sol-gel solutions were deposited on commercial borosilicate glasses containing 2 different phosphorescent pigments (emission peaks at 470 and 520 nm, respectively). Particular attention was paid to optimize the film-substrate adhesion by using a scratch test to evaluate the optimal temperature of the posttreatment step. Results and discussion: The main result is that when irradiated the photoluminescent pigments allow an increase in the photocatalytic acitivity of the coatings. The pigments are able to convert the ultraviolet component of light in order to increase the amount of energy that can be absorbed by titania. Moreover, the hydrophilicity test showed that in the absence of irradiation the phosphorescent samples are characterized by a lower loss of superhydrophilicity.


2016 - Measuring haemolysis in haemodialysis: Comparison between a new and existing data processing algorithms [Relazione in Atti di Convegno]
Cattini, Stefano; Rovati, Luigi
abstract

Acute haemolysis in haemodialysis is a relatively rare complication, but it can lead to life-threatening issues up to the death of the patient. Due to the lack of measurement methods able to provide a realtime and in-line measurement of the haemolysis in extracorporeal circulation, in current medical practice the haemolysis level is not monitored during haemodialysis. In last two years we proposed a measurement method capable to measure in-line and in real-time the haemolysis level during haemodialysis. Such method is based on the estimation of the filter permeability to haemoglobin. To estimate the filter permeability we proposed two data processing algorithms: one simplified algorithm supposing constant permeability and the other supposing the filter permeability to be a linear function of the time integral of the filtered volume of solvent. However, the constant permeability algorithm is reasonably prone to errors, whereas the algorithm based on the time integral of the solvent volume does not allow the integration of the developed measuring system with hemodialyzers already in use. To overcome such limitation, in this paper we propose a new data processing algorithm based on the time integral of the mass of filtered haemoglobin. Such quantity can be easily estimated by the measuring system, allowing straightforward integration with hemodialyzers already in use. The performed experimental activities indicate as the new data processing algorithm is reasonably able to provide performance equal or better than the previous data processing algorithms.


2016 - Morphology evolution of gold nanoparticles as function of time, temperature, and Au(III)/sodium ascorbate molar ratio [Articolo su rivista]
Priolisi, Ornella; Fabrizi, Alberto; Deon, Giovanna; Bonollo, Franco; Cattini, Stefano
abstract

Abstract: In this work the morphology evolution of Au nanoparticles (AuNPs), obtained by direct reduction, was studied as a function of time, temperature, and Au(III)/sodium ascorbate molar ratio. The NPs morphology was examined by transmission electron microscope with image analysis, while time evolution was investigated by visible and near-infrared absorption spectroscopy and dynamic light scattering. It is found that initially formed star-like NPs transform in more spheroidal particles and the evolution appears more rapid by increasing the temperature while a large amount of reducing agent prevents the remodeling of AuNPs. An explication of morphology evolution is proposed. Graphical Abstract: [Figure not available: see fulltext.]


2016 - Near-infrared spectroscopy for non-invasive monitoring of drugs blood-brain barrier penetration [Relazione in Atti di Convegno]
Rovati, Luigi; Cattini, Stefano; Crespi, Francesco
abstract

In this paper, a near-infrared spectroscopy instrument adapted for in-vivo NIRS measurements of rodent's brain is presented. This prototype was designed for non-invasive analysis of the two main forms of hemoglobin: oxy-hemoglobin and deoxy-hemoglobin. These two chromophores are markers of the degree of tissue oxygenation, thus providing an index of blood levels and therefore of brain metabolism. This information can be profitably used for non-invasive monitoring the ability of drugs to penetrate the blood-brain barrier. The preliminary experimental activity denotes an original relationship between NIRS analysis of brain blood metabolism and drugs effect.


2015 - A simple measuring system and calibration method to investigate light transmission ability of light-transmitting fiber posts [Relazione in Atti di Convegno]
Cattini, Stefano; Rovati, Luigi
abstract

Light-transmitting fiber posts are recognized to potentially improve the cements polymerization, thus potentially improving the bonding of the endodontics restoration. However, different posts generally have completely different light transmission, hence it is important to be able to compare their optical performances. In this paper a simple measuring system able to compare the exitance generate by different light-transmitting fiber posts is proposed. The described measuring system is based on a microscope and a digital camera coupled to its optics. A simplified calibration and a detailed measurement procedure are described and investigated. Then, data obtained from the analysis of some commercial light-transmitting fiber posts are reported and briefly discussed. Even though, mechanical properties, biocompatibility and aesthetics have to be taken into account once choosing the post, the data provided by the proposed measuring system may support in choosing the post and, defining the proper light-source power and exposure duration.


2015 - Design and performance of an Hb measuring system: Viability of its use in a haemodialysis [Relazione in Atti di Convegno]
Cattini, Stefano; Rovati, Luigi
abstract

Haemolysis is an unavoidable side effect of any extracorporeal circulation. If not promptly detected, haemolysis can lead to severe health risks for the patient such as thrombosis, compromised oxygen-carrying capacity that may cause injury to the brain and other organs, and, ultimately, a cardiac arrest.


2015 - In vivo real time non invasive monitoring of brain penetration of chemicals with near-infrared spectroscopy: Concomitant PK/PD analysis [Articolo su rivista]
Crespi, Francesco; Cattini, Stefano; Donini, Maurizio; Bandera, Andrea; Rovati, Luigi
abstract

Background. Near-infrared spectroscopy (NIRS) is a non-invasive technique that monitors changes in oxygenation of haemoglobin. The absorption spectra of near-infrared light differ for the oxygenation–deoxygenation states of haemoglobin (oxygenate (HbO2) and deoxygenate (Hb), respectively) so that these two states can be directly monitored. Comparison with existing method(s). Different methodologies report different basal values of HbO2 and Hb absolute concentrations in brain. Here, we attempt to calculate basal HbO2 levels in rat CNS via evaluation of the influence of exogenous oxygen or exogenous carbon dioxide on the NIRS parameters measured in vivo. New method. Furthermore the possibility that changes of haemoglobin oxygenation in rat brain as measured by NIRS might be a useful index of brain penetration of chemical entities has been investigated. Different compounds from different chemical classes were selected on the basis of parallel ex vivo and in vivo pharmacokinetic (PK/PD) studies of brain penetration and overall pharmacokinetic profile. Results. It appeared that NIRS might contribute to assess brain penetration of chemical entities, i.e. significant changes in NIRS signals could be related to brain exposure, conversely the lack of significant changes in relevant NIRS parameters could be indicative of low brain exposure. Conclusions. This work is proposing a further innovation on NIRS preclinical applications i.e. a “chemical” NIRS [chNIRS] approach for determining penetration of drugs in animal brain. Therefore, chNIRS could became a non invasive methodology for studies on neurobiological processes and psychiatric diseases in preclinical but also a translational strategy from preclinical to clinical investigations.


2014 - A simple and robust optical scheme for self-mixing low-coherence flowmeters [Relazione in Atti di Convegno]
Cattini, Stefano; Rovati, Luigi
abstract

The developed measuring system is based on a low-coherence source and a self-mixing (or inter- nal) detection. The proposed optical layout exploits the reflection from the internal wall of the duct as reference arm, thus reducing system complexity, cost, size and increasing its robustness to movements of the measurand. Moreover, the usage of a low-coherence source allows reducing the problems related to the poor definition of the volume under test (sensing region or measurement volume) typical of “coherent” self-mixing systems. Although preliminary analysis have been performed by simply investigating the frequencies rel- ative to the maximum in the Doppler spectrum, the obtained results demonstrates that by in- creasing scatterers concentration of +300%, the system sensitivity increases of about only +20%.


2014 - A simple measuring system for early detection of haemolysis during haemodialysis [Relazione in Atti di Convegno]
Cattini, Stefano; Rovati, Luigi; M., Bernabei; D., Cianciavicchia; P., Monari; A., Sicuri
abstract

A simple measuring system for early detection of haemolysis during haemodialysis is proposed. The developed measuring system performs an optical absorption spectroscopy analysis of the dialysis fluid in order to estimate the free haemoglobin concentration in the blood returned to the patient-the potential cause of injury for the patient. The integration of the developed measuring system into hemodialyzers results simple and relatively inexpensive (overall system cost is about few hundred dollars). Preliminary results confirm the applicability of the proposed measuring system.


2014 - An in vitro model of a system of electrical potential compensation in extracorporeal circulation. [Articolo su rivista]
Carletti, U.; Cattini, Stefano; Lodi, Renzo; Petralia, A.; Rovati, Luigi; Zaffe, Davide
abstract

OBJECTIVES: Extracorporeal circulation (ECC) in patients undergoing cardiac surgery induces systemic immune-inflammatory reaction that results in increased postoperative morbidity. Many factors are responsible for the adverse response after ECC. The present in vitro study aimed to investigate electric charges (ECs) generated during ECC, to set a device compensating the ECs, and checking its effect on red blood cells (RBC).; MATERIALS AND METHODS: The electrical signals of blood in ECC were collected by a custom developed low-noise electronic circuit, processed by a digital oscilloscope (DSO) and a dynamic signal analyzer (DSA). The compensation of ECs was performed using a compensation device, injecting a nulling charge into the blood circuit. The compensation effect of the ECs on RBCs was evaluated by scanning electron microscope (SEM).; RESULTS: The electrical analysis performed using both the DSO and the DSA confirmed the EC formation during ECC. The notable electric signals recorded in standard ECC circuits substantially nulled once the compensation device was used, thus confirming efficient EC compensation. After two hours of ECC, the SEM non-blended test on human RBC samples highlighted morphological changes in acanthocytes of the normal biconcave-shaped RBC.; CONCLUSIONS: The outcomes confirm the development of parasitic ECs during ECC and that a suppressor system may decrease the potential damage of ECs. Nevertheless, further studies are ongoing in order to investigate the complex mechanisms related to lymphocytes and platelet morphological and physiological chances during triboelectric charges in ECC.


2013 - Development of a Sensor System for the Determination of Sanitary Quality of Grapes. [Articolo su rivista]
Zanardi, Chiara; Ferrari, Luca; Zanfrognini, Barbara; Pigani, Laura; Terzi, Fabio; Cattini, Stefano; Rovati, Luigi; Seeber, Renato
abstract

An instrument for the automatic quantification of glycerol in grapes has been developed. We verify here that this analyte can be taken as a benchmark of a serious disease affecting the grapevines, namely Botrytis cinerea. The core of the instrument is an amperometric biosensor consisting of a disposable screen printed electrode, generating the analytical signal thanks to a bi-enzymatic process involving glycerol dehydrogenase and diaphorase. The full automation of the analysis is realised by three micropumps and a microprocessor under control of a personal computer. The pumps allow the correct and constant dilution of the grape juice with a buffer solution also containing [Fe(CN)6]4- redox mediator and the injection of NAD+ cofactor when the baseline signal reaches a steady state; the instrument leads to automated reading of the analytical signal and the consequent data treatment. Although the analytical method is based on an amperometric technique that, owing to heavy matrix effects, usually requires an internal calibration, the analyses indicate that a unique external calibration is suitable for giving accurate responses for any grapes, both white and black ones.


2013 - In vivo diffuse correlation spectroscopy investigation of the ocular fundus [Articolo su rivista]
Cattini, Stefano; Staurenghi, Giovanni; Gatti, Antonietta; Rovati, Luigi
abstract

Diffuse correlation spectroscopy (DCS) measurements in vivo recorded from rabbits' ocular fundus are presented. Despite the complexity of these ocular tissues, we provide a clear and simple demonstration of the DCS abilities to analyze variations in physiological quantities of clinical interest. Indeed, the reported experimental activities demonstrate that DCS can reveal both choroidal-flow and temperature variations and detect nano- and microaggregates in ocular fundus circulation. Such abilities can be of great interest both in fundamental research and practical clinical applications. The proposed measuring system can be useful in: (a) monitoring choroidal blood flow variations, (b) determining the end-point for photo-dynamic therapy and transpupillary thermo therapy and, (c) managing the dye injection and determining an end-point for dye-enhanced photothrombosis. Moreover, it could allow both diagnoses when the presence of nano- and micro-aggregates is related to specific diseases and verifying the effects of nanoparticle injection in nanomedicine. Even though the reported results demonstrate the applicability of DCS to investigate ocular fundus, a detailed and accurate investigation of the limits of detection is beyond the scope of this article. © 2013 Society of Photo-Optical Instrumentation Engineers.


2012 - A Novel Method for Noninvasive Monitoring of Ocular Fundus Status During Transpupillary Thermotherapy Treatment [Articolo su rivista]
Cattini, Stefano; Rovati, Luigi
abstract

A novel optical method for noninvasive monitoring of the ocular fundus status is presented. The method could provide an optimal end-point for transpupillary thermotherapy treatment, thus overcoming the severe over- and under-treatment issues currently affecting about 10% of patients. The developed instrument and measurement procedure have been tested on both a mechanical eye model and animal models. The presented results demonstrate the ability of our system to potentially detect variations in both blood flow and optical properties. Much more work will be needed before the developed instrument will be ready for clinical test, nevertheless the proposed method may provide an important improvement in the treatment of several disabling ocular diseases.


2012 - A simple measuring system for automotive damper wear estimation [Relazione in Atti di Convegno]
L., Ferrari; Cattini, Stefano; Rovati, Luigi; A., Bosi
abstract

A low-cost, portable and easy to use measuring system for the diagnosis of worn automotive dampers is proposed. The system is composed by two wireless sensing nodes equipped with MEMS accelerometers. The aim is to provide a measuring system which will yield comparable metrological performances, at a much lower cost than pre-existing systems.


2012 - Innovative ophthalmic instrument to detect nano- and micro-aggregates in blood circulation [Relazione in Atti di Convegno]
Rovati, Luigi; Cattini, Stefano; Salvatori, Roberta; Antonietta, Gatti
abstract

An ophthalmic instrument for innovative analyses of the eye microcirculation is presented. The developed system employs a laser source to performs the DWS (diffusing-wave-spectroscopy) analysis of the light intensity back diffused by the ocular fundus structures, thus allowing a noninvasive detection of changes and modulations of both optical and dynamical properties of blood flow. The reported preliminary experimental results recorded in-vivo on rabbits' ocular fundus, demonstrate the ability of the system to detect nano- micro-aggregates carried by the blood flow in the ocular fundus.


2012 - Low-Cost Imaging Photometer and Calibration Method for Road Tunnel Lighting [Articolo su rivista]
Cattini, Stefano; Rovati, Luigi
abstract

A camera-based measuring instrument for road tunnels lighting is proposed. The system is aimed at estimating the veiling luminance as it will be perceived by a driver approaching the tunnel, thus allowing the estimation of the optimum luminance level of tunnel entrances, hence increasing the driver's safety. The proposed measuring instrument and the relative calibration method are based on a low-cost commercial grade camera and a reference standard, respectively.


2012 - Toward the development of a low-cost laser Doppler module for ophthalmic microscopes [Relazione in Atti di Convegno]
Cattini, Stefano; Rovati, Luigi
abstract

A laser Doppler module easily integrated into a commercial ophthalmic microscope is proposed. Such setup adds flow measurement capability to standard visual inspection of the fundus. The proposed instrument may provide important clinical information such as the detection of vessel occlusion provided by surgical treatments (i.e. photocoagulation). The measuring system is based on a self-mixing laser diode Doppler flowmeter (SM-DF). Reduced costs, easy implementation and small size represent the main features of SM-DF. Moreover, this technique offers the advantage to have the excitation and measurement beams spatially overlapped, thus both overcoming the alignment difficulty of traditional laser Doppler flowmeter and, well fitting with to limited optical aperture of the pupil. Thanks to an on-board DSP-microcontroller, the optoelectronic module directly estimates the blood flow; USB connection and an ad-hoc developed user-friendly software interface allow displaying the result on a personal computer. Preliminary test demonstrates the applicability of the proposed measuring system.


2012 - Zero-Field Readout Electronics for Planar Fluxgate Sensors Without Compensation Coil [Articolo su rivista]
Rovati, Luigi; Cattini, Stefano
abstract

A simple and sensitive readout electronics for planar fluxgate sensors is presented. The system exploits the sense coils to directly generate the compensation static field avoiding the additional coil/s required in standard closed loop configuration, thus providing clear advantages in terms of size and cost. Moreover, feedback configurations are known to provide better linearity and stability of the system. The sensitivity of the developed demonstration system can be easily set from 13.3 to 104.9 mV/μT with nonlinearity ranging from 0.17% to 0.38% of the measuring interval, whereas the corresponding measuring intervals vary from ±301 to ±38 μT. The measuring uncertainty, the noise field spectral density, and the system bandwidth have been estimated in 12.2 nT, ≈ 10 nT/√{Hz}, and ≈1.5 Hz, respectively. The proposed measuring instrument is extremely easy to use and versatile. Moreover, due to the use of commercially available ferromagnetic material and the simple and via-less design, the proposed fluxgate sensor results in a very low cost and reliable device.


2011 - A low-cost system and calibration method for veiling luminance measurement [Relazione in Atti di Convegno]
Cattini, Stefano; Grana, Costantino; Cucchiara, Rita; Rovati, Luigi
abstract

A CCD-based measuring instrument aimed at the veiling luminance estimation and the relative low-cost calibration method are described. The system may allow the estimation of the optimum luminance levels in road-tunnels lighting, thus both increasing the drivers safety and avoiding energy wasting hence unjustified higher lighting-costs.


2011 - An optical method for the analysis of the exitance diffused by light-transmitting fiber post [Relazione in Atti di Convegno]
Cattini, Stefano; Rovati, Luigi
abstract

The paper is focused on the description of a measurement procedure and image analysis technique able to easily estimate the exitance diffused by light-transmitting posts. The exitance has been measured by making use of a digital colour camera (DP20, Olympus) coupled to the optics of a microscope (SZX12, Olympus). Posts have been illuminated by using: a blue LED source (LS-450 Blue LED, Ocean Optics) with emission peak close to camphorquinone activator peak, an optical fibre and an ad-hoc realized post holder. The obtained results demonstrate that different translucent posts give rise to different exitance profiles, thus allowing to reach different polymerization depths along the post, providing different polymerization performances and, requiring different source powers and exposure times. Even though, other factors such us mechanical performances, biocompatibility and aesthetics have to be consider once choosing the more suitable post, the reported measurement procedure and data may help both in choosing the proper post and defining the optimum light-source power and exposure time.


2011 - Measurement of the fluid-velocity profile using a self-mixing superluminescent diode [Articolo su rivista]
Rovati, Luigi; Cattini, Stefano; Palanisamy, Nithiyanantham
abstract

A novel optical Doppler velocimeter using a self-mixing superluminescent diode is proposedand demonstrated. The operation mechanism uses the photodiode on the back-face of acommercial superluminescent diode to detect the Doppler signal from an interferometer.Thanks to the low coherence length of the optical source, the position of the measuring volumecan be easily moved into the sample under test by adjusting the reference arm length, thusallowing us to measure the velocity profile of the flowing scatterers even in turbid media. Theproposed velocimeter is expected to have several industrial as well as medical applications.


2010 - Blood flow measurement in extracorporeal circulation using self-mixing laser diode [Relazione in Atti di Convegno]
Cattini, Stefano; Michele, Norgia; Alessandro, Pesatori; Rovati, Luigi
abstract

To measure blood flow rate in ex-vivo circulation, we propose an optical Doppler flowmeter based on the self-mixing effect within a laser diode (SM-LD). Advantages in adopting SM-LD techniques derive from reduced costs, ease of implementation and limited size. Moreover, the provided contactless sensing allows sensor reuse, hence further cost reduction. Preliminary measurements performed on bovine blood are reported, thus demonstrating the applicability of the proposed measurement method.


2010 - Contactless Two-Axis Inclination Measurement System Using Planar Flux-Gate Sensor [Articolo su rivista]
Rovati, Luigi; Cattini, Stefano
abstract

A tilt-sensitive measuring system exploiting a low-cost planar printed-circuit-board (PCB) flux-gate sensor is described. We propose a system topology that exploits two magnets and a flux-gate sensor to realize a two-axis tilt-sensitive measuring system. The sensing configuration has been investigated using electromagnetic modeling software first. Then, the prototype characterization has shown system sensitivity up to 4 V/° and integral nonlinearity (INL) down to 1%. Mainly limited by the mechanical implementation, the obtained system dynamic range is about ±3°.


2009 - Two-axis inclination measurement system based on a planar flux-gate sensor [Relazione in Atti di Convegno]
Cattini, Stefano; Rovati, Luigi
abstract

tilt-sensitive measuring system exploiting a low-cost planar printed-circuit-board (PCB) flux-gate sensor is described. We propose a system topology that exploits two magnets and a flux-gate sensor to realize a two-axis tilt-sensitive measuring system. The sensing configuration has been investigated using electromagnetic modeling software first. Then, the prototype characterization has shown system sensitivity up to 4 V/ð and integral nonlinearity (INL) down to 1%. Mainly limited by the mechanical implementation, the obtained system dynamic range is about ñ3ð.


2009 - UV-LEDs for monitoring dialysis adequacy [Articolo su rivista]
Rovati, Luigi; Cattini, Stefano
abstract

Abstract—New Ultraviolet (C band: 280 nm − 100 nm) lightemitting diodes (UV-C LEDs) have been characterized to evaluatetheir potential applicability in the development of a simple low–cost optical adequacy sensor for continuous online measurementson spent dialysate. This approach would allow us to avoid theuse of bulky and expensive spectrometers in the monitor systems.The reported results could be useful for the system developmenteven if different critical aspects such as LED reliability, meanlifetime, and emitted and transmitted power monitoring should betaken into consideration. Nevertheless, the experimental activityhas shown that the system can be implemented with few opticalcomponents and that the assembly can be made simple.


2008 - A simple readout electronics for automatic power controlled self-mixing laser diode systems [Articolo su rivista]
CATTINI, Stefano; ROVATI, Luigi
abstract

he paper describes a simple electronic circuit to drive a laser diode for self-mixing interferometry. The network integrates a stable commercial automatic power controller and a current mirror based readout of the interferometric signal. The first prototype version of the circuit has been realized and characterized. The system allows easily performing precise interferometric measurements with no thermostatic circuitry to stabilize the laser diode temperature and an automatic control gain network to compensate emitted optical power fluctuations. To achieve this result, in the paper a specific calibration procedure to be performed is described.


2008 - Measuring Dynamics of Scattering Centers in the Ocular Fundus [Articolo su rivista]
Rovati, Luigi; Cattini, Stefano; F., Viola; G., Staurenghi
abstract

The study is focused on the analysis of the diffusing-wave-spectroscopy signalrecorded invivo on the ocular fundus of a rabbit eye. The motion of the scattered sites wasmeasured as a function of the pressure exerted by a Goldmann contact lens and during themoderate temperature increase induced by a therapeutic laser diode. Temporal fluctuations ofthe signal revel motion of molecules and thus changes in tissues temperature andchorioretinal blood velocity. Experimental results show the ability of the system to detectmotion of the scattering sites in the ocular fundus layers during variations of the ocularpressure and laser heating.


2008 - On the use of deep UV-LEDs for monitoring dialysis [Relazione in Atti di Convegno]
Rovati, Luigi; Cattini, Stefano
abstract

The new UV-C LEDs have been characterized to evaluate their potential applicability in the development of a simple, low-cost optical adequacy sensor for continuous, on-line measurements on spent dialysate. This approach would allow us to avoid the use of bulky and expensive spectrometers in the monitor systems. The reported results could be useful for the system development; nevertheless, different critical aspects such as LEDs reliability, mean life time and emitted and transmitted power-monitoring should be taken in consideration.


2007 - Closed loop PCB Fluxgate without compensation coil [Relazione in Atti di Convegno]
Rovati, Luigi; Cattini, Stefano; Marchesi, M; Dallago, E.
abstract

We propose a circuit arrangement that exploits the sense coil of a planar PCB fluxgate to generate the compensation static field in the closed loop configuration. This approach allows to overcome the difficulties related to the optimization of the coupling efficiency between compensation and sense coil. Experimental results are presented to demonstrate the feasibility of the proposed approach.


2007 - In-vivo diffusing-wave-spectroscopy measurements of the ocular fundus [Articolo su rivista]
Rovati, Luigi; Cattini, Stefano; N., Zambelli; F., Viola; G., Staurenghi
abstract

We present what is to our knowledge the first observation of a diffusing-wave-spectroscopy signal recorded in-vivo on the ocular fundus. A modified ophthalmic microscope was developed which can acquire diffusing-wave-spectroscopy signal from the eye fundus. The diffusing-wave-spectroscopy signal was recorded in-vivo on a rabbit eye during transpupillary thermotherapy. Experimental results show the ability of the system to detect motion of the scattering sites in the ocular fundus layers during laser thermal heating. (c) 2007 Optical Society of America.


2007 - Measurement of the Retina and Choroid Diffusion Coefficients During TTT [Abstract in Rivista]
F., Viola; N., Zambelli; CATTINI, Stefano; D., Galimberti; R., Ratiglia; G., Staurenghi; ROVATI, Luigi
abstract

PurposeDiffusing-wave-spectroscopy (DWS) is a technique able to monitor microscopic movements in turbid media. In this study, we report the first observation of a DWS signal recorded in-vivo on the ocular fundus of a rabbit eye during a laser thermal treatment. MethodsA modified slit-lamp with a 30/70 beam splitter and a custom made fibers adapters including the collimation lenses, equipped with a standard therapy laser diode, was used. The motion of the scattered sites in the fundus was varied using transpupillary thermotherapy (TTT) for 60 seconds with a power settings of 200 mW. The scattered light was then guided by the single mode fiber to a single photon counting module (SPCM-AQR-14-FC, Perkin Elmer). The electrical signal from the SPCM was processed by a digital correlator (FLEX99S160B, Correlator.com) to acquire the normalized intensity autocorrelation function. Thus the APD photodiode was substituted by a HeNe laser in order to define the collection area. The distance between illumination and collection spots was estimated to be about 2 mm. Immediately before TTT, the APD photodiode was reconnected to the receiving fiber and three autocorrelation functions were acquired each 5 seconds. Next, we started the laser thermal treatment. During the 60-second NIR laser exposure, an autocorrelation functions was acquired each 5 seconds for a total of 12 readings. After the TTT three autocorrelation functions were acquired each 5 seconds. ResultsAutocorrelation functions exhibit a similar trend and a common plateau in the delay time range (200ms, 1000ms). The mean-squared displacements of the scattering sites in the short and long delay range were calculated for all the acquired autocorrelation functions. We fit a linear function to in the long delay range and a quadratic function in the short delay range, then we evaluated the diffusion coefficient of the scatterers in the retina and choroid layer. The values estimated at the different stages of the experiment show as in the retina the temperature induced a motion of the scatterers that increases monotonically during the treatment. The choroidal diffusion coefficient induced by the temperature elevation shows a very well defined sharp step-down. ConclusionsA correlation was found between DWS signal and motion of the scatterers on the ocular fundus, therefore this technique may be used to evaluate useful parameters during laser treatments.


2007 - Optical monitoring of the chorioretinal status during retinal laser thermotherapy [Relazione in Atti di Convegno]
Rovati, Luigi; Nicola, Zambelli; Cattini, Stefano; Francesco, Viola; Giovanni, Staurenghi
abstract

As a consequence of pigmentation inhomogeneities and/or different vascularizations of the retinal tissue, retinal laser thermo-treatments are often over- or underexposed. Our study is focused on the determination of suitable parameters to identify a convenient end-point of the laser treatment. The proposed method is based on the analysis of the temporal fluctuations of the scattered light intensity from the spot area. Motion of molecules and thus frequency of the scattered light fluctuations changes during the laser exposure due to variations of temperature, blood flow and optical parameters, i.e. absorption and scattering coefficient.


2007 - Self-mixing laser velocimeter for retinal blood flow measurements [Relazione in Atti di Convegno]
Cattini, Stefano; Giorgia, Salvatori; Rovati, Luigi
abstract

A Doppler velocimeter exploiting a self-mixing laser diode is proposed. The system has been design to evaluate the retinal blood flow velocity. The central frequency of the Doppler band obtained from the self-mixing laser diode measurement is related to the blood flow velocity in the vessel under test. The measurement can be done under the light-intensity feedback ratio below -100 dB without using highly sensitive electronics since the laser acts as a high-efficiency mixer oscillator and a shot-noise-limited quantum detector. The advantages in adopting such technique consist in its low cost, easiness of implementation and small size. Moreover, the self-mixing laser diode method offers the advantage to have the excitation and measurement beams spatially overlapped overcoming the alignment difficulty due to limited optical accessibility imposed by the finite aperture of the pupil.


2006 - HOLLOW BEAM GEOMETRY FOR DIFFUSING TEMPORAL LIGHT CORRELATION [Relazione in Atti di Convegno]
Rovati, Luigi; N., Zambelli; Cattini, Stefano; G., Salvatori
abstract

The paper presents an optical setup for diffusingtemporal light spectroscopy of living tissues. The systemallows to study the dynamical properties of living tissuesmolecules. The proposed approach exploits the hollow beamgeometry in conjunction to mode-selective detection. Firstexperiments, aimed to demonstrate the functionality of themeasuring system, have been performed.