The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform
Vittorio Murino - One of the best experts on this subject based on the ideXlab platform.
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Audio Tracking in Noisy Environments by Acoustic Map and Spectral Signature
IEEE Transactions on Cybernetics, 2018Co-Authors: Marco Crocco, Samuele Martelli, Andrea Trucco, Andrea Zunino, Vittorio MurinoAbstract:A novel method is proposed for generic target tracking by audio measurements from a microphone array. To cope with noisy environments characterized by persistent and high energy interfering sources, a classification map (CM) based on spectral signatures is calculated by means of a machine learning algorithm. Next, the CM is combined with the Acoustic map, describing the spatial distribution of sound energy, in order to obtain a cleaned joint map in which contributions from the disturbing sources are removed. A likelihood function is derived from this map and fed to a particle filter yielding the target location estimation on the Acoustic Image. The method is tested on two real environments, addressing both speaker and vehicle tracking. The comparison with a couple of trackers, relying on the Acoustic map only, shows a sharp improvement in performance, paving the way to the application of audio tracking in real challenging environments.
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three dimensional Image generation and processing in underwater Acoustic vision
Proceedings of the IEEE, 2000Co-Authors: Vittorio Murino, A TruccoAbstract:Underwater exploration is becoming more and more important for many applications involving physical, biological, geological, archaeological, and industrial issues. This paper aims at surveying the up-to-date advances in Acoustic acquisition systems and data processing techniques, especially focusing on three-dimensional (3-D) short-range imaging for scene reconstruction and understanding. In fact, the advent of smarter and more efficient imaging systems has allowed the generation of good quality high-resolution Images and the related design of proper techniques for underwater scene understanding. The term Acoustic vision is introduced to generally describe all data processing (especially Image processing) methods devoted to the interpretation of a scene. Since Acoustics is also used for medical applications, a short overview of the related systems for biomedical Acoustic Image for motion is provided. The final goal of the paper is to establish the state of-the art of the techniques and algorithms for Acoustic Image generation and processing, providing technical details and results for the most promising techniques, and pointing out the potential capabilities of this technology for underwater scene understanding.
Akira Asada - One of the best experts on this subject based on the ideXlab platform.
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automatic non destructive three dimensional Acoustic coring system for in situ detection of aquatic plant root under the water bottom
Case Studies in Nondestructive Testing and Evaluation, 2016Co-Authors: Katsunori Mizuno, Akira Asada, Xiaofei Liu, Yasufumi Fujimoto, Tetsuo Shimada, Fuyuki Katase, Makoto Murakoshi, Yasunobu Yagita, Yoshiaki WatanabeAbstract:Abstract Digging is necessary to detect plant roots under the water bottom. However, such detection is affected by the transparency of water and the working skills of divers, usually requires considerable time for high-resolution sampling, and always damages the survey site. We developed a new automatic non-destructive Acoustic measurement system that visualizes the space under the water bottom, and tested the system in the in situ detection of natural plant roots. The system mainly comprises a two-dimensional waterproof stage controlling unit and Acoustic measurement unit. The stage unit was electrically controlled through a notebook personal computer, and the space under the water bottom was scanned in a two-dimensional plane with the stage unit moving in steps of 0.01 m (±0.0001 m). We confirmed a natural plant root with diameter of 0.025–0.030 m in the reconstructed three-dimensional Acoustic Image. The plant root was at a depth of about 0.54 m and the propagation speed of the wave between the bottom surface and plant root was estimated to be 1574 m/s. This measurement system for plant root detection will be useful for the non-destructive assessment of the status of the space under the water bottom.
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application of a high resolution Acoustic video camera to fish classification an experimental study
IEEE International Underwater Technology Symposium, 2015Co-Authors: Katsunori Mizuno, Akira Asada, Xiaofei Liu, Jun Ashizawa, Yasufumi Fujimoto, Tetsuo ShimadaAbstract:In this study, we try for fish classification using high resolution Acoustic video camera at 3.0 MHz center frequency (ARIS). Newly observation method with wide in vertical and narrow in horizontal beam (WVNHB) was proposed for getting high quality Acoustic Image of swimming fish, and tested an Image processing algorithm basing on Normalized Cross Correlation (NCC) for fish classification. This high-frequency Acoustic video camera was applied to fish classification for the first time. Using the proposed observation method, we successfully obtained high quality Acoustic Images of fish and performed an Image processing algorithm on the Images.
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three dimensional mapping of aquatic plants at shallow lakes using 1 8 mhz high resolution Acoustic imaging sonar and Image processing technology
Internaltional Ultrasonics Symposium, 2014Co-Authors: Katsunori Mizuno, Akira AsadaAbstract:A new integrated measurement system that combines the Acoustic imaging sonar of DIDSON (Dual-frequency IDentification SONar) with concentrator lenses, motion sensors, and differential global positioning system (DGPS) was used to classify different species of aquatic plants and make three-dimensional (3D) mapping of them at shallow lake. In the field experiment at the Lake Yunoko, the Image was captured with a 3° concentrator lens. Difference of Gaussian (DoG) filtering was used to classify two species of aquatic plants, Chara globularis and Elodea nuttallii appeared in 2D Acoustic Images. After the classification, 3D Acoustic Image was reconstructed from the consecutive 2D processed Images. The high-resolution Acoustic Images obtained allowed us to identify individual aquatic plants with high accuracy. The integrated DIDSON measurement system will contribute to the protection of endangered species in rapidly changing underwater environments.
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three dimensional synthetic and real aperture sonar technologies with doppler velocity log and small fiber optic gyrocompass for autonomous underwater vehicle
OCEANS Conference, 2012Co-Authors: Akira Asada, Tamaki UraAbstract:The technologies could be expected a practical application of searching for submarine minerals, such as thermal vents a few meters high, to a depth of 3,000 meters. In order to develop exploration technologies for submarine resources, new sensor technology needs to be developed for use with autonomous underwater vehicles (AUV) or remotely operated vehicle (ROV). We have used an optic gyrocompass CDL Mini POS-II and a Doppler velocity log (DVL) RD WH300 for the research on three dimensional synthetic and real aperture sonar technologies. However, these sensors with pressure housing are too large to mount on autonomous underwater vehicle (AUV). So, in cooperation with IXBLUE and OceanWings, we created a small fiber optic gyrocompass (FOG) with motion sensors based on IMU-50 and packed it in a small pressure housing with an outer diameter 112 mm and a length 295mm. We extracted a unit composed of three-axes angular velocity and three-axes velocity sensors and a serial interface from the IMU-50, and add it to a RS-232C converter board. Then we achieved the original software for measuring heading based on the true-north, roll, and pitch angles using the raw increment data from the small fiber optic gyrocompass. Compared with the high-performance FOG IXBLUE PHINS with accuracy 0.01 degrees, the original software achieved the true north estimation with accuracy 0.25 degrees of the same one as IXBLUE Quadrance based on IMU50 without a pressure housing. As for a small DVL NavQuest 600 is employed for optical gyrocompass and DVL navigation for the SAS processing. With respect to developing and researching on three dimensional synthetic and real aperture sonar technologies, we originally designed and manufactured the five raw hydrophone arrays with 40 hydrophone elements in a shape of triangle and have made several sea tests on targets of breakwaters, fishing banks, and hydrothermal vents. So far, we have developed the software for producing three dimensional backscatter Images with the interferometry technique and autoestimation of detail navigation from overlapped echo signals of the 40 hydrophones suited for the synthetic aperture processing. The operational Acoustic frequency is 100 kHz with the result that required position accuracy for SAS processing is normally better than 2 mm. However, DVL navigation accuracy level is equal to next to 5 cm in our processing technology. So we beforehand set 5cm grids of Acoustic Images from hydrophone signals of continuous 40 pings. Next, for the purpose of achieving the required position accuracy, we estimated position errors from Acoustic Image signals within overlap area for continuous two pings. By summing the estimated errors, high accuracy positions were calculated and were used for SAS imaging. The SAS interferometry processing software is currently being improved. In addition, we designed and manufactured four raw hydrophone arrays in parallel with each other because the five raw hydrophone arrays are a little too large for the AUV. Furthermore, we add a real aperture interferometory option to the new system using a long projector.
J. Vidal - One of the best experts on this subject based on the ideXlab platform.
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How do the geological and geophysical signatures of permeable fractures in granitic basement evolve after long periods of natural circulation? Insights from the Rittershoffen geothermal wells (France)
Geothermal Energy, 2018Co-Authors: Carole Glaas, J F Girard, Albert Genter, Patricia Patrier, J. VidalAbstract:Two deep wells were drilled at Rittershoffen (Alsace, France) to produce high-temperature fluids to supply heat to a biorefinery. The GRT-2 production well was drilled to a depth of 3196 m MD and was deviated to target a permeable local fault in the granitic basement buried beneath a thick sedimentary cover. The objective of this study is to better understand the permeability of fractured reservoirs within crystalline rocks, focusing on the production well GRT-2. Based on a petrographic and mineralogical analysis of cutting samples, several granitic facies associated with hydrothermal alteration were identified on the basis of the amounts of illite, chlorite, anhydrite, secondary geodic quartz, and oxides. These observations were correlated with various geological and geophysical datasets (gamma ray, porosity, density, electrical resistivity, caliper, borehole Image logs, temperature, rate of penetration, and mud losses) to localize and identify permeable fracture zones. In sections where Acoustic Image logs were not available, such as in the deepest part of the well, the geometries of the fracture zones were interpreted from an oriented caliper log. The caliper log interpretation detected one-third of the fractures detected by Acoustic Image logs. However, two major fracture sets striking N–S and dipping eastward or westward were observed. Furthermore, a synthetic resistivity log that fits the measured resistivity log relatively well was built using the Archie and Waxman and Smits models. This approach is a proxy for estimating the porosity and the mineralogical changes based on the cation exchange capacity, which is controlled by the chlorite/illite ratio, derived from electrical logs in granitic formations. The correlation of all these results allowed the identification of a resistivity signature of a permeable fracture zone that spatially fits with the temperature signature. The major contribution of this study is the identification of a hierarchy of permeable fractures based on petrophysical signatures. The geophysical signature of fracture zones with low residual permeability exhibits a broad depth extent, whereas the geophysical signature of a highly permeable fracture zone is more localized. Past hydrothermal circulation has enlarged the altered and porous zones around open fractures, and in some cases, intense illitization has plugged these fracture zones and reduced their permeabilities.
Katsunori Mizuno - One of the best experts on this subject based on the ideXlab platform.
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automatic non destructive three dimensional Acoustic coring system for in situ detection of aquatic plant root under the water bottom
Case Studies in Nondestructive Testing and Evaluation, 2016Co-Authors: Katsunori Mizuno, Akira Asada, Xiaofei Liu, Yasufumi Fujimoto, Tetsuo Shimada, Fuyuki Katase, Makoto Murakoshi, Yasunobu Yagita, Yoshiaki WatanabeAbstract:Abstract Digging is necessary to detect plant roots under the water bottom. However, such detection is affected by the transparency of water and the working skills of divers, usually requires considerable time for high-resolution sampling, and always damages the survey site. We developed a new automatic non-destructive Acoustic measurement system that visualizes the space under the water bottom, and tested the system in the in situ detection of natural plant roots. The system mainly comprises a two-dimensional waterproof stage controlling unit and Acoustic measurement unit. The stage unit was electrically controlled through a notebook personal computer, and the space under the water bottom was scanned in a two-dimensional plane with the stage unit moving in steps of 0.01 m (±0.0001 m). We confirmed a natural plant root with diameter of 0.025–0.030 m in the reconstructed three-dimensional Acoustic Image. The plant root was at a depth of about 0.54 m and the propagation speed of the wave between the bottom surface and plant root was estimated to be 1574 m/s. This measurement system for plant root detection will be useful for the non-destructive assessment of the status of the space under the water bottom.
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application of a high resolution Acoustic video camera to fish classification an experimental study
IEEE International Underwater Technology Symposium, 2015Co-Authors: Katsunori Mizuno, Akira Asada, Xiaofei Liu, Jun Ashizawa, Yasufumi Fujimoto, Tetsuo ShimadaAbstract:In this study, we try for fish classification using high resolution Acoustic video camera at 3.0 MHz center frequency (ARIS). Newly observation method with wide in vertical and narrow in horizontal beam (WVNHB) was proposed for getting high quality Acoustic Image of swimming fish, and tested an Image processing algorithm basing on Normalized Cross Correlation (NCC) for fish classification. This high-frequency Acoustic video camera was applied to fish classification for the first time. Using the proposed observation method, we successfully obtained high quality Acoustic Images of fish and performed an Image processing algorithm on the Images.
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three dimensional mapping of aquatic plants at shallow lakes using 1 8 mhz high resolution Acoustic imaging sonar and Image processing technology
Internaltional Ultrasonics Symposium, 2014Co-Authors: Katsunori Mizuno, Akira AsadaAbstract:A new integrated measurement system that combines the Acoustic imaging sonar of DIDSON (Dual-frequency IDentification SONar) with concentrator lenses, motion sensors, and differential global positioning system (DGPS) was used to classify different species of aquatic plants and make three-dimensional (3D) mapping of them at shallow lake. In the field experiment at the Lake Yunoko, the Image was captured with a 3° concentrator lens. Difference of Gaussian (DoG) filtering was used to classify two species of aquatic plants, Chara globularis and Elodea nuttallii appeared in 2D Acoustic Images. After the classification, 3D Acoustic Image was reconstructed from the consecutive 2D processed Images. The high-resolution Acoustic Images obtained allowed us to identify individual aquatic plants with high accuracy. The integrated DIDSON measurement system will contribute to the protection of endangered species in rapidly changing underwater environments.
Albert Genter - One of the best experts on this subject based on the ideXlab platform.
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How do the geological and geophysical signatures of permeable fractures in granitic basement evolve after long periods of natural circulation? Insights from the Rittershoffen geothermal wells (France)
Geothermal Energy, 2018Co-Authors: Carole Glaas, J F Girard, Albert Genter, Patricia Patrier, J. VidalAbstract:Two deep wells were drilled at Rittershoffen (Alsace, France) to produce high-temperature fluids to supply heat to a biorefinery. The GRT-2 production well was drilled to a depth of 3196 m MD and was deviated to target a permeable local fault in the granitic basement buried beneath a thick sedimentary cover. The objective of this study is to better understand the permeability of fractured reservoirs within crystalline rocks, focusing on the production well GRT-2. Based on a petrographic and mineralogical analysis of cutting samples, several granitic facies associated with hydrothermal alteration were identified on the basis of the amounts of illite, chlorite, anhydrite, secondary geodic quartz, and oxides. These observations were correlated with various geological and geophysical datasets (gamma ray, porosity, density, electrical resistivity, caliper, borehole Image logs, temperature, rate of penetration, and mud losses) to localize and identify permeable fracture zones. In sections where Acoustic Image logs were not available, such as in the deepest part of the well, the geometries of the fracture zones were interpreted from an oriented caliper log. The caliper log interpretation detected one-third of the fractures detected by Acoustic Image logs. However, two major fracture sets striking N–S and dipping eastward or westward were observed. Furthermore, a synthetic resistivity log that fits the measured resistivity log relatively well was built using the Archie and Waxman and Smits models. This approach is a proxy for estimating the porosity and the mineralogical changes based on the cation exchange capacity, which is controlled by the chlorite/illite ratio, derived from electrical logs in granitic formations. The correlation of all these results allowed the identification of a resistivity signature of a permeable fracture zone that spatially fits with the temperature signature. The major contribution of this study is the identification of a hierarchy of permeable fractures based on petrophysical signatures. The geophysical signature of fracture zones with low residual permeability exhibits a broad depth extent, whereas the geophysical signature of a highly permeable fracture zone is more localized. Past hydrothermal circulation has enlarged the altered and porous zones around open fractures, and in some cases, intense illitization has plugged these fracture zones and reduced their permeabilities.
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permeable fracture zones in the hard rocks of the geothermal reservoir at rittershoffen france
Journal of Geophysical Research, 2017Co-Authors: Jeanne Vidal, Albert Genter, Francis ChopinAbstract:Fluid circulations in zones of fractures is a key challenge to exploit deep geothermal heat from natural reservoir. At Rittershoffen (Upper Rhine Graben, France), two geothermal boreholes, GRT-1 and GRT-2, were drilled in 2012 and 2014 respectively. They targeted the local Rittershoffen normal fault, which strikes N-S and dips westward. In this study, major natural fractures were observed in the open-holes of both wells from Acoustic Image logs correlated with other standard geophysical logs (gamma ray, neutron porosity, and caliper). Their permeability was evaluated at the borehole scale from temperature logs, mud losses and gas surveys. One originally permeable (OP) fracture zone was observed in the granite of GRT-1. In GRT-2, four OP fracture zones were observed in the granite, and two in sandstones. In GRT-2, fracture zones are composed by several fluid pathways that could explain the higher natural permeability than in GRT-1. All OP fractures are associated with positive temperature anomaly, interpreted as circulation of hot geothermal water through the permeable fracture, or negative one, interpreted as the cooling of a porous, altered and fractured zone around the permeable fracture after drilling operations. Permeability of natural fracture oriented N170° seems to be intimately linked to the secondary mineral deposits resulting from paleo-circulations. The geometrical fracture model along the wellbore suggests that the inclined trajectory of GRT-2 increases the connection between the borehole and the nearly vertical fracture network associated to the local fault. A good characterization of zones of fractures in a targeted natural reservoir allows an optimal exploitation of geothermal resource.
