The Experts below are selected from a list of 13212 Experts worldwide ranked by ideXlab platform
Hansjoachim Wuensche - One of the best experts on this subject based on the ideXlab platform.
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fast multi pass 3d point segmentation based on a structured mesh graph for ground vehicles
IEEE Intelligent Vehicles Symposium, 2018Co-Authors: Patrick Burger, Hansjoachim WuenscheAbstract:Point-cloud segmentation of 3D LiDAR scans is an important preprocessing task for autonomous vehicles in on-road and especially in off-road scenarios. Clustering point measurements with the same properties into multiple homogeneous regions is a challenging task due to an uneven sampling density and lack of explicit structural information. This paper presents a novel technique to achieve a robust and fast point-cloud segmentation using the characteristic Intrinsic Sensor pattern. This pattern is characterized by the mounting position of each laser diode. A structured mesh graph is created by taking the beam calibration and the chronology of incoming data packets into account. The proposed graph-based, multi-pass point segmentation algorithm compares this pattern with a flat-world model to detect discontinuities and to set label attributes such as obstacle or free space for each vertex. Furthermore, we directly detect missing measurements and therefore generate artificial vertices considering the laser beam Intrinsics. Finally, a region-growing algorithm is applied in order to obtain cohesive objects. Experimental results show that we achieve a reliable overall performance and a good trade-off between segmentation quality and runtime of 15ms in rough terrain as well as suburban areas.
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Intelligent Vehicles Symposium - Fast Multi-Pass 3D Point Segmentation Based on a Structured Mesh Graph for Ground Vehicles
2018 IEEE Intelligent Vehicles Symposium (IV), 2018Co-Authors: Patrick Burger, Hansjoachim WuenscheAbstract:Point-cloud segmentation of 3D LiDAR scans is an important preprocessing task for autonomous vehicles in on-road and especially in off-road scenarios. Clustering point measurements with the same properties into multiple homogeneous regions is a challenging task due to an uneven sampling density and lack of explicit structural information. This paper presents a novel technique to achieve a robust and fast point-cloud segmentation using the characteristic Intrinsic Sensor pattern. This pattern is characterized by the mounting position of each laser diode. A structured mesh graph is created by taking the beam calibration and the chronology of incoming data packets into account. The proposed graph-based, multi-pass point segmentation algorithm compares this pattern with a flat-world model to detect discontinuities and to set label attributes such as obstacle or free space for each vertex. Furthermore, we directly detect missing measurements and therefore generate artificial vertices considering the laser beam Intrinsics. Finally, a region-growing algorithm is applied in order to obtain cohesive objects. Experimental results show that we achieve a reliable overall performance and a good trade-off between segmentation quality and runtime of 15ms in rough terrain as well as suburban areas.
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ITSC - Fast Dual Decomposition based Mesh-Graph Clustering for Point Clouds
2018 21st International Conference on Intelligent Transportation Systems (ITSC), 2018Co-Authors: Patrick Burger, Benjamin Naujoks, Hansjoachim WuenscheAbstract:Robust object detection is one of the key tasks for autonomous vehicles. Clustering is the fundamental step for extracting objects from 3D point clouds. We propose a fast and efficient algorithm to cluster 3D point clouds provided by modern LiDAR Sensors. The clustering is based on graph theory and local contextual information. Our method encodes weights of graph edges by adopting perceptual laws based on the Intrinsic Sensor beam pattern. This significantly increases the robustness of the segmentation process. It allows a point-wise clustering even at challenging distances and viewing angles as well as occlusions. For the sake of speed, the clustering pipeline is separated into vertical and horizontal clustering. Therefore, we split the graph into multiple vertical and horizontal line graphs which are processed in parallel. Finally, the partitioned results are merged into coherent objects using a breadth-first search algorithm. Experiments in different suburban datasets have demonstrated that our proposed method outperforms other state of the art methods, especially in complex scenes. A quantitative comparison between our method and other representative clustering methods proves the efficiency and the effectiveness of our work.
B Ruggiero - One of the best experts on this subject based on the ideXlab platform.
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NANO-SQUIDs based on niobium Dayem bridges for nanoscale applications
Journal of Physics: Conference Series, 2010Co-Authors: C Granata, A Vettoliere, E Esposito, B Ruggiero, Pravin S. Walke, Ciro Nappi, P Silvestrini, M RussoAbstract:We report on the design, the fabrication and the performance of an integrated magnetic nano-Sensor based on niobium dc-SQUID (Superconducting QUantum Interference Device) for nanoscale applications is presented. The nano-Sensors are based on nanometric niobium constrictions (Dayem bridges) inserted in a square loop having a side length of 200 nm. Measurements of voltage-flux characteristic, flux to voltage transfer factor and noise performances are reported. In small signal mode, the Sensors have shown a magnetic flux noise spectral density of 1.5 μΦ0/Hz1/2 corresponding to a spin sensitivity in unit of Bohr magneton of 60 spin/Hz1/2. Supercurrent decay measurements of these devices are also reported. Such measurements provide useful information for applications which employ the SQUID as a trigger where the Sensor works on the zero voltage state. The experimental data, have shown an Intrinsic current fluctuation less than 0.2% of the critical current at liquid helium temperature, corresponding to an Intrinsic Sensor magnetic flux resolution of a few mΦ0. In view of the nano-SQUID employments in the detection of small spin populations, the authors calculated the spin sensitivity and the magnetic response relative to the single spin, as a function of its position within the SQUID hole. The results show that the SQUID response depends strongly on the spin position.
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supercurrent decay in nano superconducting quantum interference devices for Intrinsic magnetic flux resolution
Applied Physics Letters, 2009Co-Authors: C Granata, A Vettoliere, R Russo, E Esposito, M Russo, B RuggieroAbstract:Supercurrent decay measurements of nano-superconducting quantum interference devices (SQUIDs) based on niobium constrictions (Dayem bridges) are reported. Such measurements provide useful information for applications that employ the SQUID as a trigger where the Sensor works on the zero voltage state. The nanodevice consists of a niobium thin film (30 nm thick) ring with a hole side length of 200 nm including two Dayem bridges of 120×200 nm2. The measurements of the switching current distribution from the zero voltage state and the related escape rate, as function of the bias current, have been performed by a low noise fly time technique. The experimental data have shown an Intrinsic current fluctuation less than 0.2% of the critical current at liquid helium temperature, corresponding to an Intrinsic Sensor magnetic flux resolution of a few mΦ0. The theoretical predictions based on the thermal escape process theory in the moderately damping limit are in a reasonable agreement with the experimental data.
C Granata - One of the best experts on this subject based on the ideXlab platform.
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NANO-SQUIDs based on niobium Dayem bridges for nanoscale applications
Journal of Physics: Conference Series, 2010Co-Authors: C Granata, A Vettoliere, E Esposito, B Ruggiero, Pravin S. Walke, Ciro Nappi, P Silvestrini, M RussoAbstract:We report on the design, the fabrication and the performance of an integrated magnetic nano-Sensor based on niobium dc-SQUID (Superconducting QUantum Interference Device) for nanoscale applications is presented. The nano-Sensors are based on nanometric niobium constrictions (Dayem bridges) inserted in a square loop having a side length of 200 nm. Measurements of voltage-flux characteristic, flux to voltage transfer factor and noise performances are reported. In small signal mode, the Sensors have shown a magnetic flux noise spectral density of 1.5 μΦ0/Hz1/2 corresponding to a spin sensitivity in unit of Bohr magneton of 60 spin/Hz1/2. Supercurrent decay measurements of these devices are also reported. Such measurements provide useful information for applications which employ the SQUID as a trigger where the Sensor works on the zero voltage state. The experimental data, have shown an Intrinsic current fluctuation less than 0.2% of the critical current at liquid helium temperature, corresponding to an Intrinsic Sensor magnetic flux resolution of a few mΦ0. In view of the nano-SQUID employments in the detection of small spin populations, the authors calculated the spin sensitivity and the magnetic response relative to the single spin, as a function of its position within the SQUID hole. The results show that the SQUID response depends strongly on the spin position.
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supercurrent decay in nano superconducting quantum interference devices for Intrinsic magnetic flux resolution
Applied Physics Letters, 2009Co-Authors: C Granata, A Vettoliere, R Russo, E Esposito, M Russo, B RuggieroAbstract:Supercurrent decay measurements of nano-superconducting quantum interference devices (SQUIDs) based on niobium constrictions (Dayem bridges) are reported. Such measurements provide useful information for applications that employ the SQUID as a trigger where the Sensor works on the zero voltage state. The nanodevice consists of a niobium thin film (30 nm thick) ring with a hole side length of 200 nm including two Dayem bridges of 120×200 nm2. The measurements of the switching current distribution from the zero voltage state and the related escape rate, as function of the bias current, have been performed by a low noise fly time technique. The experimental data have shown an Intrinsic current fluctuation less than 0.2% of the critical current at liquid helium temperature, corresponding to an Intrinsic Sensor magnetic flux resolution of a few mΦ0. The theoretical predictions based on the thermal escape process theory in the moderately damping limit are in a reasonable agreement with the experimental data.
Jesús Sanz - One of the best experts on this subject based on the ideXlab platform.
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Measurements of mechanical vibrations at magnetic cores of power transformers with fiber-optic interferometric Intrinsic Sensor
IEEE Journal on Selected Topics in Quantum Electronics, 2000Co-Authors: Horatio Lamela Rivera, Jose A. Garcia-souto, Jesús SanzAbstract:A fiber-optic interferometric Sensor with Intrinsic transducer\nalong a length of the fiber is presented for vibration measurements of\nthe magnetic core inside an oil-filled power transformer. The Sensor is\ndesigned for high sensitivity measurements into the harsh environment of\nelectromagnetic fields, wide temperature change, and in oil immersing.\nThis Sensor allows enough sensitivity for the application, for which\nvibrations amplitudes are due to submicron displacements at frequencies\nof 100 Hz and its harmonics, in addition, the accessibility to the\nsensing region is guaranteed by low size immune fiber-optic cables as\nwell as optical phase-based transducer/carrier of the Sensor output.\nThus, it is ideal for the requirements of the remote operation. The\ntransducer size is a few mm in length, and is compact and rugged. Our\nresults show that the vibrations of the elements constituting a power\ntransformer are directly measured, improving the indirect techniques\nactually available. Finally, the measurements inside a medium power\ntransformer at site are obtained for its application in electric plants\n
Massimo Piotto - One of the best experts on this subject based on the ideXlab platform.
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an offset compensation method with low residual drift for integrated thermal flow Sensors
IEEE Sensors Journal, 2011Co-Authors: Paolo Bruschi, Massimo PiottoAbstract:A new offset compensation approach for integrated thermal flow meters is described. The method is based on micromachined differential flow sensing structures with the heater split into two identical and symmetrical sections. The power unbalance between the two heaters is used to compensate the Intrinsic Sensor offset. The effectiveness of the approach is proven by means of experiments performed on micro flow meters fabricated by postprocessing chips produced with a commercial microelectronic process. The tests were devoted to demonstrate the robustness of the offset compensation with respect to variation of both the gas temperature and type.
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Offset compensation of integrated thermal flow Sensors by means of split heater microstructures
2009Co-Authors: Paolo Bruschi, Michele Dei, Massimo PiottoAbstract:The effectiveness of a new offset compensation technique for integrated thermal flow meters is demonstrated. A Sensor structure based on two heaters placed between two temperature probes is designed with a commercial CMOS process and fabricated by means of a post-processing technique. The power unbalance between the two heaters is used to compensate the Intrinsic Sensor offset. Experiments, performed in nitrogen at different temperatures, confirm the reduction of both offset and its temperature drift by nearly one order of magnitude.
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Postprocessing, readout and packaging methods for integrated gas flow Sensors
Microelectronics Journal, 2009Co-Authors: Paolo Bruschi, Massimo Piotto, N. BacciAbstract:Two different architectures of integrated thermal flow meters based on a differential temperature configuration are investigated. A standard structure made up of a heater placed between two temperature probes has been compared to a recently proposed variant equipped with a double heater. The latter has shown a different dependence of the response on gas type when driven in a closed loop fashion. The possibility of using this architecture to compensate the Intrinsic Sensor offset has also been proposed. Devices have been fabricated by means of a simple and low cost postprocessing technique applied to chips fabricated with two distinct commercial processes. Postprocessing variants, imposed by the sophistication of modern processes, have been proposed and discussed. A compact gas flow Sensor with the readout electronics integrated on the same chip has been fabricated and characterized. Experimental results on this device and new data on double heater structures have been discussed and compared with the reviewed data of previously presented devices.
