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IEEE Radar Conference

作者： Can Evren Yarman Ling Wang Birsen Yazici Houston Technology Center WesternGeco Schlumberger College of Information Science and Technology Nanjing University of Aeronautics and Astronautics Department of Electrical Computer and System Engineering Rensselaer Polytechnic Institute

ISBN: (纸本)9781424458110

In this paper we consider passive airborne receivers that use backscattered signals from sources of opportunity transmitting fixed-frequency waveforms. Due to its combined passive synthetic aperture and the fixed-frequency nature of the transmitted waveforms, we refer to the system under consideration as Doppler Synthetic Aperture Hitchhiker (DSAH). We present a novel image formation method for DSAH. Our method first correlates the windowed signal obtained from one receiver with the windowed, filtered, scaled and translated version of the received signal from another receiver. This processing removes the transmitter related variables from the phase of the Fourier integral operator that maps the radiance of the scene to the correlated signal. We next use the microlocal analysis to reconstruct the scene radiance by the weighted-backprojection of the correlated signal. This imaging algorithm can put the visible edges of the scene radiance at the correct location, and under appropriate conditions, with correct strength. Additionally, it is an analytic reconstruction technique which can be made computationally efficient. We show that the resolution of the image is directly related to the length of the support of the windowing function and the frequency of the transmitted waveform. The image reconstruction method is applicable with both cooperative and non-cooperative sources of opportunity using one or more airborne receivers. We present numerical simulations to demonstrate the performance of the image reconstruction method and to verify the theoretical results.

关键词： Synthetic aperture image reconstruction radiance single-frequency received signal fixed frequency image resolution Radar polarimetry reconstruction algorithm signals waveforms

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Development on Electrical Capacitance Tomography System

Development on Electrical Capacitance Tomography System

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ICEMI'2005第七届国际电子测量与仪器学术会议

作者： Zhao Jinchuang Fu Wenli (Guangxi University, Nanning 530004 China)

An Electrical capacitance tomography (ECT) system includes its sensor, measuring circuit and image reconstruction algorithm is described in this paper. An AC-based capacitance circuit is introduced be

关键词： Electrical capacitance tomography measuring circuit reconstruction algorithm two-phase flow.

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Transmission and Scattering Experiments Using YAP(Ce) and CsI(Tl)

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Journal of Nuclear Science and Technology 2004年 41卷 350-353页

作者： Park, Sung Ho Park, Ji Sung Kim, Jong Kyung Hanyang University Seoul 133-791 17 Haengdang-dong Seongdong-gu South Korea

In order to develop a new concept of baggage inspection system, an experimental system consisting of a gamma source, detector sets, spectrometry, and counting system is prepared. The X-ray scattered signals from a scanned object can contain the information on the atomic composition of the materials constituting the object while the conventional baggage inspection system uses transmission signals related to mass or electron density. 10 mCi Co-57 is used as a radiation source for scanning the test material in this work. Simple transmission and scattering experiments are performed for various test materials, and the measured results are compared with the calculated values. The experiment results from this work will be used in the verification of reconstruction algorithm which requires transmission and scattering signals at the same time to identify the unknown materials. © 2014 Atomic Energy Society of Japan.

关键词： Compton Scattering Inspection System reconstruction algorithm

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采用非均匀细分网格提高电阻抗成象图象精度的方法

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上海大学学报(英文版) 2001年第S1期4卷 42-46页

作者：张伟民莫玉龙 School of Communication and Information Engineering Shanghai University

In electrical impedance tomography (EIT) an approximation for the internal resistivity distribution is computed based on the knowledge of the injected currents and measured voltages on the surface of the body. Several difficulties have been identified in EIT, where the main problem is the low spatial resolution. This paper presents a fining mesh method based on finite element method (FEM), by fining the sensitive element, the most actual signal is obtained in certain electrode number. Newton-Raphson reconstruction algorithm improves the spatial solution of image. The advantages of this method are the improvement of spatial resolution and ease of implementation.

关键词：非均匀细分网格电阻抗成象图象精度方法 Electrical Impedance spatial resolution reconstruction algorithm finite element method electrical impedance

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Three dimension imaging method based on cone beam-RT scanning mode

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Guangxue Jishu/Optical Technique 2006年第4期32卷 567-570页

作者： Gong, Lei Fu, Jian Lu, Hong-Nian Zhao, Fei Beijing University of Aeronautics and Astronautics Beijing 100083 China

Since FDK reconstruction algorithm with circular orbit scan mode based on cone beam can only be used when the cone angle is small, the field of view is too narrow to scan large objects, a new reconstruction algorithm of 3D-ICT based on cone beam-RT(rotation and transverse) scanning-mode is developed. In the first step, X-ray projection data were gathered by 2-D flat panel detector for three times in the horizontal direction, accompanied with the rotation motion in every horizontal locations. Furthermore, the projection data are rebound to oblique parallel projection data. Then the data are backprojected into the 3D-reconstruction image after the data have been preweighted and filled. Simulation experiment results show that the algorithm can acquire the satisfactory image quality with wider field of view in order to scan large objects. Analysis results show that the scanning field of view along the horizon can be improved to 2.88 times compared with classic FDK algorithm.

关键词： 3D-ICT Circular orbit scan Industrial CT Large field of view scan reconstruction algorithm

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Self-Localization and 3-D Model Construction of Pipe by Earthworm Robot Equipped with Omni-Directional Rangefinder

Self-Localization and 3-D Model Construction of Pipe by Eart...

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IEEE International Conference on Robotics and Biomimetics

作者： Atsushi Yamashita Kenki Matsui Ryosuke Kawanishi Toru Kaneko Taro Murakami Hayato Omori Taro Nakamura Hajime Asama Department of Precision Engineering The University of Tokyo Department of Mechanical Engineering Faculty of Engineering Shizuoka University Department of Precision Mechanics Chuo University

ISBN: (纸本)9781457721366

A lot of plumbings such as gas pipes and water pipes exist in public utilities, factories and so on. The use of an omni-directional camera which can take images of 360 deg in surroundings at a time is effective for pipe inspection. However, shape measurement is difficult only with the omni-directional camera. Therefore, in this paper, we propose a reconstruction method of a piping shape by using a rangefinder constructed with an omni-directional camera and an omni-directional laser. The rangefinder is mounted on an earthworm robot. Our method calculates 3-D coordinates by the light section method. By integrating the 3-D coordinates with the information of camera motion estimated by the structure from motion technique, the shape of the pipe is reconstructed. The validity of the proposed method is shown through experiments.

关键词： Rangefinders Pipe profiled pipe gas pipeline Cameras light sections Water pipe reconstruction algorithm earthworms Three Dimensions Robot

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Fast Katsevich algorithm based on GPU for helical cone-beam computed tomography

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IEEE transactions on information technology in biomedicine : a publication of the IEEE Engineering in Medicine and Biology Society 2010年第4期14卷 1053-61页

作者： Guorui Yan Jie Tian Shouping Zhu Chenghu Qin Yakang Dai Fei Yang Di Dong Ping Wu Medical Image Processing Group Institute of Automation Chinese Academy of Sciences Beijing 100190 China. yangr@***

Katsevich reconstruction algorithm represents a breakthrough for helical cone-beam computed tomography (CT) reconstruction, because it is the first exact cone-beam reconstruction algorithm of filtered backprojection (FBP) type with 1-D shift-invariant filtering. Although FBP-type reconstruction algorithm is effective, 3-D CT reconstruction is time-consuming, and the accelerations of Katsevich algorithm on CPU or cluster have been widely studied. In this paper, Katsevich algorithm is accelerated by using graphics processing unit, including flat-detector and curved-detector geometry in the case of helical orbit. An overscan formula is derived, which helps to avoid unnecessary overscan in practical CT scanning. Based on the overscan formula, a volume-blocking method in device memory is proposed. One advantage of the blocking method is that it can reconstruct large volume with high speed.

关键词： Computed tomography (CT) Katsevich algorithm graphics processing unit (GPU) overscan Memory devices Tomography Helical GRAPPER PICK UP Graphics Processing Unit reconstruction algorithm X-Ray Computed Tomography acceleration large volume Helical orbit central processing units High speed Cone-Beam Computed Tomography

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Low frequency ultrasonic pulse-echo datasets for object detection and thickness measurement in concrete specimens as testing tasks in civil engineering

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DATA IN BRIEF 2023年 48卷 109233页

作者： Maack, Stefan Kuettenbaum, Stefan Buehling, Benjamin Borchardt-Giers, Kerstin Assmann, Norman Niederleithinger, Ernst Bundesanstalt Mat Forsch & Prufung BAM Unter Eichen 87 D-12205 Berlin Germany

The dataset contains raw data gathered with the ultrasonic pulse-echo method on concrete specimens. The surfaces of the measuring objects were automatically scanned point by point. Pulse-echo measurements were performed at each of these measuring points. The test specimens represent two typical testing tasks in construction industry: the detection of objects and the determination of dimensions to describe the geometry of components. By automating the measurement process, the different test scenarios are examined with a high repeatability, precision and measuring point density. Longitudinal and transversal waves were used and the geometrical aperture of the testing system was varied. The low-frequency probes operate in a range of up to approximately 150 kHz. In addition to the specification of the geometrical dimensions of the individual probes, the directivity pattern and the sound field characteristics are provided. The raw data are stored in a universally readable format. The length of each time signal (A-scan) is two milliseconds and the sampling rate is two mega-samples per second. The provided data can be used for comparative studies in signal analysis, imaging and interpretation as well as for evaluation purposes in different, practically relevant testing scenarios. (c) 2023 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://***/licenses/by/4.0/)

关键词： Pulse-echo method Non-destructive testing reconstruction algorithm SAFT Evaluation Validation Piezoelectric transducer Civil engineering

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Low frequency ultrasonic dataset for pulse echo object detection in an isotropic homogeneous medium as reference for heterogeneous materials in civil engineering

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DATA IN BRIEF 2022年 42卷 108235页

作者： Maack, Stefan Kuettenbaum, Stefan Buehling, Benjamin Niederleithinger, Ernst Bundesanstalt Mat Forsch & Prufung BAM Unter Eichen 87 D-12205 Berlin Germany

The dataset presented contains ultrasonic data recorded in pulse echo mode. The investigated specimen is made of the isotropic homogeneous material polyamide and has a drill hole of constant diameter running parallel to the surface, which was scanned in a point grid using an automatic scanner system. At each measuring position, a pitch-catch measurement was performed using a sampling rate of 2 MHz. The probes used are arrays consisting of a spatially separated receiving and in-phase transmitting unit. The transmitting and receiving sides each consist of 12 point-shaped single probes. These dry-point contact (DPC) probes operate according to the piezoelectric principle at nominal frequencies of 55 kHz (shear waves) and 100 kHz (longitudinal waves), respectively, and do not require a coupling medium. The measurements are performed with longitudinal (100 kHz) and transverse (55 kHz) waves with different geometric orientations of the probe on the measurement surface. The data presented in the article provide a valid source for evaluating reconstruction algorithms for imaging in the low-frequency ultrasound range. (C) 2022 The Authors. Published by Elsevier Inc.

关键词： Ultrasound Pulse-echo method Non-destructive testing reconstruction algorithm Reference material Validation Piezoelectric transducer Civil engineering

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