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15th International Meeting on Fully Three-Dimensional Image reconstruction in Radiology and Nuclear Medicine

作者： Xu, Jingyan Noo, Frederic Johns Hopkins Univ Baltimore MD 21218 USA Univ Utah Salt Lake City UT USA

ISBN: (数字)9781510628380

ISBN: (纸本)9781510628380

Many model based image reconstruction (MBIR) methods for x-ray CT are formulated as convex minimization problems. If the objective function is nonsmooth. primal-dual algorithms are applicable with the drawback that there is an increased memory cost due to the dual variables. Some algorithms recently developed for large-scale nonsmooth convex programs use adaptive smoothing techniques and are of the primal type. That is, they achieve convergence without introducing the dual variables, hence without the increased memory. We discuss one such algorithm with an O(1/k) convergence rate, where k is the iteration number. We then present an extension of it to handle strong convex objective functions. This new algorithm has the optimal convergence rate of O(1/k(2)) for its problem class. Our preliminary numerical studies demonstrate competitive performance with respect to an alternative method.

关键词： reconstruction algorithms algorithm development Image restoration Computer programming Control systems CT reconstruction Performance modeling computer programming reconstruction algorithm image restoration technique control systems computer programs PERFORMANCE MODELING smoothing Objective function X-Ray Computed Tomography Converge Convexity algorithms

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Interferometric SAR Processing:From TerraSAR-X to TanDEM-X

Interferometric SAR Processing:From TerraSAR-X to TanDEM-X

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European conference on synthetic aperture radar

作者： Thomas Fritz Helko Breit N. Adam M. Eineder M. Lachaise German Aerospace Center (DLR) Remote Sensing Technology Institute D-82234 Wessling Germany

ISBN: (纸本)9783800730841

In 2009, the German radar satellite TerraSAR-X will be supplemented with its twin;the TanDEM-X satellite. Together, they will fulfil the primary TanDEM-X mission goal of deriving a global Digital Elevation Model (DEM) with an unprecedented accuracy corresponding to HRTI-3 specifications (2 m relative point-to-point height accuracy for moderate terrain at 12 m posting). First interferometric processing results from TerraSAR-X repeat-pass acquisitions impressively demonstrate the DEM accuracy that can be achieved from such high resolution X band data. They also confirm the suitability of the phase preserving focussing algorithms, the successful migration of the InSAR algorithms from SRTM to the new challenging TerraSAR-X domain (requiring e.g. terrain dependent co-registration) and the stability of the instrument. This paper outlines the planned SAR data workflow from screening over bistatic focussing and interferometric processing to raw DEM generation. It addresses some aspects of the SAR processing algorithm which exploits the synergies of bistatic focussing and interferometric processing parameter calculation. Intermediate complex image products are introduced. Emphasis is laid on required co-registration accuracy and multi-baseline phase unwrapping and DEM reconstruction algorithms foreseen for the TanDEM-X data processing.

关键词： Synthetic aperture radar terrains processing algorithm reconstruction algorithm

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Electrical impedance tomography using adaptive mesh refinement

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Journal of Shanghai University(English Edition) 2006年第3期10卷 228-232页

作者：严佩敏王朔中 School of Communication and In formation Engineering Shanghai University Shanghai 200072 P . R . China

In electrical impedance tomography （EIT）, distribution of the internal resistivity or conductivity of an unknown object is esti- mated using measured boundary voltage data induced by different current patterns with various reconstruction algorithms. The reconstruction algorithms usually employ the Newton-Raphson iteration scheme to visualize the resistivity distribution inside the object. Accuracy of the imaging process depends not only on the algorithm used, but also on the scheme of finite element discretization. In this paper an adaptive mesh refinement is used in a modified reconstruction algorithm for the regularized Err. The method has a major impact on efficient solution of the forward problem as well as on achieving improved image resolution. Computer simulations indicate that the Newton-Raphson reconstruction algorithm for Err using adaptive mesh refinement performs better than the classical Newton-Raphson algorithm in terms of reconstructed image resolution.

关键词： electrical impedance tomography mesh refinement reconstruction algorithm exponentially weighted least square criterion..

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Regularization Parameter Selection for Electrical Impedance Tomography Measurement

Regularization Parameter Selection for Electrical Impedance ...

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2009 9th International Conference on Electronic Measurement & Instruments（ICEMI’2009）

作者： Wenqin Wang1 2 Jingye Cai1 Lian Yang1 1 School of Communication and Information Engineering University of Electronic Science and Technology of China Chengdu 610054 China (2 Henan Key Laboratory of Coal Mine Methane and Fire Prevention Henan University Henan China)

Electrical impedance tomography （EIT） belongs to a family of electromagnetic imaging modalities, which is a technique used to create image of the electrical properties in the interior of a medium from measurements on its boundary. In principle, measuring both the amplitude and the phase angle of the voltage or current can result in image of the electrical conductivity and permittivity distributions in the interior of the volume. However, the impedance distribution reconstruction in EIT is a nonlinear inverse problem, in which a small amount of noise in the data can lead to enormous errors in the estimates. This ill-posedness problem can be processed with regularization methods. The regularization parameter should be carefully chosen, but it is often heuristically selected in the conventional regularization-based reconstruction algorithms. In this paper, regularization parameter selection for EIT is investigated. Numerical analysis and simulation results are performed to illustrate EIT image reconstruction using different regularization parameters. It is shown that choosing the appropriate regularization parameter plays an important role in EIT image reconstruction.

关键词： Electrical impedance tomography (EIT) reconstruction algorithm regularization parameter inverse problem Tikhonov.

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Through-The-Wall Tomographic Imaging Using Chirp Signals

Through-The-Wall Tomographic Imaging Using Chirp Signals

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2011 IEEE International Symposium on Antennas and Propagation(APSURSI 2011)

作者： Ling Huang Yilong Lu School of Electrical and Electronic Engineering Nanyang Technological University Singapore

ISBN: (纸本)9781424495627;9781424495634

This paper presents a feasibility study of using chirp signal for through-the-wall radar imaging and indoor positioning applications. Chirp signal enables frequency diversity while multistatic geometry of tomographic imaging enables space diversity. Pulse compression of chirp aims for range compression of received signals. Beamforming reconstruction algorithm is then applied on compressed signals to produce the final image. In the computer simulation experiments, we have considered using chirp signal and pulsed sine signal as transmitting signals for point targets imaging with building walls in different situations. This study draws a conclusion that using chirp signals, high-quality imaging and positioning results can be obtained.

关键词： tomographic imaging chirp signal through-the-wall imaging CHIRP SIGNALS Chirp modulation Tomography sinusoidal signal compressed signal simulation test Buildings-Walls Frequency diversity received signal reconstruction algorithm

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Tomographic method for measurement of the refractive index profile of optical fibre preforms and rod GRIN lenses

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JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 2002年第7B期41卷 4821-4824页

作者： Acosta, E Flores, R Vázquez, D Ríos, S Garner, L Smith, G Univ Santiago de Compostela Dept Fis Aplicada Santiago De Compostela Spain Univ La Laguna Dept Fis Basica E-38207 San Cristobal la Laguna Spain Univ Auckland Dept Optometry & Vis Sci Auckland 1 New Zealand Univ Melbourne Dept Optometry & Vis Sci Parkville Vic 3052 Australia

We present a new iterative tomographic method to reconstruct refractive index profiles of cross sections of fibre preforms or gradient index cylindrical lenses. Numerical simulation shows that the technique allows accuracy up to the fourth decimal place provided that the refractive index can be regarded as an analytical function of the radial coordinate. The method is conceptually simple, it does not require accurate matching of the index of the surrounding medium to that of the surface of the lens and the related iterative process rapidly converges.

关键词： tomography gradient index lenses refractive index reconstruction algorithm

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Power Quality Data Compression Based on Sparse Representation and Compressed Sensing 11

Power Quality Data Compression Based on Sparse Representatio...

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11th World Congress on Intelligent Control and Automation

作者： Shen, Yue Zhang, Hanwen Liu, Guohai Liu, Hui Xia, Wei Wu, Hongxuan Jiangsu Univ Sch Elect & Informat Engn Zhenjiang Jiangsu Peoples R China

ISBN: (纸本)9781479958252

A power quality data compression method combining compressive sampling with adaptive matching pursuit reconstruction based on compressed sampling theorem is presented to solve the massive power quality data collection, compression and storage problems. First, the original power quality data was sampled and compressed simultaneously by random matrix projection method based on compressed sampling theorem. Then the proposed adaptive matching pursuit reconstruction algorithm was used to achieve accurate power quality data reconstruction. The proposed method breaks through the traditional framework of data compression by merging compression into sampling process and could reconstruct original power quality data from the small amount of sampling points from the compressed data. Simulation shows the proposed CS-based power quality data compression method can not only reduce hardware requirements, but also increase the efficiency of data compression.

关键词： power quality data compression compressed sensing reconstruction algorithm

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Exemplar-based Image Inpainting via Fast Global Optimal Searching

Exemplar-based Image Inpainting via Fast Global Optimal Sear...

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2017 IEEE 第2届先进信息技术,电子与自动化控制国际会议(IAEAC 2017)

作者： Bing Yu Youdong Ding Shanghai Film Academy of Shanghai University

This paper presents an image inpainting algorithm which relies on the fast global optimal searching. The whole framework of our method is focused on approximating the minimum of the proposed energy fu

ISBN: (纸本)9781467389808

关键词： Exemplar-based inpainting Global image inpainting PatchMatch Poisson editing Nearest neighbor global optimum Image images Imagery (Psychotherapy) texture Lighting illumination Searches Fasting reconstruction algorithm textures iterative calculation

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Learning to Find Occlusion Regions

Learning to Find Occlusion Regions

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IEEE Conference on Computer Vision and Pattern Recognition

作者： Ahmad Humayun Oisin Mac Aodha Gabriel J. Brostow University College London

ISBN: (纸本)9781457703942

For two consecutive frames in a video, we identify which pixels in the first frame become occluded in the second. Such general-purpose detection of occlusion regions is difficult and important because one-to-one correspondence of imaged scene points is needed for many tracking, video segmentation, and reconstruction algorithms. Our hypothesis is that an effective trained occlusion detector can be generated on the basis of i) a broad spectrum of visual features, and ii) representative but synthetic training sequences. By using a Random Forest based framework for feature selection and training, we found that the proposed feature set was sufficient to frequently assign a high probability of occlusion to just the pixels that were indeed becoming occluded. Our extensive experiments on many sequences support this finding, and while accuracy is certainly still scene-dependent, the proposed classifier could be a useful preprocessing step to exploit temporal information in video.

关键词： Occlusion Videotapes pixel time information One-to-one correspondence reconstruction algorithm Feature extraction occluding Frame FINDINGS training sequence

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A Theory of Plenoptic Multiplexing

A Theory of Plenoptic Multiplexing

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IEEE Conference on Computer Vision and Pattern Recognition

作者： Ivo Ihrke Gordon Wetzstein Wolfgang Heidrich The University of British Columbia

ISBN: (纸本)9781424469840;9781424469857

Multiplexing is a common technique for encoding high-dimensional image data into a single, two-dimensional image. Examples of spatial multiplexing include Bayer patterns to capture color channels, and integral images to encode light fields. In the Fourier domain, optical heterodyning has been used to acquire light fields. In this paper, we develop a general theory of multiplexing the dimensions of the plenoptic function onto an image sensor. Our theory enables a principled comparison of plenoptic multiplexing schemes, including noise analysis, as well as the development of a generic reconstruction algorithm. The framework also aides in the identification and optimization of novel multiplexed imaging applications.

关键词： MULTIPLEXOR Light fields Sensors (image) noise analysis space division multiplexing reconstruction algorithm image data color channel Optical heterodyning

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