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DIRECT reconstruction OF FUNCTIONAL PARAMETERS FOR DYNAMIC SPECT

IEEE TRANSACTIONS ON NUCLEAR SCIENCE 1995年第4期42卷 1249-1256页

作者： LIMBER, MA LIMBER, MN CELLER, A BARNEY, JS BORWEIN, JM VANCOUVER HOSP DIV NUCL MEDVANCOUVERBC V5Z 1M9CANADA HLTH SCI CTR VANCOUVERBC V5Z 1M9CANADA

We have developed a dynamic SPECT method which allows the prevalent rotating camera systems to be used. In this method, the parameters of the time-activity curve in each pixel are recovered directly from the projection data, without first reconstructing a series of static images. Preliminary test results show that we can accurately recover time-activity curves for a simple model based on activity values expected for myocardial viability studies with fatty acid tracers.

关键词： Cameras image reconstruction Positron emission tomography Pixel Myocardium image analysis image resolution Biochemistry Head Mathematics

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data restoration in chromo-tomographic hyperspectral imaging

Data restoration in chromo-tomographic hyperspectral imaging

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conference on image reconstruction from incomplete data

作者： An, M Brodzik, AK Mooney, J Tolimieri, R Psypher Inc Boston MA 02134 USA

ISBN: (纸本)0819437689

Recently, a new approach to hyperspectral imaging, relying on the theory of computed tomography, was proposed by researchers at the Air Force Research Laboratory. The approach allows all photons to be recorded and therefore increases robustness of the imaging system to noise and focal plane array non-uniformities. However, as all computed tomography systems, the approach suffers from the limited angle problem, which obstructs reconstruction of the hyperspectral information. In this work we present a direct, one-step algorithm for reconstruction of the unknown information based on a priori knowledge about the hyperspectral image.

关键词： hyperspectral chromotomography computed tomography singular value decomposition

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Dynamic demosaicing and color super-resolution of video sequences

Dynamic demosaicing and color super-resolution of video sequ...

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conference on image reconstruction from incomplete data III

作者： Farsiu, S Robinson, D Elad, M Milanfar, P Univ Calif Santa Cruz Dept Elect Engn Santa Cruz CA 95064 USA

ISBN: (纸本)0819455008

In the last two decades a variety of super-resolution (SR) methods have been proposed. These methods usually address the problem of fusing a set of monochromatic images to produce a single monochromatic image with higher spatial resolution. In this paper we address the dynamic and color SR problems of reconstructing a high-quality set of colored super-resolved images from low-quality mosaiced frames. Our approach includes a hybrid method for simultaneous SR and demosaicing, this way taking into account practical color measurements encountered in video sequences. For the case of translational motion and common space-invariant blur, the proposed method is based on a very fast and memory efficient approximation of the Kalman filter. Experimental results on both simulated and real data are supplied, demonstrating the presented algorithm, and its strength.

关键词： Lawrencium Optical filters image fusion Motion models Matrices image filtering Cameras Filtering (signal processing) image processing video

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FPGA acceleration by asynchronous parallelization for simultaneous image reconstruction and segmentation based on the Mumford-Shah regularization 8

FPGA acceleration by asynchronous parallelization for simult...

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conference on image reconstruction from incomplete data vIII

作者： Zhang, Wentai Luo, Guojie Shen, Li Page, Thomas Li, Peng Jiang, Ming Maass, Peter Cong, Jason Peking Univ Beijing Peoples R China PKU UCLA Joint Res Inst Sci & Engn Los Angeles CA USA NUDT Collaborat Innovat Ctr High Performance Comp Changsha Hunan Peoples R China Univ Bremen D-28359 Bremen Germany Univ Calif Los Angeles Los Angeles CA USA

ISBN: (纸本)9781628417661

X-ray computed tomography (CT) is an important technique for noninvasive clinical diagnosis and nondestructive testing. In many applications a number of image processing steps are needed before the image features are available. One of these processing steps is image segmentation, which generates the edge and the structural features of the regions of interest. The conventional flow is to first reconstruct images and then apply image segmentation methods on reconstructed images. In contrast, an emerging technique obtains the tomographic image and segmentation simultaneously, which is especially useful in the case of limited data. An iterative method for simultaneous reconstruction and segmentation (SRS) with Mumford-Shah model has been proposed, which not only regularizes the ill-posed tomographic reconstruction problem, but also produces the image segmentation at the same time. The Mumford-Shah model is both mathematically and computationally chanllenging. In this paper, we propose an asynchronous ray-parallel algorithm of the SRS method and accelerate it using field-programmable gate array (FPGA) devices, which drastically improves the energy efficiency. Experimental results show that the FPGA implementation achieves a 1.2x speedup with an energy efficiency as great as 58x, over the GPU implementation.

关键词： image reconstruction image segmentation Mumford-Shah regularization gamma-convergence asynchronous parallelization FPGA acceleration hardware pipelining

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Analytical reconstruction formula for one-dimensional Compton camera

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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 1997年第3期44卷 1342-1346页

作者： Basko, R Zeng, GL Gullberg, GT Department of Radiology University of Utah Salt Lake UT USA

The Compton camera has been proposed as an alternative to the Anger camera in SPECT. The advantage of the Compton camera is its high geometric efficiency due to electronic collimation. The Compton camera collects projections that are integrals over cone surfaces. Although some progress has been made toward image reconstruction from cone projections, at present no filtered backprojection algorithm exists. This paper investigates a simple 2D version of the imaging problem. An analytical formula is developed for 2D reconstruction from data acquired by a 1D Compton camera that consists of two linear detectors, one behind the other. Coincidence photon detection allows the localization of the 2D source distribution to two lines in the shape of a ''v'' with the vertex on the front detector. A set of ''v'' projection data can be divided into subsets whose elements can be viewed as line-integrals of the original image added with its mirrored shear transformation. If the detector has infinite extent, reconstruction of the original image is possible using data from only one such subset. Computer simulations were performed to verify the newly developed algorithm.

关键词： Cameras Detectors image reconstruction Collimators Electromagnetic scattering Particle scattering Single photon emission computed tomography Surface reconstruction Shape Computer simulation

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Determination of myosin filament positions and orientations in electron micrographs of muscle cross-sections

Determination of myosin filament positions and orientations ...

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conference on image reconstruction from incomplete data III

作者： Bödvarsson, B Klim, S Mortensen, S Morkebjerg, M Chen, J Maclaren, JR Yoon, CH Luther, PK Squire, JM Bainbridge-Smith, A Bones, PJ Millane, RP Univ Canterbury Dept Elect & Comp Engn Christchurch 1 New Zealand

ISBN: (纸本)0819455008

An automated image analysis system for determination of myosin filament orientations in electron micrographs of muscle cross-sections is described. Analysis of the distribution of the orientations is important in studies of muscle structure, particularly for interpretation of x-ray diffraction data. Filament positions are determined using h-dome extraction and image filtering, based on grayscale reconstruction. Erroneous locations are eliminated based on lattice regularity. Filament orientations are determined by correlation with a template that incorporates the salient filament characteristics and classified using a Gaussian mixture model. Application to a number of micrographs and comparison with manual classifications of orientations shows that the system is effective in many cases.

关键词： image analysis morphology electron micrograph lattice disorder myosin muscle

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Set theoretic approach to image reconstruction from projections

Set theoretic approach to image reconstruction from projecti...

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Proceedings 1996 International conference on image Processing, ICIP'96

作者： Bhumkar, Bhaskar vora, Poorvi L. Chandna, B. Shankar, K. Indian Inst of Technology - Bombay Mumbai India

The reconstruction of an image from incomplete view data requires the use of several constraints not derived from ray sum (projection data) measurements. The constraints can be incorporated through the method of (sequential and parallel) projections onto the constraint sets. These methods for the use of information regarding the noise and the image are implemented and compared in this paper. It is shown that the use of noise statistics decreases the mean square error in the image and that the method of parallel projections results in smaller error than the method of sequential projections if a sufficient number of iterations is permitted.

关键词： image reconstruction

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Weighted Total variation Constrained reconstruction for Reduction of Metal Artifact in CT

Weighted Total Variation Constrained Reconstruction for Redu...

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IEEE Nuclear Science Symposium (NSS)/Medical Imaging conference (MIC)/17th International Workshop on Room-Temperature Semiconductor X-ray and Gamma-ray Detectors

作者： Zhang, Yanbo Mou, Xuanqin Yan, Hao Xi An Jiao Tong Univ Inst Image Proc & Pattern Recognit Xian 710049 Shaanxi Peoples R China

ISBN: (纸本)9781424491063

Tv constrained reconstruction could obtain perfect results from incomplete data, and has been applied to reduce metal artifact by assuming that the projection contaminated by metal is missing. In Tv constrained reconstruction, the selection of a proper step parameter for Tv minimization procedure is a key point. However, this parameter is usually selected empirically, and it is a constant for all pixels in the whole image domain, regardless of the difference of missing projection quantity at different pixels. By analyzing the relationship between the missing projections and pixels position, a Weighted Total variation (WTv) constrained reconstruction method is proposed to reduce metal artifact in this paper. For WTv constrained method, the parameters are no longer the same, but vary over image domain as the introduced information miss rate. The simulation results show that the proposed method is more effective than current Tv constraint to reduce metal artifact. Moreover, WTv constrained method is extended to other incomplete projection problems.

关键词： Pixels

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image reconstruction by Prioritized Incremental Normalized Convolution 1

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17th Scandinavian conference on image Analysis (SCIA)

作者： Landstrom, Anders Nellros, Frida Jonsson, Hakan Thurley, Matthew Lulea Univ Technol Dept Comp Sci Elect & Space Engn S-97187 Lulea Sweden

ISBN: (数字)9783642212277

ISBN: (纸本)9783642212277

A priority-based method for pixel reconstruction and incremental hole filling in incomplete images and 3D surface data is presented. The method is primarily intended for reconstruction of occluded areas in 3D surfaces and makes use of a novel prioritizing scheme, based on a pixelwise defined confidence measure, that determines the order in which pixels are iteratively reconstructed. The actual reconstruction of individual pixels is performed by interpolation using normalized convolution. The presented approach has been applied to the problem of reconstructing 3D surface data of a rock pile as well as randomly sampled image data. It is concluded that the method is not optimal in the latter case, but the results show an improvement to ordinary normalized convolution when applied to the rock data and are in this case comparable to those obtained from normalized convolution using adaptive neighborhood sizes.

关键词： image reconstruction hole filling normalized convolution

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Geometric sensitivity of ClearPET™ Neuro

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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 2007年第1-2期571卷 235-238页

作者： Gundlich, Brigitte Weber, Simone Forschungszentrum Julich Cent Inst Elect D-52425 Julich Germany

ClearPET (TM) Neuro is a small-animal positron emission tomography (PET) scanner dedicated to brain studies on rats and primates. The design of ClearPET (TM) Neuro leads to a specific geometric sensitivity, characterized by inhomogeneous and, depending on the measurement setup, even incomplete data. With respect to reconstruction techniques, homogeneous and complete data sets are a 'must' for analytical reconstruction methods, whereas iterative methods take the geometrical sensitivity into account during the reconstruction process. Nevertheless, here a homogeneous geometric sensitivity over the field of view is highly desirable. Therefore, this contribution aims at studying the impact of different scanner geometries and measurement setups on the geometric sensitivity. A data set of coincident events is computed for certain settings that contains each possible crystal combination once. The lines of response are rebinned into normalizing sinograms and backprojected into sensitivity images. Both, normalizing sinograms and sensitivity images mirror the geometric sensitivity and therefore, provide information which setting enables most complete and homogeneous data sets. An optimal measurement setup and scanner geometry in terms of homogeneous geometric sensitivity is found by analyzing the sensitivity images. (c) 2006 Elsevier B.v. All rights reserved.

关键词： sensitivity image geometric sensitivity ClearPET (TM) Neuro

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