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International conference on Physics and Control

作者： I.v. Denisov E.v. Denisova N.A. Rybalchenko v.A. Sedov Control Processes of Far Eastern Branch of RAS Institute of Automation Vladivostok Russia Far Eastern State University Vladivostok Russia Maritime State University Vladivostok Russia

In this article the principles of fiber-optical tomography are described. The definition of the fiber-optical tomography problem is made. The approximate algebraic and neural-like methods of the solution of the tomography problem of reconstruction of the physical fields characteristics are considered. The analyses of applicability of these methods for fiber-optical reconstructive tomography are made. The problem of simultaneous reconstruction of the places and values of influences on fiber-optical measuring network from 4/spl times/4 dimension is described. As the tomography data the integrated data coming from the fiber-optical measuring lines stacked on two and three directions on fiber-optical measuring network of researched area were used.

关键词： Tomography Optical fiber devices Optical fibers Area measurement Electromagnetic measurements Optical sensors Distribution functions image reconstruction Bandwidth Electromagnetic interference

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video epitomes

Video epitomes

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conference on Computer vision and Pattern Recognition (CvPR)

作者： v. Cheung B.J. Frey N. Jojic Electrical and Computer Engineering University of Toronto Toronto ONT Canada Machine Learning and Applied Statistics Microsoft Research Limited Redmond WA USA

Recently, "epitomes" were introduced as patch-based probability models that are learned by compiling together a large number of examples of patches from input images. In this paper, we describe how epitomes can be used to model video data and we describe significant computational speedups that can be incorporated into the epitome inference and learning algorithm. In the case of videos, epitomes are estimated so as to model most of the small space-time cubes from the input data. Then, the epitome can be used for various modeling and reconstruction tasks, of which we show results for video super-resolution, video interpolation, and object removal. Besides computational efficiency, an interesting advantage of the epitome as a representation is that it can be reliably estimated even from videos with large amounts of missing data. We illustrate this ability on the task of reconstructing the dropped frames in video broadcast using only the degraded video.

关键词： Statistics video compression Probability image reconstruction Optical computing data analysis Libraries Spatial resolution image resolution Biological system modeling

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Full body tracking from multiple views using stochastic sampling

Full body tracking from multiple views using stochastic samp...

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conference on Computer vision and Pattern Recognition (CvPR)

作者： R. Kehl M. Bray L. van Gool Computer Vision Laboratory (BIWI) ETH Zurich Switzerland Department of Computing Oxford Brookes University Oxford UK ESAT-PSI University of Leuven Belgium

We present a novel approach for full body pose tracking using stochastic sampling. A volumetric reconstruction of a person is extracted from silhouettes in multiple video images. Then, an articulated body model is fitted to the data with stochastic meta descent (SMD) optimization. By comparing even a simplified version of SMD to the commonly used Levenberg-Marquardt method, we demonstrate the power of stochastic compared to deterministic sampling, especially in cases of noisy and incomplete data. Moreover, color information is added to improve the speed and robustness of the tracking. Results are shown for several challenging sequences, with tracking of 24 degrees of freedom in less than 1 second per frame.

关键词： Stochastic processes Sampling methods Robustness Hardware Cameras Computer vision image sampling Humans Application software Target tracking

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A corpus for comparative evaluation of OCR software and postcorrection techniques

A corpus for comparative evaluation of OCR software and post...

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International conference on Document Analysis and Recognition

作者： S. Mihov K.U. Schulz C. Ringlstetter v. Dojchinova v. Nakova K. Kalpakchieva O. Gerasimov A. Gotscharek C. Gercke IPP-Bulgarian Academy of Sciences Sofia Bulgaria CIS University of Munich Germany CIS University of Munich (LMU) Germany

We describe a new corpus collected for comparative evaluation of OCR-software and postcorrection techniques. The corpus is freely available for academic groups and use. The major part of the corpus (2306 files) consists of Bulgarian documents. Many of these documents come with Cyrillic and Latin symbols. A smaller corpus with German documents has been added. All original documents represent real-life paper documents collected from enterprises and organizations. Most genres of written language and various document types are covered. The corpus contains the corresponding image files, rich meta-data textual files obtained via OCR recognition, ground truth data for hundreds of example pages, and alignment software for experiments.

关键词： Optical character recognition software Natural languages image recognition Testing Text analysis Computational Intelligence Society Character recognition Application software image reconstruction

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Dynamic imaging on the high resolution research tomograph (HRRT): non-human primate studies

Dynamic imaging on the high resolution research tomograph (H...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： v. Sossi M.-L. Camborde S. Blinder A. Rahmim K.J.-C. Cheng K.R. Buckley D.J. Doudet T.J. Ruth University of British Columbia Vancouver BC Canada TRIUMF Vancouver BC Canada Department of Radiology Johns Hopkins University School of Medicine Baltimore MD USA

The high resolution research tomography (HRRT) is currently the most complex human brain scanner due to its ability to detect the gamma depth of interaction, its octagonal geometry, and the large number of crystals (119,808) leading to approximately 4.5 /spl times/ 10/sup 9/ possible lines of response (LORs). reconstruction of dynamic studies on this scanner is particularly challenging due to the dynamic range of both, number of acquired events per frame and acquisition count rates. Some artifacts have been observed with phantom studies: here we evaluate their impact on time activity curves (TACs) and binding potential (BP) values in realistic scanning situations with the ultimate goal of defining an efficient and accurate image reconstruction protocol. Non-human primate studies were used for this purpose. We compared TACs and BPs obtained from images reconstructed with three different reconstruction algorithms, two different axial spanning configurations and detector normalization factors obtained from two different data sets. We also compared BP values obtained from scans of the same animal performed on the Siemens ECAT 963B and the HRRT under identical conditions. The statistical reconstruction methods produced nearly identical results and the impact of emission/normalization count rate mismatch was found to be effectively negligible. Likewise no image degradation due to increased axial spanning was observed. data obtained from the analytical method were less robust and in general much more sensitive to noise, thus demonstrating a suboptimal performance of this algorithm. The BP values obtained with the HRRT were by approximately 50% higher compared to those obtained in the ECAT as a result of the increased resolution of this tomograph.

关键词： High-resolution imaging image resolution image reconstruction reconstruction algorithms Optical imaging Tomography Humans Gamma ray detection Gamma ray detectors Geometry

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Face recognition based on frontal views generated from non-frontal images

Face recognition based on frontal views generated from non-f...

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conference on Computer vision and Pattern Recognition (CvPR)

作者： v. Blanz P. Grother P.J. Phillips T. vetter Max Planck Institut für Informatik Saarbrucken Germany National Institute for Standards and Technology Gaithersburg MD USA Department Informatik University of Basel Basel Switzerland

This paper presents a method for face recognition across large changes in viewpoint. Our method is based on a morphable model of 3D faces that represents face-specific information extracted from a dataset of 3D scans. For non-frontal face recognition in 2D still images, the morphable model can be incorporated in two different approaches: in the first, it serves as a preprocessing step by estimating the 3D shape of novel faces from the non-frontal input images, and generating frontal views of the reconstructed faces at a standard illumination using 3D computer graphics. The transformed images are then fed into state-of-the-art face recognition systems that are optimized for frontal views. This method was shown to be extremely effective in the Face Recognition vendor Test FRvT 2002. In the process of estimating the 3D shape of a face from an image, a set of model coefficients are estimated. In the second method, face recognition is performed directly from these coefficients. In this paper we explain the algorithm used to preprocess the images in FRvT 2002, present additional FRvT 2002 results, and compare these results to recognition from the model coefficients.

关键词： Face recognition image generation Shape data mining data preprocessing image reconstruction Lighting Computer graphics Testing image recognition

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A noise equivalent counts approach for optimizing I-124 imaging performance with a small animal PET scanner

A noise equivalent counts approach for optimizing I-124 imag...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Qinan Bao v. Kohli F.R. Rannou A.F. Chatziioannou Crump Institute for Molecular Imaging David Geffen School of Medicine UCLA Los Angeles CA USA PET Department The Queen's Medical Center Honolulu HI USA Departmento de Ingenieria Informatica Universidad de Santiago de Chile

Due to its long radiological half life, 124 I can be used for investigation of lengthy biological processes. However, it is not an ideal PET isotope because it has poor positron yield and half of the positrons are emitted in cascade with 603 kev gammas. This decay spectrum results in coincidences between gammas and annihilation photons (dirty coincidences) leading to both inaccurate quantitation and overall reduction in the image quality. It has been shown that noise equivalent counts (NEC) have a direct link to signal to noise ratio of the reconstructed images. The purpose of this work was to investigate the effect of varying the energy window of the digitizer on the NEC measured from the non-pure positron emitter 124 I and hence, on the image quality. Simulations were performed using the GATE software for a 1.32 cm radius cylinder filled with 300 muCi of 124 I placed at the center of field of view. We report that by windowing in on the upper energy window of the data acquisition from a symmetric 50% (255-766 kev) energy window, to an asymmetric 255-600 kev one, it is possible to preferentially reduce the dirty coincidences with minor sensitivity changes. These findings will be verified with experimental data, and will lead to optimizing the data acquisition chain for 124 I imaging performance

关键词： Animals Positron emission tomography image quality Signal to noise ratio National electric code data acquisition Biological processes Isotopes image reconstruction Energy measurement

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Fusing signatures of different physical processes in muon tomography

Fusing signatures of different physical processes in muon to...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： A.v. Klimenko C.L. Morris W.C. Priedhorsky K.N. Borozdin L.J. Schultz

We explored the cosmic ray flux attenuation, the induction of electro-magnetic showers, and muonic X-rays as a means to radiograph small scale objects. We are reporting on the value of the signatures provided by these physical processes to the muon tomography. The results of the related experiments and the Monte-Carlo calculations that we performed are discussed. Based on our data and our validated models we present the type of information that can be drawn from signatures of the above processes, the value, and the associated cost of this information. We discuss the general requirements to the detector systems that have to be met in order to reach the desired signal to noise ratio and make use of cosmic ray flux attenuation, induction of electromagnetic showers, and muonic X-rays in muon tomography

关键词： Mesons Tomography Electrons Attenuation Cosmic rays X-rays Radiography image reconstruction Earth Energy loss

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Using bootstrap identifiability as a metric for model selection for dynamic [/sup 11/C]DASB PET data

Using bootstrap identifiability as a metric for model select...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： R.T. Ogden A. Ojha K. Erlandsson R. van Heertum J.J. Mann R.v. Parsey Department of Psychiatry Columbia University New York NY USA Department of Radiology Columbia University New York NY USA

Numerous tracer kinetic models have been developed for estimation of neuroreceptor binding parameters from dynamic PET and SPECT brain studies. We have used the bootstrap technique to determine the variability of the parameter estimation as an aid in selecting the most appropriate kinetic model to use. This technique made it possible to take into account different sources of variability. We applied the method to data from 11 healthy subjects, each one scanned twice with the PET serotonin transporter ligand [ 11 C]DASB. Tracer binding was quantified for different brain regions by kinetic analysis, based on metabolite corrected arterial plasma input functions. Six different analysis methods were used, including iterative as well as non-iterative implementations of 1- and 2-tissue compartmental models (1TC, 2TC, 1TCNI, 2TCNI), likelihood estimation in graphical analysis (LEGA), and basis pursuit (Basis). We applied the bootstrap technique to the PET data, as well as to the plasma and metabolite data. Standard errors (SE) were calculated for the total volume distribution (v T ), as well as different binding potential estimates. The average and standard deviation (SD) of the estimated SE values were calculated across subjects. For comparison, we also estimated the variability of the outcome measures by bootstrapping only the tissue data. The results of the full bootstrap analysis showed that Basis was in general the best method. However, when only the tissue data were bootstrapped, the results indicated that 1TCNI was best. This shows that it can be important to take into account all sources of variability when using bootstrap identifiability for model selection

关键词： Positron emission tomography Kinetic theory Parameter estimation Plasma measurements Brain modeling Plasma transport processes image reconstruction Plasma sources Iterative methods Psychiatry

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Performance evaluation of iterative tomography algorithms for incomplete projection data

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APPLIED OPTICS 2004年第7期43卷 1522-1532页

作者： Mishra, D Longtin, JP Singh, RP Prasad, v SUNY Stony Brook Dept Mech Engn Stony Brook NY 11794 USA Florida Int Univ Dept Mech Engn Miami FL 33174 USA

Projection data obtained through optical techniques for tomographic measurements, such as interferometry for refractive-index-based measurements, are often incomplete. This is due to limitations in the optical system, data storage, and alignment and vignette issues. Algebraic iterative reconstruction techniques are usually favored for such incomplete projections. A number of iterative algorithms, based on additive and multiplicative corrections, are used with a known simulated phantom and noise source to assess the reconstruction performance of incomplete data sets. In addition, we present reconstructions using experimental data obtained from a coherent gradient sensing interferometer for a steady temperature field in a fluid medium. We tested the algorithms using the simulated data set for incompleteness conditions similar to those found in the experimental data, and the best-performing algorithm is identified. (C) 2004 Optical Society of America.

关键词： Cylindrical lenses image reconstruction Laser beams Phase shift reconstruction algorithms Three dimensional measurement

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