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Online tracking of deformable objects under occlusion using dominant points

JOURNAL OF THE optical SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2013年第8期30卷 1484-1491页

作者： Prasad, Dilip K. Brown, Michael S. Natl Univ Singapore Sch Comp Singapore 117417 Singapore

This paper deals with tracking of deformable objects in the presence of occlusion using dominant point representation of the boundary contour. A novel nonintegral time propagation model for propagating the dominant points is proposed. It uses an initial guess generated from a linear operation and an analytical conjugate gradient approach for online robust learning of the shape deformation and motion model. A scheme is presented to automatically detect and correct the region of large local deformation. In order to deal with occlusion, admissible restrictions on deformation and motion of the object are automatically determined. The proposed method overcomes the need of offline learning and learns the deformation and motion model of the object using very few initial frames of the input video. The performance of the method is demonstrated using varieties of videos of different objects. (C) 2013 optical Society of America

关键词： Numerical approximation and analysis digital image processing Image analysis pattern recognition

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A survey on skeletons in digital image processing

A survey on skeletons in digital image processing

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2009 International Conference on digital Image Processing

作者： Lakshmi, J.Komala Punithavalli, M. Department of Computer science SNR SONS college Coimbatore India Department of computer scince SriRamakrishna college of arts and science for women Coimbatore India

ISBN: (纸本)9780769535654

An image is digitized to convert it to a form which can be stored in a computer's memory or on some form of storage media such as a hard disk or CD-ROM. Once the image has been digitized, it can be operated upon by various image processing operations like enhancement, restoration, reconstruction, compression. An image defined in the "real world" is considered to be a function of two real variables, for example, a(x,y) with a as the amplitude (e.g. brightness) of the image at the real coordinate position (x,y). An image may be considered to contain sub-images sometimes referred to as regions-of-interest, ROIs, or simply regions. This concept reflects the fact that images frequently contain collections of objects each of which can be the basis for a region. In a sophisticated image processing system it should be possible to apply specific image processing operations to selected regions. Thus one part of an image (region) might be processed to suppress motion blur while another part might be processed to improve color rendition. For performing image processing operations ,the basic structure called skeleton is much more essential and highly adaptive tool. Skeletons are important shape descriptors in object representation and recognition. A skeleton that captures essential topology and shape information of the object in a simple form is extremely useful in solving various problems such as character recognition, 3D model matching and retrieval, and medical image analysis. Medical imaging systems. Due to its compact shape representation, image skeleton has been studied for a long time in computer vision, pattern recognition, and optical character recognition. It is a powerful tool for intermediate representation for a number of geometric operations on solid models. Many image processing applications depend on the skeletons. © 2009 IEEE.

关键词： Image enhancement

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Three-dimensional shape measurement based on Fourier transform and phase shifting method

Three-dimensional shape measurement based on Fourier transfo...

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作者： Guo, Hong State University of New York at Stony Brook

学位级别：Ph.D.

Phase shifting method and the Fourier transform method are both fringe analysis methods. This dissertation research focuses on utilizing these two methods to extract 3-D shape information encoded in fringe patterns obtained from digital fringe projection technique and shadow moiré technique respectively. A modified Fourier transform method is developed for real-time 3-D shape measurement of dynamic objects based on the digital fringe projection technique. A phase shifting scheme is developed for the shadow moiré technique in effort to improve its resolution and accuracy. A novel face recognition method is proposed, which employs phase shifting method and the Fourier transform method to obtain an efficient spectral representation of 3-D face. digital fringe projection technique is a full-field, high-resolution, and high-speed 3-D shape measurement method. Real-time fringe pattern acquisition, processing, and 3-D display by use of 3-step phase shifting method has been previously achieved on a high-speed digital fringe projection system. However, measurement of fast moving or changing objects remains difficult in that at least three fringe patterns taken over time are required. Although the Fourier transform method only needs one frame of fringe pattern, the measurement quality is limited when objects with complex shapes are measured. In this research, a modified Fourier method is proposed, which aims at measuring dynamic objects with complex shapes. The basic idea is to acquire a flat image in addition to a fringe image, which provides necessary information for overcoming the shortcomings of the conventional Fourier transform method. Two fringe projection schemes are proposed and compared. The experimental results demonstrated that the proposed method can be used for real-time 3-D shape measurement of complex shapes, and improved measurement quality over 3-step phase shifting method is achieved. Shadow moiré is a traditional full-field optical 3-D shape measurement te

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3-D shape Measurement Based on Fourier Transform and Phase Shifting Method

3-D Shape Measurement Based on Fourier Transform and Phase S...

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作者： Hong Guo Stony Brook University

学位级别：博士

Phase shifting method and the Fourier transform method are both fringe analysis methods. This dissertation research focuses on uti- lizing these two methods to extract 3-D shape information encoded in fringe patterns obtained from digital fringe projection tech- nique and shadow moire technique respectively. A modified Fourier transform method is developed for real-time 3-D shape measure- ment of dynamic objects based on the digital fringe projection technique. A phase shifting scheme is developed for the shadow moire technique in effort to improve its resolution and accuracy. A novel face recognition method is proposed, which employs phase shifting method and the Fourier transform method to obtain an efficient spectral representation of 3-D face. digital fringe projection technique is a full-field, high-resolution, and high-speed 3-D shape measurement method. Real-time fringe pattern acquisition, processing, and 3-D display by use of 3-step phase shifting method has been previously achieved on a high- speed digital fringe projection system. However, measurement of fast moving or changing objects remains difficult in that at least three fringe patterns taken over time are required. Although the Fourier transform method only needs one frame of fringe pattern, the measurement quality is limited when objects with complex shapes are measured. In this research, a modified Fourier method is proposed, which aims at measuring dynamic objects with com- plex shapes. The basic idea is to acquire a flat image in addi- tion to a fringe image, which provides necessary information for overcoming the shortcomings of the conventional Fourier trans- form method. Two fringe projection schemes are proposed and compared. The experimental results demonstrated that the pro- posed method can be used for real-time 3-D shape measurement of complex shapes, and improved measurement quality over 3-step phase shifting method is achieved. Shadow moire is a traditional full-field optical 3-D shape

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Analysis and representation of Character Images for Extracting shape based Features Towards Building an OCR for Bangla Script

Analysis and Representation of Character Images for Extracti...

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International Conference on digital Image Processing, ICDIP

作者： M.A. Naser M.A. Hasnat T. Latif S.M. Nizamuddin T. Islam Department of Electrical and Electronic Engineering Islamic University of Technology Dhaka Bangladesh Center for Research on Bangla Language Processing BRAC University Dhaka Bangladesh Department of Electronic Engineering King''s College UK

In this paper we present the analysis of different representation techniques of the character images for extracting shape based features using modified signature method. An adaptive normalization is proposed that retains the aspect ratio of the character which is subjected to the fact that preservation of aspect ratio enhances the recognition process. Signature is generated from direction angle of the pixels where the pixels were taken from boundary, difference and skeletonized image of the character. Correlation among the extracted features for 13 different fonts of all 50 characters is analyzed. We measured the recognition performance of different representation approaches.

关键词： Image analysis shape Feature extraction optical character recognition software Pixel pattern recognition digital images Educational institutions Character recognition Character generation

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A Survey on Skeletons in digital Image Processing

A Survey on Skeletons in Digital Image Processing

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International Conference on digital Image Processing, ICDIP

作者： J. Komala Lakshmi M. Punithavalli Department of Computer science SNR SONS college Coimbatore Department of computer scince SriRamakrishna college of arts and science for women Coimbatore India

关键词： Skeleton digital images Image processing shape Image storage Character recognition Power system modeling Biomedical imaging Image converters Hard disks

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Novel feature representation and *matching techniques for content -based image retrieval

Novel feature representation and *matching techniques for co...

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作者： Wang, Zhiyong Hong Kong Polytechnic University (Hong Kong)

学位级别：Ph.D.

This thesis presents novel feature representation schemes and matching techniques for content-based image retrieval. There are three main contributions reported in the thesis. They include: (1) a block-constrained fractal coding scheme and an improved nona-tree decomposition based matching technique for image retrieval; (2) a thinning-based starting point localization method and the application of a fuzzy integral to the combination of different shape feature sets for plant leaf image retrieval; and (3) tree-structured content representation and its adaptive processing for content-based image retrieval with relevance feedback. In the first investigation, an image is partitioned into non-overlap blocks of a size similar to that of an iconic query image. Fractal code is efficiently generated for each block individually. For the similarity measure in matching the fractal code of two images, an improved nona-tree decomposition scheme is adopted to avoid matching the fractal code globally so as to significantly reduce computational complexity. In the second investigation, a robust fuzzy integral method is used to combine three shape feature sets, namely, centroid-contour distance (CCD) curve, moment invariants (MIs), and angle code histogram (ACH), for shape-based plant leaf image retrieval. Different from MIs and the ACH feature set, the CCD curve is neither scale nor rotation invariant. Hence, a normalization scheme is needed for the CCD curve to achieve scale invariance, and an efficient starting point localization method is required to achieve the rotation invariance with the similarity measure of CCD curves. In this investigation, a thinning-based method is proposed to locate possible starting points of a leaf contour to make our approach more computationally efficient for image matching. Our proposed starting point localization method can also benefit other shape representation schemes that are sensitive to starting points. In order to combine the three feature set

关键词： Hong Kong Polytechnic University -- Dissertations Image processing -- digital techniques optical pattern recognition

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Skeletonization applied to magnetic resonance angiography images

Skeletonization applied to magnetic resonance angiography im...

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Medical Imaging 1998 Conference on Image Processing

作者： Nystrom, I Uppsala Univ Ctr Image Anal SE-75237 Uppsala Sweden

ISBN: (纸本)0819427837

When interpreting and analysing magnetic resonance angiography images, the 3D overall tree structure and the thickness of the blood vessels are of interest. This shape information may be easier to obtain from the skeleton of the blood vessels. Skeletonization of digital volume objects denotes either reduction to a 2D structure consisting of 3D surfaces and curves, or reduction to a 1D structure consisting of 3D curves only. Thin elongated objects, such as blood vessels, are well suited for reduction to curve skeletons. Our results indicate that the tree structure of the vascular system is well represented by the skeleton. Positions for possible artery stenoses may be identified by locating local minima in curve skeletons, where the skeletal voxels are labelled with the distance to the original background.

关键词： pattern recognition shape representation skeleton digital topology MR angiography artery stenosis diagnosis application

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CONTINUOUS SCALE-INVARIANT optical COMPOSITE WAVELET MATCHED FILTERS WITH ADAPTIVE WAVELETS 2

CONTINUOUS SCALE-INVARIANT OPTICAL COMPOSITE WAVELET MATCHED...

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2nd Conference on Wavelet Applications

作者： ROBERGE, D SHENG, YL UNIV LAVAL DEPT PHYSCTR OPT PHOTON & LASERQUEBEC CITYPQ G1K 7P4CANADA

ISBN: (纸本)0819418447

The wavelet transform (WT) can be used for pattern recognition. One scheme is to extract the wavelet features in the 4-D space-scale joint representation of the 2-D pattern for statistical pattern recognition. Another scheme is the wavelet matched filters (WMF), that uses the WT to enhance the edge features and make correlation between the WT of the input image and the WT of the reference image. This approach uses the optical shift invariant continuous WT and implements the WT and the matching of two WTs in a single step of the correlation. Several adaptive WTs and the matching pursuits have been proposed that use the best basis functions to the signal decomposition. The basis is selected from a library of dictionary waveforms to minimize an energy or an entropy in such a way that the signal expansion with those bases is the best for signal representation or classification. pattern recognition emphasizes the classification. Fast numerical algorithms are given for the signal expansion with the best adaptive discrete orthogonal bases. Most approaches use a fixed shape basic wavelet with varying shift and dilation parameters. Szu et al., proposed adaptive wavelets that are linear combination of wavelets, called the `super-wavelet.' The super-wavelets can be continuous and redundant. The shape of the super-wavelets can be adaptively changed for the particular applications. They show the adaptive WT of the 1-D speech signals. In this paper we show the adaptive WT with continuous 2-D wavelets, whose shape is adaptively changed to achieve the pattern recognition invariant to continuous shift and scale changes. We show why such an adaptive WT is needed and how to construct the composite wavelet matched filter (CWMF) with the adaptive super-wavelet for the continuous scale invariant pattern recognition. The real-time complex valued optical filters implementation is reported in this paper.

关键词： Wavelets Composites Image filtering optical filters pattern recognition digital filtering Image enhancement Adaptive optics Fourier transforms Superposition

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AUTOMATIC representation OF BINARY IMAGES

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IEEE TRANSACTIONS ON pattern ANALYSIS AND MACHINE INTELLIGENCE 1990年第12期12卷 1190-1196页

作者： CABRELLI, CA MOLTER, UM UNIV WATERLOO DEPT APPL MATHWATERLOO N2L 3G1ONTARIOCANADA

A method of representing black and white images through the description of the boundaries of the objects that define such images is proposed. In order to obtain such a representation, this method uses several algorithms which perform boundary extraction, contour following, segmentation, pattern classification, and curve fitting. One of the advantages of this method is that the image can be reconstructed at any size. It can also be rotated or translated without losing any quality. In addition to achieving a good data-compression rate, the coding-decoding process is computationally very efficient. Also shown is the application of these algorithms to characters in order to obtain fonts that may be downloaded for modern laser printers.

关键词： Curve fitting Data mining Image segmentation Image reconstruction Data compression Laser modes Printers shape control Image coding Image analysis INSPEC: Controlled Indexing encoding computerised pattern recognition computerised picture processing data compression decoding INSPEC: Non-Controlled Indexing coding-decoding process binary image representation computerised picture processing boundary extraction contour following segmentation pattern classification curve fitting data-compression

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