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Data-dependent pre- and postprocessing multiple description coding of images

IEEE TRANSACTIONS ON image processing 2007年第5期16卷 1269-1280页

作者： Tillo, Tammam Olmo, Gabriella Politecn Torino Dept Elect I-10129 Turin Italy

Multiple description coding can be implemented as pre- and postprocessing to all standards for image and video communications, with obvious advantages. This can be achieved by generating two subsets from the original data;a controllable amount of extra redundancy between the descriptions has to be inserted to help the estimation of the possibly lost description from the received one. This redundancy can be in the form of spatial oversampling. In this paper, we propose and develop a mathematical framework for two descriptions pre- and postprocessing methods, which exploit the correlation characteristics of the visual data in order to better implement the multiple description coding paradigm. Simulation results show a noticeable performance improvement of both the proposed methods with respect to state-of-the art algorithms, in terms of both rate/redundancy/distortion tradeoff and computational complexity.

关键词： H.264 image coding JPEG2000 multiple description coding (MDC)

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Occlusion and split detection and correction for object tracking in surveillance applications

Occlusion and split detection and correction for object trac...

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Conference on visual communications and image processing 2007

作者： Vazqueza, Carlos Ghazal, Mohammed Amer, Aishy Adv Video Syt Commun Res Ctr Ottawa ON Canada Concordia Univ Elect & Comp Engn Montreal PQ Canada

ISBN: (纸本)9780819466211

This paper proposes a novel algorithm for the real-time detection and correction of occlusion and split in feature-based tracking of objects for surveillance applications. The proposed algorithm detects sudden variations of spatio-temporal features of objects in order to identify possible occlusion or split events. The detection is followed by a validation stage that uses past tracking information to prevent false detection of occlusion or split. Special care is taken in case of heavy occlusion, when there is a large superposition of objects. In this case the system relies on long-term 'temporal behavior of objects to avoid updating the video object features with unreliable (e.g. shape and motion) information. Occlusion is corrected by separating occluded objects. For the detection of splits, in addition to the analysis of spatio-temporal changes in objects features, our algorithm analyzes the temporal behavior of split objects to discriminate between errors in segmentation and real separation of objects, such as in the deposit of an object. Split is corrected by physically merging the objects detected to be split. To validate the proposed approach, objective and visual results are presented. Experimental results show the ability of the proposed algorithm to detect and correct, both, split and occlusion of objects. The proposed algorithm is most suitable in video surveillance applications due to: its good performance in multiple, heavy, and total occlusion;its distinction between real object separation and faulty object split;its handling of simultaneous occlusion and split events;and its low computational complexity.

关键词： Video Information operations Detection and tracking algorithms image segmentation Surveillance Video surveillance image processing Error analysis visualization image processing algorithms and systems

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A fidelity metric for assessing visual quality of color images

A fidelity metric for assessing visual quality of color imag...

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16th International Conference on Computer communications and Networks

作者： Chou, Chun-Hsien Liu, Kuo-Cheng Department of Electrical Engineering Tatung University Taiwan Foreign Language and Information Educating Center Taiwan Hospitality and Tourism College

ISBN: (纸本)9781424412501

Correct assessment of image fidelity is fundamental to the development of efficient image compression schemes especially to that of the schemes taking characteristics of the human visual system into account. In this paper, a fidelity metric for assessing the visual quality of color images is presented. The proposed fidelity metric is designed to measure the perceivable distortion in the quasi-uniform color space of CIELAB. To evaluate the perceptibility of distortion, a color visual model is employed to estimate the visibility threshold of distortion for each color pixel. The visibility threshold of each color is measured as the size of the sphere of just-noticeable color difference and is modeled as a function of chroma, local luminance gradient and background uniformity. Simulation results show that the assessment of the proposed fidelity metric is more correspondent with the subjective assessment than other metrics using PSNR and CIELAB Delta E.

关键词： Color image processing

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image processing TECHNIQUES FOR CORK TILES CLASSIFICATION

IMAGE PROCESSING TECHNIQUES FOR CORK TILES CLASSIFICATION

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IEEE International Conference on Signal processing and communications

作者： Georgieva, A. Jordanov, I. Univ Portsmouth Sch Comp Portsmouth PO1 2UP Hants England

ISBN: (纸本)9781424412358

An intelligent, automated visual inspection system is investigated in this paper. It is used for pattern recognition and classification of four different types of cork tiles. The process includes image acquisition with a CCD camera, texture feature extraction, statistical processing of the feature vectors, and cork tiles classification with feed-forward Neural Networks (NN) employing a hybrid global optimization technique called GLP(tau)S. We use co-occurrence method and the Laws filter masks to generate image texture characteristics. Several different NN topologies, reflecting variety of texture features are simulated, evaluated and their generalization abilities discussed and assessed. Reported test results show very encouraging recognition and classification rate of up to 95%.

关键词： Neural networks global optimization pattern recognition image processing feature extraction

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A comparative study of image compression based on directional wavelets

A comparative study of image compression based on directiona...

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Conference on visual communications and image processing 2007

作者： Li, Kun Xu, Wenli Dai, Qionghai Wang, Yao Tsinghua Univ Dept Automat Beijing 100084 Peoples R China Polytech Univ Elect & Comp Engn Dept Brooklyn NY 11201 USA

ISBN: (纸本)9780819466211

Discrete wavelet transform is an effective tool to generate scalable stream, but it cannot efficiently represent edges which are not aligned in horizontal or vertical directions, while natural images often contain rich edges and textures of this kind. Hence, recently, intensive research has been focused particularly on the directional wavelets which can effectively represent directional attributes of images. Specifically, there are two categories of directional wavelets: redundant wavelets (RW) and adaptive directional wavelets (ADW). One representative redundant wavelet is the dual-tree discrete wavelet transform (DDWT), while adaptive directional wavelets can be further categorized into two types: with or without side information. In this paper, we briefly introduce directional wavelets and compare their directional bases and image compression performances.

关键词： scalable image coding discrete wavelet transform directional wavelets redundant wavelets dual-tree discrete wavelet transform adaptive directional wavelets side information basis functions compression performances context-based arithmetic coding

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EDGE MODELING PREDICTION FOR COMPUTED TOMOGRAPHY imageS

EDGE MODELING PREDICTION FOR COMPUTED TOMOGRAPHY IMAGES

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IEEE visual communications and image processing (VCIP)

作者： Weinlich, Andreas Amon, Peter Hutter, Andreas Kaup, Andre Univ Erlangen Nurnberg D-91054 Erlangen Germany Siemens Corp Technol Imaging & Comp Vis Munich Germany

ISBN: (纸本)9781467344050;9781467344067

Predictive coding is applied in many state-of-the-art loss-less image compression algorithms like JPEG-LS, CALIC, or least-squares-based methods. We propose a new approach for accurate intensity prediction in pixel-predictive coding of computed tomography (CT) images. Exploiting their particular edge characteristic, the method only relies on a small twelve-pixel context. It does neither require adaptation to larger-region image characteristics nor the transmission of side-information and therefore may be particularly suitable for compression of small images like in region-of-interest coding. While applying simple linear prediction with fixed weights in homogeneous regions, a Gauss error model-function is fit to given contexts in edge regions and then sampled at the position corresponding to the pixel to be predicted in order to obtain prediction values. By the example of CALIC, it is shown that for CT data the edge modeling prediction (EMP) approach can yield an even smaller prediction error than other methods relying on context modeling.

关键词： Edge modeling prediction predictive coding lossless medical image compression X-ray computed tomography Gauss error function fitting

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AUTOMATIC ANNOTATION OF DIGITAL imageS USING COLOUR STRUCTURE AND EDGE DIRECTION

AUTOMATIC ANNOTATION OF DIGITAL IMAGES USING COLOUR STRUCTUR...

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IEEE International Conference on Signal processing and communications

作者： Shao, Wenbin Naghdy, Golshah Phung, Son Lam Univ Wollongong Sch Elect Comp & Telecommun Engn Wollongong NSW 2522 Australia

ISBN: (纸本)9781424412358

The focus of this paper is on automatic annotation for semantic image retrieval. This work is aimed at identifying visual descriptors that are most relevant, effective and suitable for semantic annotation tasks. We propose an image annotation system based on support vector machines and a combination of descriptors that includes a gradient direction histogram and several MPEG-7 visual descriptors. The system is tested on a large database of 7200 cityscape and landscape images. The results indicate that when descriptors are used individually, the proposed gradient direction histogram performs best. However, when descriptors are combined, the accuracy is improved. The presented results confirm that combining the gradient direction histogram and colour structure produces the best results.

关键词： image classification SVMs MPEG-7 gradient direction histogram

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A ROBUST CHAOTIC image WATERMARKING TECHNIQUE BASED ON HVS AND DIFFERENTIAL AFFINE MOTION ESTIMATION

A ROBUST CHAOTIC IMAGE WATERMARKING TECHNIQUE BASED ON HVS A...

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IEEE International Conference on Signal processing and communications

作者： Bouab, Mohammed Khamadja, Mohammed Amira-Biad, Souad SP Lab. Electronics Dept. Mentouri University of Constantine 25000 Algeria

ISBN: (纸本)9781424412358

This paper deals with the insertion of a chaotic signature in an image by exploiting the analogy presented by the wavelets transform and the human visual system (HVS) model, to modulate and adapt the signature according to local characteristic's of the image. The blind detection process consists on computing the correlation between the marked DWT coefficients and the watermarking sequence. In order to face the problem of the geometrical de-synchronization, a differential technique of motion estimation is employed to compensate the possible geometrical deformations undergone by the watermarked image. The method has been proved to be robust to various image processing such as compression, filtering and noise addition and various geometrical attacks such as translation, rotation, scaling, cropping and resizing.

关键词： watermarking wavelet decomposition HVS chaotic sequence blind detection image registration

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Progressive image transmission with RCPT protection

Progressive image transmission with RCPT protection

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Conference on visual communications and image processing 2007

作者： Yao, Lei Cao, Lei Chen, Chang Wen Univ Mississippi Dept Elect Engn University MS 38677 USA Florida Inst Technol Dept Elect & Comp Engn Melbourne FL 32901 USA

ISBN: (纸本)9780819466211

In this paper, a joint source-channel coding scheme is proposed for progressive image transmission over channels with both random bit errors and packet loss by using rate-compatible punctured Turbo codes (RCPT) protection only. Two technical components which are different from existing methods are presented. First, a data frame is divided into multiple CRC blocks before being coded by a turbo code. This is to secure a high turbo coding gain which is proportional to the data frame size. In the mean time, the beginning blocks in a frame may still be usable although the decoding of the entire frame fails. Second, instead of employing product codes, we only use RCPT, along with an interleaver, to protect images over channels with combined distortion including random errors and packet loss. With this setting, the effect of packet loss is equivalent to randomly puncturing turbo codes. As a result, the optimal allocation of channel code rates is required for the random errors only, which largely reduces the complexity of the optimization process. The effectiveness of the proposed schemes is demonstrated with extensive simulation results.

关键词： progressive image transmission source-channel coding multiple CRC RCPT interleaving

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Optimal multiple sprite generation based on physical camera parameter estimation

Optimal multiple sprite generation based on physical camera ...

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Conference on visual communications and image processing 2007

作者： Kunter, Matthias Krutz, Andreas Mandal, Mrinal Sikora, Thomas Tech Univ Berlin Commun Syst Grp Einsteinufer 17 D-10587 Berlin Germany Univ Alberta Dept Elect & Comp Engn Edmonton AB T6G 2V4 Canada

ISBN: (纸本)9780819466211

We present a robust and computational low complex method to estimate the physical camera parameters, intrinsic and extrinsic, for scene shots captured by cameras applying pan, tilt, rotation, and zoom. These parameters are then used to split a sequence of frames into several subsequences in an optimal way to generate multiple sprites. Hereby, optimal means a minimal usage of memory while keeping or even improving the reconstruction quality of the scene background. Since wide angles between two frames of a scene shot cause geometrical distortions using a perspective mapping it is necessary to part the shot into several subsequences. In our approach it is not mandatory that all frames of a subsequence are adjacent frames in the original scene. Furthermore the angle-based classification allows frame reordering and makes our approach very powerful.

关键词： camera calibration image mosaicing multiple sprites sprite generation

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