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Circuits and Systems for Video Technology, IEEE Transactions on

Issue 4 • Date June 1999

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Displaying Results 1 - 13 of 13
  • A pyramidal image coder using generalized rank-ordered prediction filter

    Publication Year: 1999 , Page(s): 540 - 544
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (157 KB)  

    This paper presents a lossy image compression scheme that employs a generalized rank-ordered prediction filter for pyramidal image coding. The proposed prediction method renders significantly reduced variance of the quantizer input. Consequently, the quality of the decompressed image is much enhanced due to the greatly reduced quantization distortion. Both analytical and simulation results show that the proposed scheme yields high-quality performance. View full abstract»

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  • Covariance analysis of motion-compensated frame differences

    Publication Year: 1999 , Page(s): 536 - 539
    Cited by:  Papers (16)  |  Patents (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    The second-order statistics of motion-compensated frame differences in a low-bit-rate hybrid video coding scheme with overlapped block motion compensation are investigated. Based on the empirical covariance sequence, an adequate compound covariance model is developed. The prediction gain for motion-compensated frame differences is evaluated, and the performance of the discrete cosine transform for interframe transform coding is discussed View full abstract»

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  • Face segmentation using skin-color map in videophone applications

    Publication Year: 1999 , Page(s): 551 - 564
    Cited by:  Papers (194)  |  Patents (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (696 KB)  

    This paper addresses our proposed method to automatically segment out a person's face from a given image that consists of a head-and-shoulders view of the person and a complex background scene. The method involves a fast, reliable, and effective algorithm that exploits the spatial distribution characteristics of human skin color. A universal skin-color map is derived and used on the chrominance component of the input image to detect pixels with skin-color appearance. Then, based on the spatial distribution of the detected skin-color pixels and their corresponding luminance values, the algorithm employs a set of novel regularization processes to reinforce regions of skin-color pixels that are more likely to belong to the facial regions and eliminate those that are not. The performance of the face-segmentation algorithm is illustrated by some simulation results carried out on various head-and-shoulders test images. The use of face segmentation for video coding in applications such as videotelephony is then presented. We explain how the face-segmentation results can be used to improve the perceptual quality of a videophone sequence encoded by the H.261-compliant coder View full abstract»

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  • Multiresolution watermarking for images and video

    Publication Year: 1999 , Page(s): 545 - 550
    Cited by:  Papers (45)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    This paper proposes a unified approach to digital watermarking of images and video based on the two- and three-dimensional discrete wavelet transforms. The hierarchical nature of the wavelet representation allows multiresolutional detection of the digital watermark, which is a Gaussian distributed random vector added to all the high-pass bands in the wavelet domain. We show that when subjected to distortion from compression or image halftoning, the corresponding watermark can still be correctly identified at each resolution (excluding the lowest one) in the wavelet domain. Computational savings from such a multiresolution watermarking framework is obvious, especially for the video case View full abstract»

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  • Automated high-level movie segmentation for advanced video-retrieval systems

    Publication Year: 1999 , Page(s): 580 - 588
    Cited by:  Papers (80)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB)  

    We present a newly developed strategy for automatically segmenting movies into logical story units. A logical story unit can be understood as an approximation of a movie episode, which is a high-level temporal movie segment, characterized either by a single event (dialog, action scene, etc.) or by several events taking place in parallel. Since we consider a whole event and not a single shot to be the most natural retrieval unit for the movie category of video programs, the proposed segmentation is the crucial first step toward a concise and comprehensive content-based movie representation for browsing and retrieval purposes. The automation aspect is becoming increasingly important with the rising amount of information to be processed in video archives of the future. The segmentation process is designed to work on MPEG-DC sequences, where we have taken into account that at least a partial decoding is required for performing content-based operations on MPEG compressed video streams. The proposed technique allows for carrying out the segmentation procedure in a single pass through a video sequence View full abstract»

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  • Average optimal vector transform for VQ-based image and video compression

    Publication Year: 1999 , Page(s): 617 - 629
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    We present an average sense optimal vector transform (AOVT) for vector quantization (VQ)-based coding of square block vectors. We introduce new notions of average intervector correlations and exploit the new structure of the intervector correlation matrix in deriving our AOVT. We present the results of applying our AOVT to many real images and demonstrate the superiority of the AOVT in terms of better preservation of the intravector correlation in the transform domain. We also present coding results on a variety of images to demonstrate the fact that the above-mentioned advantage of AOVT translates into coding gains since the performance of VQ increases if the transform domain vectors have more intravector dependencies View full abstract»

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  • Disparity/segmentation analysis: matching with an adaptive window and depth-driven segmentation

    Publication Year: 1999 , Page(s): 589 - 607
    Cited by:  Papers (29)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1888 KB)  

    Most of the emerging content-based multimedia technologies are based on efficient methods to solve machine early vision tasks. Among other tasks, object segmentation is perhaps the most important problem in single image processing, whereas pixel-correspondence estimation is the crucial task in multiview image analysis. The solution of these two problems is the key for the development of the majority of leading-edge interactive video-communication technologies and telepresence systems. In this paper, we present a robust framework comprised of joined pixel-correspondence estimation and image segmentation in video sequences taken simultaneously from different perspectives. An improved concept for stereo-image analysis based on block matching with a local adaptive window is introduced. The size and shape of the reference window is calculated adaptively according to the degree of reliability of disparities estimated previously. Considerable improvements are obtained just within object borders or image areas that become occluded by applying the proposed block-matching model. An initial object segmentation is obtained by merging neighboring sampling positions with disparity vectors of similar size and direction. Starting from this initial segmentation, true object borders are detected using a contour-matching algorithm. In this process, the contour of the initial segmentation is taken as a reference pattern, and the edges extracted from the original images, by applying a multiscale algorithm, are the candidates for the true object contour. The performance of the introduced methods has been verified View full abstract»

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  • Modeling DCT coefficients for fast video encoding

    Publication Year: 1999 , Page(s): 608 - 616
    Cited by:  Papers (87)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    Digital video coding standards such as H.263 and MPEG are becoming more and more important for multimedia applications. Due to the huge amount of computations required, there are significant efforts to speed up the processing of video encoders. Previously, the efforts were mainly focused on the fast motion-estimation algorithm. However, as the motion-estimation algorithm becomes optimized, to speed up the video encoders further we also need to optimize other functions such as the discrete cosine transform (DCT) and inverse DCT (IDCT). In this paper, we propose a theoretical model for DCT coefficients. Based on the model, we develop an adaptive algorithm to reduce the computations of DCT, IDCT, quantization, and inverse quantization. We also present a fast DCT algorithm to speed up the calculations of DCT further when the quantization step size is large. We show, by simulations, that significant improvement in the processing speed can be achieved with negligible video-quality degradation, We also implement the algorithm in a real-time PC-based platform to show that it is effective and practical View full abstract»

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  • An adaptive quantization algorithm for video coding

    Publication Year: 1999 , Page(s): 527 - 535
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    This paper proposes an adaptive quantization algorithm for video coding using the information obtained from the previously encoded image. Before quantizing the discrete cosine transform coefficients, the properties of reconstruction error of each macro block (MB) are estimated from the previous frame. For the estimation of the error of current MB, a block with the size of MB in the previous frame is chosen. Since the original and reconstructed images of the previous frame are available in the encoder, we can evaluate the tendency of reconstruction error of this block in advance. Then, this error is considered as the expected error of the current MB if it is quantized with the same step size and bit rate. Comparing the error of the MB with the average of overall MBs, if it is larger than the average, a small step size is given for this MB, and vice versa. As a result, the error distribution of the MB is more concentrated to the average, yielding low variance and improved image quality. Especially for low bit applications, the proposed algorithm yields much smaller error variance and higher peak signal-to-noise ratio compared to the conventional TM5. We also propose a modified algorithm for efficient hardware implementation View full abstract»

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  • Architecture and design of a Talisman-compatible multimedia processor

    Publication Year: 1999 , Page(s): 565 - 579
    Cited by:  Papers (1)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (700 KB)  

    This paper describes the architecture, functionality, and design of a Talisman-compatible multimedia processor (TM-PC) from Philips Semiconductors. “Talisman” is the code name of a new graphics and multimedia hardware architecture (from Microsoft Corp.) that aims at achieving the performance of high-end three-dimensional graphics workstations at consumer price points. The TM-PC is a programmable processor with a high-performance, very long instruction word central processing unit (CPU) core. The CPU core, aided by an array of peripheral devices (multimedia coprocessors and input-output units), facilitates concurrent processing of audio, video, graphics, and communication data. Designed specifically for the Microsoft Talisman project, TM-PC is a derivative of Philips' TM-1 media processor and is tailored to be used in a variety of PC-based functions as a plug-in board on the peripheral component interconnect (PCI) bus. In the design of the TM-PC, the functionality of most of the blocks from the TM-1 has been kept unchanged; the primary changes in the existing blocks have been in the main memory and the PCI interfaces, and a new block, called VPB, has been added to support virtual frame buffer functionality as well as video graphics adapter and Soundblaster emulation capability. The major emphasis of this paper is on the design details of the new VPB module and an explanation of how it fits with the rest of the TM-1 design View full abstract»

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  • Low-delay, low-complexity rate reduction and continuous presence for multipoint videoconferencing

    Publication Year: 1999 , Page(s): 666 - 676
    Cited by:  Papers (6)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    We propose new methods and architecture for low-delay, low-complexity video bit-rate reduction and continuous presence for multipoint videoconferencing. Rate reduction is performed in the discrete cosine transform (DCT) domain to achieve both low delay and low complexity. Requantization is applied to the originally quantized DCT coefficients, and the requantization errors are stored in a frame buffer in the DCT domain instead of the pixel domain. Skipped macroblocks in the original coded bitstream are processed to improve picture quality. The QCIP-to-CIF combiner is used to realize continuous presence. Asymmetric frame rates and pipelined combination on the group-of-blocks level lead to significantly reduced insertion delay compared to the published methods in the literature. Both simulation and real-time implementation results are reported to validate the proposed methods and architecture View full abstract»

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  • Geometric-structure-based error concealment with novel applications in block-based low-bit-rate coding

    Publication Year: 1999 , Page(s): 648 - 665
    Cited by:  Papers (48)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1320 KB)  

    This paper first proposes a computationally efficient spatial directional interpolation scheme, which makes use of the local geometric information extracted from the surrounding blocks. The proposed error-concealment scheme produces results that are superior to those of other approaches, in terms of both peak signal-to-noise ratio and visual quality. Then a novel approach that incorporates this directional spatial interpolation at the receiver is proposed for block-based low-bit-rate coding. The key observation is that the directional spatial interpolation at the receiver can reconstruct faithfully a large percentage of the blocks that are intentionally not sent. A rate-distortion optimal way to drop the blocks is shown. The new approach can be made compatible with standard JPEG and MPEG decoders. The block-dropping approach also has an important application for dynamic rate shaping in transmitting precompressed videos over channels of dynamic bandwidth. Experimental results show that the proposed coding and rate-shaping systems can provide significant subjective and objective gains over conventional approaches View full abstract»

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  • Significance-linked connected component analysis for very low bit-rate wavelet video coding

    Publication Year: 1999 , Page(s): 630 - 647
    Cited by:  Papers (7)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (880 KB)  

    A novel hybrid wavelet video coding algorithm termed video significance-linked connected component analysis (VSLCCA) is developed for very low bit-rate applications. In the proposed VSLCCA codec, first, fine-tuned motion estimation based on the H.263 Recommendation is developed to reduce temporal redundancy, and exhaustive overlapped block motion compensation is utilized to ensure coherency in motion compensated error frames. Second, the wavelet transform is applied to each coherent motion compensated error frame to attain global energy compaction. Third, significant fields of wavelet-transformed error frames are organized and represented as significance-linked connected components so that both the within-subband clustering and the cross-scale dependency are exploited. Last, the horizontal and vertical components of motion vectors are encoded separately using adaptive arithmetic coding while significant wavelet coefficients are encoded in bit-plane order by using high order Markov source modeling and adaptive arithmetic coding. Experimental results on eight standard MPEG-4 test sequences show that for intraframe coding, on average the proposed codec exceeds H.263 and ZTE (zero-tree entropy) in peak signal-to-noise ratio by as much as 2.07 and 1.38 dB at 28 kbit/s, respectively. For entire sequence coding, VSLCCA is superior to H.263 and ZTE by 0.35 and 0.71 dB on average, respectively View full abstract»

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Aims & Scope

The emphasis is focused on, but not limited to:
1. Video A/D and D/ A
2. Video Compression Techniques and Signal Processing
3. Multi-Dimensional Filters and Transforms
4. High Speed Real-Tune Circuits
5. Multi-Processors Systems—Hardware and Software
6. VLSI Architecture and Implementation for Video Technology 

 

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Dan Schonfeld
Multimedia Communications Laboratory
ECE Dept. (M/C 154)
University of Illinois at Chicago (UIC)
Chicago, IL 60607-7053
tcsvt-eic@tcad.polito.it

Managing Editor
Jaqueline Zelkowitz
tcsvt@tcad.polito.it