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Circuits and Systems for Video Technology, IEEE Transactions on

Issue 10 • Date Oct. 2002

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Displaying Results 1 - 14 of 14
  • A new compression scheme for color-quantized images

    Publication Year: 2002 , Page(s): 904 - 908
    Cited by:  Papers (7)  |  Patents (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB) |  | HTML iconHTML  

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  • The performance of H263-based video telephony over turbo-equalized GSM/GPRS

    Publication Year: 2002 , Page(s): 909 - 915
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (483 KB) |  | HTML iconHTML  

    The performance of turbo-equalized Global System of Mobile Communications/General Packet Radio Service (GSM/GPRS)-like videophone transceivers is studied over dispersive fading channels as a function of the number of turbo equalization iterations. Iteration gains up to 6 dB were attained. The operating channel signal-to-noise ratio (SNR) required for maintaining a peak SNR loss of less than 1 dB was reduced by 3.2 dB for the one-slot system and by 4.1 dB for the four-slot system. The proposed system is capable of providing low-resolution videophone services over GSM/GPRS. View full abstract»

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  • Reliable information bit hiding

    Publication Year: 2002 , Page(s): 916 - 920
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (313 KB) |  | HTML iconHTML  

    One of challenges encountered in information bit hiding is the reliability of information bit detection. This paper addresses the issue and presents an algorithm in the discrete cosing transform (DCT) domain with a communication theory approach. It embeds information bits (first) in the DC and (then in the) low-frequency AC coefficients. To extract the hidden information bits from a possibly corrupted marked image with a low error probability, we model information hiding as a digital communication problem and apply Bose??Chaudhuri??Hocquenghen channel coding with soft-decision decoding based on matched filtering. The robustness of the hidden bits has been tested with StirMark. The experimental results demonstrate that the embedded information bits are perceptually transparent and can successfully resist common signal processing procedures, jitter attack, aspect ratio variation, scaling change, small angle rotation, small amount cropping, and JPEG compression with quality factor as low as 10. Compared with some information hiding algorithms reported in the literature, it appears that the hidden information bits with the proposed approach are relatively more robust. While the approach is presented for gray level images, it can also be applied to color images and video sequences. View full abstract»

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  • Novel sequential error-concealment techniques using orientation adaptive interpolation

    Publication Year: 2002 , Page(s): 857 - 864
    Cited by:  Papers (78)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (801 KB)  

    This paper introduces a new framework for error concealment in block-based image coding systems: sequential recovery. Unlike previous approaches that simultaneously recover the pixels inside a missing block, we propose to recover them in a sequential fashion such that the previously-recovered pixels can be used in the recovery process afterwards. The principal advantage of the sequential approach is the improved capability of recovering important image features brought by the reduction in the complexity of statistical modeling, i.e., from blockwise to pixelwise. Under the framework of sequential recovery, we present an orientation adaptive interpolation scheme derived from the pixelwise statistical model. We also investigate the problem of error propagation with sequential recovery and propose a linear merge strategy to alleviate it. Extensive experimental results are used to demonstrate the improvement of the proposed sequential error-concealment technique over previous techniques in the literature. View full abstract»

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  • Artifact reduction in compressed images based on region homogeneity constraints using the projection onto convex sets algorithm

    Publication Year: 2002 , Page(s): 891 - 897
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1003 KB) |  | HTML iconHTML  

    A novel protection onto convex sets (POCS) method is presented for the suppression of blocking and ringing artifacts in a compressed image that contains homogeneous regions. A new family of convex smoothness constraint sets is introduced, using the uniformity property of image regions. This set of constraints allows different degrees of smoothing in different regions of the image, while preserving the image edges. The regions are segmented using the fuzzy c-means algorithm, which allows ambiguous pixels to be left unclassified. Experimental results on JPEG compressed images demonstrate that the proposed algorithm yields visually superior images compared to several of the previously reported POCS deblocking algorithms for the class of images considered. View full abstract»

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  • Subband-adaptive turbo-coded OFDM-based interactive video telephony

    Publication Year: 2002 , Page(s): 829 - 839
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (801 KB) |  | HTML iconHTML  

    A range of adaptive orthogonal frequency division multiplex (AOFDM) video systems are proposed for interactive communications over wireless channels. The proposed constant target bit-rate subband-adaptive OFDM modems can provide a lower bit error rate than a corresponding conventional OFDM modem. The slightly more complex switched or time-variant target bit rate AOFDM modems can provide a balanced video quality performance, across a wider range of channel signal-to-noise ratios, maintaining the best video performance. Upon invoking the technique advocated, irrespective of the channel conditions experienced, the transceiver achieves always the best possible video quality by automatically adjusting the achievable bit rate and the associated video quality in order to match the channel quality experienced. This is achieved on a near-instantaneous basis under given propagation conditions in order to cater for the effects of path-loss, fast-fading, slow-fading, dispersion, etc. Furthermore, when the mobile is roaming in a hostile outdoor propagation environment, typically low-order, low-rate modem modes are invoked, while in benign indoor environments predominantly the high-rate, high source-signal representation quality modes are employed. View full abstract»

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  • Optimum bit allocation and accurate rate control for video coding via ρ-domain source modeling

    Publication Year: 2002 , Page(s): 840 - 849
    Cited by:  Papers (81)  |  Patents (39)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (607 KB) |  | HTML iconHTML  

    We present a new framework for rate-distortion (R-D) analysis, where the coding rate R and distortion D are considered as functions of ρ which is the percentage of zeros among the quantized transform coefficients. Previously (see He, Z. et al., Int. Conf. Acoustics, Speech and Sig. Proc., 2001), we observed that, in transform coding of images and videos, the rate function R(ρ) is approximately linear. Based on this linear rate model, a simple and unified rate control algorithm was proposed for all standard video coding systems, such as MPEG-2, H.263, and MPEG-4. We further develop a distortion model and an optimum bit allocation scheme in the ρ domain. This bit allocation scheme is applied to MPEG-4 video coding to allocate the available bits among different video objects. The bits target of each object is then achieved by our ρ-domain rate control algorithm. When coupled with a macroblock classification scheme, the above bit allocation and rate control scheme can also be applied to other video coding systems, such as H.263, at the macroblock level. Our extensive experimental results show that the proposed algorithm controls the encoder bit rate very accurately and improves the video quality significantly (by up to 1.5 dB). View full abstract»

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  • FAP extraction using three-dimensional motion estimation

    Publication Year: 2002 , Page(s): 865 - 876
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1334 KB) |  | HTML iconHTML  

    An integral part of the MPEG-4 standard is the definition of face animation parameters (FAPs). This paper presents a method for the determination of FAPs by using three dimensional (3-D) rigid and nonrigid motion of human facial features found from two-dimensional (2-D) image sequences. The proposed method assumes that a 3-D model has been fitted to the first frame of the sequence, tracks the motion of characteristic facial features, calculates the 3-D rigid and nonrigid motion of facial features, and through this, estimates the FAPs as defined by the MPEG-4 coding standard. The 2-D tracking process is based on a novel enhanced version of the algorithm proposed by Kanade, Lucas, and Tomasi (1994, 1991). The nonrigid motion estimation is achieved using the same tracking mechanism guided by the facial motion model implied by the MPEG-4 FAPs. View full abstract»

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  • Computation reduction for motion search in low rate video coders

    Publication Year: 2002 , Page(s): 948 - 951
    Cited by:  Papers (31)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (363 KB) |  | HTML iconHTML  

    In this paper, computation reduction algorithms of motion estimation are developed for low rate video coders. By jointly considering motion estimation, discrete cosine transform, and quantization, the all-zero and zero-motion detection algorithms are suggested to reduce the computation of motion estimation. Simulation results show that many unnecessary computations in motion estimation are greatly reduced. For the Akiyo sequence, the proposed algorithms reduce the average numbers of search points from 28.90 and 4.99 to 2.89 and 1.40 for three-step search and diamond-search algorithms, respectively. View full abstract»

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  • An efficient spatial prediction-based image compression scheme

    Publication Year: 2002 , Page(s): 850 - 856
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1678 KB)  

    We have designed a spatial prediction-based image-compression scheme. The proposed scheme consists of two phases: the prediction phase and the quantization phase. In the prediction phase, a hierarchical structure among pixels in the image is built. Following the constructed hierarchical structure, the neighboring pixels are utilized to predict every central pixel. The prediction scheme generates an image map which indicates the prediction errors. The structure of the resulting image map is very similar to the result of a discrete wavelet transform. Thus, most quantization methods of wavelet or subband image-compression algorithms can be followed in our scheme directly to yield good compression performance. In the quantization phase, we design a multilevel threshold scheme to further enhance the result of SPIHT by taking the significance of the pixel values and the hierarchical levels into account. Furthermore, the proposed scheme can be realized by only a few integer additions and bit shifts. Simulation results indicate that the visual quality of the designed efficient spatial prediction-based image compression scheme is competitive with JPEG. All the above features make the designed image-compression scheme beneficial to the applications of real-time and wireless transmission in low-computational power environments. View full abstract»

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  • Optimizing channel allocation in a unified video-on-demand system

    Publication Year: 2002 , Page(s): 921 - 933
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (603 KB) |  | HTML iconHTML  

    Unified video-on-demand (UVoD) is an architecture that integrates multicast transmission with unicast transmission to improve system efficiency. Streaming channels in a UVoD system are divided into unicast and multicast channels, with the multicast channels further divided equally among all videos. This uniform channel-allocation scheme is simple to design and implement, but the performance may not be optimal due to differences in video popularity. This paper investigates this channel-allocation problem with the goal of optimizing system efficiency. First, the uniform allocation assumption is removed and the channel-allocation problem formulated as a nonlinear integer optimization problem. This optimization model results in nonuniform channel allocations that can save up to 10% of channels. Second, to reduce the computational complexity in solving the nonlinear optimization model, an approximate model is derived and solved under small-latency conditions to obtain a closed-form solution. Third, a much simpler class-based popularity model is proposed and shown to achieve good efficiency, even if the precise popularity of each video is not known. Lastly, a zero-multicast channel-optimization algorithm is introduced that can further reduce channel requirement for systems with a large number of video selections. Numerical results show that optimized nonuniform channel-allocation policies can achieve channel reduction over uniform channel allocation by as much as 50% for a 1000-video system. View full abstract»

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  • Blocking artifact detection and reduction in compressed data

    Publication Year: 2002 , Page(s): 877 - 890
    Cited by:  Papers (36)  |  Patents (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1526 KB)  

    A novel frequency-domain technique for image blocking artifact detection and reduction is presented. The algorithm first detects the regions of the image which present visible blocking artifacts. This detection is performed in the frequency domain and uses the estimated relative quantization error calculated when the discrete cosine transform (DCT) coefficients are modeled by a Laplacian probability function. Then, for each block affected by blocking artifacts, its DC and AC coefficients are recalculated for artifact reduction. To achieve this, a closed-form representation of the optimal correction of the DCT coefficients is produced by minimizing a novel enhanced form of the mean squared difference of slope for every frequency separately. This correction of each DCT coefficient depends on the eight neighboring coefficients in the subband-like representation of the DCT transform and is constrained by the quantization upper and lower bound. Experimental results illustrating the performance of the proposed method are presented and evaluated. View full abstract»

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  • Highly efficient predictive zonal algorithms for fast block-matching motion estimation

    Publication Year: 2002 , Page(s): 934 - 947
    Cited by:  Papers (82)  |  Patents (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1583 KB)  

    Motion estimation (ME) is an important part of any video encoding system since it could significantly affect the output quality of an encoded sequence. Unfortunately, this feature requires a significant part of the encoding time especially when using the straightforward full search (FS) algorithm. We propose two techniques, the generalized motion vector (MV) predictor and the adaptive threshold calculation, that can be used to significantly improve the performance of many existing fast ME algorithms. In particular, we apply them to create two new algorithms, named advanced predictive diamond zonal search and predictive MV field adaptive search technique, respectively, which can considerably reduce, if not essentially remove, the computational cost of ME at the encoder, while at the same time give similar, and in many cases better, visual quality with the brute force full search algorithm. The proposed algorithms mainly rely upon very robust and reliable predictive techniques and early termination criteria with parameters adapted to the local characteristics combined with the zonal based patterns. Our experiments verify the considerable superiority of the proposed algorithms versus the performance of possibly all other known fast algorithms, and FS. View full abstract»

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  • A family of wavelet-based stereo image coders

    Publication Year: 2002 , Page(s): 898 - 903
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (614 KB) |  | HTML iconHTML  

    We propose novel algorithms for stereoscopic image coding based on the hierarchical decomposition of stereo information. The proposed schemes, based on the wavelet transform and zerotree quantization, are endowed with excellent progressive transmission capability and retain the option for perfect reconstruction of the original image pair. Experimental evaluation shows that the resulting methods produce superior results when compared with other algorithms for stereo image coding. This is achieved without introducing blocking artifacts and with the valuable additional convenience of the production of embedded bitstreams. 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