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Circuits and Systems for Video Technology, IEEE Transactions on

Issue 7 • Date Oct 1999

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Displaying Results 1 - 15 of 15
  • Object recognition and tracking for remote video surveillance

    Page(s): 1045 - 1062
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1324 KB)  

    A system for real-time object recognition and tracking for remote video surveillance is presented. In order to meet real-time requirements, a unique feature, i.e., the statistical morphological skeleton, which achieves low computational complexity, accuracy of localization, and noise robustness has been considered for both object recognition and tracking. Recognition is obtained by comparing an analytical approximation of the skeleton function extracted from the analyzed image with that obtained from model objects stored into a database. Tracking is performed by applying an extended Kalman filter to a set of observable quantities derived from the detected skeleton and other geometric characteristics of the moving object. Several experiments are shown to illustrate the validity of the proposed method and to demonstrate its usefulness in video-based applications View full abstract»

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  • A fast rate-optimized motion estimation algorithm for low-bit-rate video coding

    Page(s): 994 - 1002
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    Motion estimation is known to be the main bottleneck in real-time encoding applications, and the search for an effective motion estimation algorithm (in terms of computational complexity and compression efficiency) has been a challenging problem for years. This paper describes a new block-matching algorithm that is much faster than the full search algorithm and occasionally even produces better rate-distortion curves than the full search algorithms. We observe that a piecewise continuous motion field reduces the bit rate for differentially encoded motion vectors. Our motion estimation algorithm exploits the spatial correlations of motion vectors effectively in the sense of producing better rate-distortion curves. Furthermore, we incorporate such correlations in a multiresolution framework to reduce the computational complexity. Simulation shows that this method is successful because of the homogeneous and reliable estimation of the displacement vectors. In nine out of our ten benchmark simulations, the performance of the full search algorithm and that of our subblock multiresolution method is about the same. In one out of our ten benchmark simulations, our method has improvement View full abstract»

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  • Robust transmission of video sequence over noisy channel using parity-check motion vector

    Page(s): 1063 - 1074
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    Motion compensation-discrete cosine transform (MC-DCT) coding is an efficient compression technique for digital video sequences. However, the compressed video signal is vulnerable to transmission errors over noisy channels. In this paper, we introduce a novel concept of parity-check motion vector (PMV) into the MC-DCT coder in order to improve its error robustness. By inserting the redundant PMVs systematically into the compressed bitstream, the proposed algorithm is capable of recovering very severe transmission errors, such as loss of an entire frame, in addition to detecting the errors effectively without requesting any information from external devices. The proposed algorithm is implemented based on the H.263 coder, and tested intensively in a realistic error prone environment. It is shown that the proposed algorithm provides much better objective and subjective performances than the conventional H.263 coder in the error prone environment View full abstract»

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  • A general AR-based technique for the generation of arbitrary gamma VBR video traffic in ATM networks

    Page(s): 1130 - 1137
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    Modeling variable-bit-rate (VBR) video source traffic is a crucial issue to evaluate the end-to-end performance of transmitting video signals over asynchronous transfer mode (ATM) networks. Difficulties in source modeling arise from the fact that VBR video source traffic usually follows a gamma distribution with high correlation among adjacent data. Many researchers adopt autoregressive (AR) models driven by a Gaussian error process to account for such correlation. The problem is: due to the closure property of the Gaussian distribution, the traffic so generated is Gaussian rather than gamma. As a remedy, some researchers directly consider gamma AR models instead. Unfortunately, the trouble arises from the fact that the closure property does not apply to gamma distributions, and thus, the linear operation performed by an AR model fails to produce gamma traffic. In this paper, we present a new technique that is capable of generating gamma-distributed traffic with arbitrary correlation while retaining the computational efficiency of Gaussian AR models. The central idea is to decompose given gamma traffic into a linear combination of a number of λ2(1) sequences, and each of these latter processes can be easily obtained from a Gaussian AR process through a simple nonlinear operation. Results based on actual video teleconference data are presented to verify the validity of the new algorithm View full abstract»

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  • Recovery of corrupted image data based on the NURBS interpolation

    Page(s): 1003 - 1008
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    This paper presents a recovery technique for the image block data corrupted by transmission losses, employing the two-dimensional non-uniform rational B-spline (NURBS) function. In our approach, the control grid points which generate the best approximated surface of the neighboring image data are obtained by an optimization technique. To recover the edge components in the corrupted block more faithfully, the edge linking algorithm is utilized for the estimation of the edge components, and the interpolation algorithms are modified to enhance the edge components. Computer simulation results show that the contents of the corrupted image block data, including the edge components, can he recovered more faithfully than the conventional algorithms View full abstract»

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  • Iterative least squares and compression based estimations for a four-parameter linear global motion model and global motion compensation

    Page(s): 1075 - 1099
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    In this paper, a four-parameter model for global motion in image sequences is proposed. The model is generalized and can accommodate global object motions besides the motions due to the camera movements. Only the pan and the zoom global motions are considered because of their relatively more frequent occurrences in real video sequences. Besides the traditional least-squares estimation scheme, two more estimation schemes based on the minimization of the motion field bit rate and the global prediction error energy are proposed. Among the three estimation schemes, the iterative least-squares estimation is observed to be the best because of the least computational complexity, accuracy of the estimated parameters, and similar performance as with the other schemes. Four global motion compensation schemes including the existing pixel-based forward compensation are proposed. It is observed that backward compensation schemes perform similarly to the corresponding forward schemes except for having one frame delay degradation. The pixel based forward compensation is observed to have the best performance. A new motion vector coding scheme is proposed which has similar performance as the two-dimensional entropy coding but needs much less computation. Using the proposed coding scheme with the pixel-based forward compensation, we obtain 61.85% savings in motion field bit rate over the conventional motion compensation for the Tennis sequence View full abstract»

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  • New fast and efficient two-step search algorithm for block motion estimation

    Page(s): 977 - 983
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    Block motion estimation using full search is computationally intensive. Previously proposed fast algorithms reduce the computation by limiting the number of searching locations. This is accomplished at the expense of less accuracy of motion estimation and gives rise to an appreciably higher mean squared error (MSE) for motion compensated images. We present a new fast and efficient search algorithm for block motion estimation that produces better quality performance and less computational time compared with a three-step search (TSS) algorithm. The proposed algorithms are based on the ideas of the dithering pattern for pixel decimation, multiple-candidate for pixel-decimation-based full search, and center-based distribution of the motion vector. From the experimental results, the proposed algorithm is superior to the TSS in both quality performance (about 0.2 dB) and computational complexity (about half) View full abstract»

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  • Low bit-rate video coding with implicit multiscale segmentation

    Page(s): 1115 - 1129
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    Discusses a multiscale segmentation based video compression algorithm aimed at very low bit-rate applications such as video teleconferencing and video phones. We introduce novel techniques for multiscale segmentation based motion compensation and residual coding. Our region based forward motion compensation strategy (in terms of direction of motion vector, which is from the previous frame to the current frame) regulates the size and number of regions used, by pruning a multiscale segmentation of video frames. Since regions used for motion compensation are obtained by segmenting the previously decoded frame, the shape of the regions need not be transmitted to the decoder. Furthermore, our hierarchical motion compensation strategy refines an initial region level, coarse motion field to obtain a dense motion field which provides pixel level motion vectors. The refinement procedure does not require any additional information to be transmitted. This motion compensation technique effectively addresses the problem of dealing with “holes” and “overlapping regions” which are inherent to forward motion compensation. Residual coding is performed using a novel method which exploits the fact that the energy of the residual resulting from motion compensation is concentrated in a priori predictable positions. We show that this residual coding technique can also be extrapolated to improve the performance of coders using a block based motion compensation strategy. A fusion of these concepts leads to a gain of 2-3 dB in peak signal-to-noise ratio, apart from significant perceptual improvement, over a generic video coding algorithm using a block based motion compensation strategy (such as H.261 or H.263) for a variety of test sequences View full abstract»

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  • Subband dictionaries for low-cost matching pursuits of video residues

    Page(s): 984 - 993
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    “Matching pursuits” is a signal expansion technique whose efficiency for video coding has already been largely demonstrated in the MPEG-4 framework. In this paper, our attention focuses on complexity issues. First, the most expensive step of the signal expansion process is significantly speeded up by exploiting results achieved in the wavelet and multiresolution theory. A subband dictionary is proposed as an alternative to the Gabor dictionary that has been used up to now. Equivalent levels of quality are achieved with both dictionaries, but the computational cost is significantly reduced when using the subband one. Then, we explain how, with any dictionary, the linearity of the inner product could be exploited to further speed up the process in return for an increased amount of memory View full abstract»

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  • Fast extraction of spatially reduced image sequences from MPEG-2 compressed video

    Page(s): 1100 - 1114
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    MPEG-2 video standards are targeted for high-quality video broadcast and distribution and are optimized for efficient storage and transmission. However, it is difficult to process MPEG-2 for video browsing and database applications without first decompressing the video. Yeo and Liu (1995) have proposed fast algorithms for the direct extraction of spatially reduced images from MPEG-1 video. Reduced images have been demonstrated to be effective for shot detection, shot browsing and editing, and temporal processing of video for video presentation and content annotation. In this paper, we develop new tools to handle the extra complexity in MPEG-2 video for extracting spatially reduced images. In particular, we propose new classes of discrete cosine transform (DCT) domain and DCT inverse motion compensation operations for handling the interlaced modes in the different frame types of MPEG-2, and we design new and efficient algorithms for generating spatially reduced images of an MPEG-2 video. The algorithms proposed in this paper are fundamental for efficient and effective processing of MPEG-2 video View full abstract»

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  • Adaptive motion tracking block matching algorithms for video coding

    Page(s): 1025 - 1029
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    In most block-based video coding systems, the fast block matching algorithms (BMAs) use the origin as the initial search center, which may not track the motion very well. To improve the accuracy of the fast BMAs, a new adaptive motion tracking search algorithm is proposed. Based on the spatial correlation of motion blocks, a predicted starting search point, which reflects the motion trend of the current block, is adaptively chosen. This predicted search center is found closer to the global minimum, and thus the center-biased BMAs can be used to find the motion vector more efficiently. Experimental results show that the proposed algorithm enhances the accuracy of the fast center-biased BMAs, such as the new three-step search, the four-step search, and the block-based gradient descent search, as well as reduces their computational requirement View full abstract»

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  • Correction of intensity flicker in old film sequences

    Page(s): 1013 - 1019
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    Temporal intensity flicker is a common artifact in old film sequences. Removing disturbing temporal fluctuations in image intensities is desirable because it increases both the subjective quality and, where image sequences are stored in a compressed format, the coding efficiency. We describe a robust technique that corrects intensity flicker automatically by equalizing local frame means and variances in the temporal sense. The low complexity of our method makes it suitable for hardware implementation. We tested the proposed method on sequences with artificially added intensity flicker and on original film material. The results show a great improvement View full abstract»

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  • A unified approach to shot change detection and camera motion characterization

    Page(s): 1030 - 1044
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    This paper describes an original approach to partitioning of a video document into shots. Instead of an interframe similarity measure which is directly intensity based, we exploit image motion information, which is generally more intrinsic to the video structure itself. The proposed scheme aims at detecting all types of transitions between shots using a single technique and the same parameter set, rather than a set of dedicated methods. The proposed shot change detection method is related to the computation, at each time instant, of the dominant image motion represented by a two-dimensional affine model. More precisely, we analyze the temporal evolution of the size of the support associated to the estimated dominant motion. Besides, the computation of the global motion model supplies by-products, such as qualitative camera motion description, which we describe in this paper, and other possible extensions, such as mosaicing and mobile zone detection. Results on videos of various content types are reported and validate the proposed approach View full abstract»

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  • Modified one-bit transform for motion estimation

    Page(s): 1020 - 1024
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    Motion estimation using the one-bit transform (1BT) was proposed by Natarajan, Bhaskaran and Konstantinides (see ibid., vol.7, p.702-06, 1997) to achieve large computation reduction. However, it degrades the predicted image by almost 1 dB as compared with full search. We propose a modification to the 1BT by adding conditional local searches. Simulation results show that the proposed modification improves the peak signal-to-noise ratio (PSNR) significantly at the expense of slightly increased computational complexity. A variant of the proposed modification called the multiple-candidate two-step search (M2SSFS) is found to be particularly good for high quality, high bit rate video coding. In the MPEG-1 simulation, its PSNR is within 0.1 dB from that of full search at bit rates higher than 1 Mbit/s with a computation reduction factor of ten View full abstract»

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  • Comparison of techniques for intra-frame coding of arbitrarily shaped video object boundary blocks

    Page(s): 1009 - 1012
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    This paper presents experimental results that demonstrate that the weakly separable polynomial orthonormal transform outperforms the shape adaptive discrete cosine transform (SADCT) and the previously introduced improved SADCT with ΔDC correction at the expense of a nonprohibitive increase in the number of computations. Some other improvements to SADCT-like schemes are also suggested 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