By Topic

Circuits and Systems for Video Technology, IEEE Transactions on

Issue 5 • Date May 2001

Filter Results

Displaying Results 1 - 11 of 11
  • Efficient connected-index finite-length arithmetic codes

    Page(s): 581 - 593
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    In this paper, we propose a connected-index approach to construct efficient finite-length arithmetic codes by splitting the information of the last nonfitting symbol into the current and subsequent codewords. The proposed arithmetic codes, which limit the error propagation in about one block, require neither a post-appended end-of-block symbol, nor pre-affixed side-information, to characterize the number of encoded symbols. Hence, the proposed finite-length arithmetic codes can nearly achieve the coding efficiency attained by infinite-length arithmetic codes. With high coding efficiency, limited error-propagation, and the regular process, the proposed coding approach is suitable for information exchange with small packets in modern high-speed network systems View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design of wavelet-based image codec in memory-constrained environment

    Page(s): 642 - 650
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (228 KB)  

    This work presents a high-performance wavelet transform based image coder that is designed for image compression in a system with limited resources. In this image coder, the dual-sliding wavelet transform (DSWT) is first applied to the image data to generate wavelet coefficients in fixed-size blocks. Here, a block consists of wavelet coefficients only from a single subband. Then, the resulting coefficient blocks are directly coded with the low-complexity binary description (LCBiD) coefficient coding algorithm. No parent-child relationship is exploited in the coding process. There is no intermediate buffering needed between DSWT and LCBiD. The compressed bit stream generated by the proposed coder is both SNR and resolution scalable, as well as highly resilient to transmission errors. Both DSWT and LCBiD process the data in blocks whose size is independent of the size of the input image. This gives more flexibility in its implementation. The codec has a very good coding performance even the size of a coefficient block is as small as (16,16) View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Semantic video object extraction using four-band watershed and partition lattice operators

    Page(s): 603 - 618
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (472 KB)  

    We conceive the problem of multiple semantic video object (SVO) extraction as an issue of designing extensive operators on a complete lattice of partitions. As a result, we propose a framework based on spatial partition generation and application of optimal operators on the generated partitions. Based on a statistical analysis of the watershed algorithm, we develop a multivalued morphological spatial segmentation method that incorporates an edge-driven marker extraction algorithm and a growing method which integrates both color and edge information. Having embedded the problem in the partition lattice framework, we propose a spatio-temporal regional maximum likelihood operator for extraction purposes. Some theoretical properties of the operator are established. Experimental results on several MPEG-4 test video sequences show that our scheme improves the precision of the extracted SVO boundaries compared to traditional watershed algorithms and provides accurate tracking of multiple SVOs in both static and moving camera scenarios. Furthermore, this scheme can be extended to deal with more general interactive video authoring systems View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Lifting factorization-based discrete wavelet transform architecture design

    Page(s): 651 - 657
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    In this paper, two new system architectures, overlap-state sequential and split-and-merge parallel, are proposed based on a novel boundary postprocessing technique for the computation of the discrete wavelet transform (DWT). The basic idea is to introduce multilevel partial computations for samples near data boundaries based on a finite state machine model of the DWT derived from the lifting scheme. The key observation is that these partially computed (lifted) results can also be stored back to their original locations and the transform can be continued anytime later as long as these partial computed results are preserved. It is shown that such an extension of the in-place calculation feature of the original lifting algorithm greatly helps to reduce the extra buffer and communication overheads, in sequential and parallel system implementations, respectively. Performance analysis and experimental results show that, for the Daubechies (see J.Fourier Anal. Appl., vol.4, no.3, p.247-69, 1998) (9,7) wavelet filters, using the proposed boundary postprocessing technique, the minimal required buffer size in the line-based sequential DWT algorithm is 40% less than the best available approach. In the parallel DWT algorithm we show 30% faster performance than existing approaches View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A fast multiresolution feature matching algorithm for exhaustive search in large image databases

    Page(s): 673 - 678
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    Most of the content-based image retrieval systems require a distance computation for each candidate image in the database. As a brute-force approach, the exhaustive search can be employed for this computation. However, this exhaustive search is time-consuming and limits the usefulness of such systems. Thus, there is a growing demand for a fast algorithm which provides the same retrieval results as the exhaustive search. We propose a fast search algorithm based on a multiresolution data structure. The proposed algorithm computes the lower bound of distance at each level and compares it with the latest minimum distance, starting from the low-resolution level. Once it is larger than the latest minimum distance, we can remove the candidates without calculating the full-resolution distance. By doing this, we can dramatically reduce the total computational complexity. It is noticeable that the proposed fast algorithm provides not only the same retrieval results as the exhaustive search, but also a faster searching ability than existing fast algorithms. For additional performance improvement, we can easily combine the proposed algorithm with existing tree-based algorithms. The algorithm can also be used for the fast matching of various features such as luminance histograms, edge histograms, and local binary partition textures View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive postfiltering of transform coefficients for the reduction of blocking artifacts

    Page(s): 594 - 602
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    This paper proposes a novel postprocessing technique for reducing blocking artifacts in low-bit-rate transform-coded images. The proposed approach works in the transform domain to alleviate the accuracy loss of transform coefficients, which is introduced by the quantization process. The masking effect in the human visual system (HVS) is considered, and an adaptive weighting mechanism is then integrated into the postfiltering. In low-activity areas, since blocking artifacts appear to be perceptually more detectable, a large window is used to efficiently smooth out the artifacts. In order to preserve image details, a small mask, as well as a large central weight, is employed for processing those high-activity blocks, where blocking artifacts are less noticeable due to the masking ability of local background. The quantization constraint is finally applied to the postfiltered coefficients. Experimental results show that the proposed technique provides satisfactory performance as compared to other postfilters in both objective and subjective image quality View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Motion-compensated layered video coding for playback scalability

    Page(s): 619 - 628
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    We propose a multilayered video coding scheme based on motion estimation which enables a decoder to dynamically change its temporal and spatial resolution during playback. In the proposed scheme, a new motion-prediction structure with a temporal hierarchy of frames is adopted to afford temporal resolution scalability and the wavelet decomposition with a new intra-update algorithm is used to offer spatial scalability. Experimental results show that the proposed scheme exhibits a higher compression ratio than conditional replenishment schemes because it further reduces the temporal redundancy using motion estimation. Also the proposed intra-update technique enables adaptation to dynamic change of spatial resolution with the effective follow-up of prediction in the decoder while preventing the large peaks in bit rate. Therefore, the proposed scheme is expected to be effectively used in heterogeneous environments such as the Internet, ATM, and wireless networks where dynamic scalability and interoperability are required View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A rate-control scheme for video transport over wireless channels

    Page(s): 569 - 580
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    We investigate the scenario of using the automatic repeat request (ARQ) retransmission scheme for two-way video communications over wireless Rayleigh fading channels. Video quality is the major concern of these applications. We show that, during the retransmissions of error packets, due to the reduced channel throughput, the video encoder buffer may fill-up quickly and cause the TMN8 rate-control algorithm to significantly reduce the bits allocated to each video frame. This results in PSNR degradation and many skipped frames. To minimize the number of frames skipped, we propose improved rate-control schemes that take into consideration the effects of the video buffer fill-up, an a priori channel model, and the channel feedback information. We also show that a discrete cosine transform (DCT) coefficient soft-thresholding scheme can be applied to further improve video quality. As a result, our proposed rate-control schemes encode the video sequences with less frame skipping and with higher PSNR compared to TMN8 View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A replenishment technique for low bit-rate video compression based on wavelets and vector quantization

    Page(s): 658 - 663
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (96 KB)  

    This paper presents a variable bit-rate encoding scheme developed for digital video compression based on spatiotemporal decomposition and vector quantization. This encoding scheme exploits the interframe redundancy present in image sequences by employing replenishment of code-vector labels. The experiments indicated that code-vector label replenishment results in a significant reduction of the number of bits required for encoding the frames of image sequences. The proposed video-compression system outperformed the H.261 video-compression standard at high compression ratios, and produced reconstructed video of comparable visual quality at medium and low compression ratios View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance evaluation of 32 kbits/s real-time and dual-direction video communication system for wireless channels

    Page(s): 664 - 672
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    This paper describes the construction and performance evaluation of a mobile video communication system composed of an H.263 video encoder, decoder, and RF transceiver equipment. It can establish a video connection using a 32 kbits/s wireless channel because it uses automatic repeat request (ARQ) as the error control scheme. Retransmission control can produce excessive transmission delay, but the improved ARQ protocol and coding-rate control scheme adopted by this system minimizes the delay. This ARQ protocol uses short ARQ frame length and an acknowledgement/negative acknowledgement (ACK/NAK) indicator. The coding-rate control scheme uses backward NAK signals to reduce the coding rate of the video encoder as necessary. We measure the transmission delay characteristics of this video system and confirm that the proposed scheme can reduce the delay over a noisy channel. Subjective assessment tests involving videophone usage are also conducted. Test results show that in a noisy channel (BER=3×10-3), this system can achieve the same mean opinion store as in a noiseless channel View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Image sequence segmentation using 3-D structure tensor and curve evolution

    Page(s): 629 - 641
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (292 KB)  

    We describe a novel approach for image sequence segmentation. It contains three parts: global motion compensation, robust frame differencing, and curve evolution. It is computationally efficient, does not require dense-field motion estimation, and is insensitive to noise and global/background motion. It works for black-and-white and color image sequences. The efficacy of this approach is demonstrated on both TV and surveillance image sequences View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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