By Topic

Circuits and Systems for Video Technology, IEEE Transactions on

Issue 5 • Date May 2003

Filter Results

Displaying Results 1 - 10 of 10
  • Efficient background video coding with static sprite generation and arbitrary-shape spatial prediction techniques

    Publication Year: 2003 , Page(s): 394 - 405
    Cited by:  Papers (11)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (925 KB)  

    An efficient static sprite-generation and compression scheme is proposed for background video coding. First, considering both short- and long-term motion influences, a hybrid technique is proposed in the sprite generation to search the background motion relative to the generated sprite image. In order to prevent the sprite image from being blurred due to the inaccurate segmentation, a reliability-based blending technique is developed. Both the background video at every frame and the sprite image are categorized into reliable, unreliable, and undefined regions. Each region uses a unique strategy in blending. This makes the proposed technique work well even in the case of coarse segmentation. Second, an arbitrary-shape spatial prediction technique is proposed to efficiently compress the sprite image. Due to the property of the background video object, the sprite image often contains many flat and texture-correlation regions. Therefore, utilizing directional spatial prediction can significantly improve the efficiency of sprite coding. In general, the generated sprite is not a rectangular image. Since traditional spatial-prediction methods have difficulty in handling those contour blocks, a padding technique derived from rate-distortion optimization is proposed. Experimental results show that the proposed scheme can generate the background sprite image with better visual quality. Compared with the MPEG-4 sprite-coding scheme, it can also significantly improve the coding efficiency up to 3.0 dB at low bit rates. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • MPEG-4 one-pass VBR rate control for digital storage

    Publication Year: 2003 , Page(s): 447 - 452
    Cited by:  Papers (12)  |  Patents (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (319 KB) |  | HTML iconHTML  

    One-pass, variable bit-rate (VBR) rate control is ideally suited to the requirements of real-time video encoding for the purpose of digital storage. Previous MPEG one-pass VBR rate control algorithms have been based on appropriate selection of quantization scale parameters for controlling the bit rate and quality of the output bitstream. The major disadvantage of relying solely on quantization scales, for rate control, is the introduction of significant perceptual distortion when high quantization scales are used. We propose an MPEG-4, 1-pass, VBR rate control scheme that relies on the selective use of the MPEG-4 reduced resolution mode to supplement modulation of the quantization scale and provide an effective rate control strategy. Experimental results show that the proposed algorithm can encode high-complexity, standard definition (720 × 480) video sequences at rates as low as 750 kbps without incurring significant perceptual artifacts. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Genetic algorithm optimization of multidimensional grayscale soft morphological filters with applications in film archive restoration

    Publication Year: 2003 , Page(s): 406 - 416
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (934 KB)  

    Automatic restoration of old film archives has become of increasing interest in the last few years with the rise of consumer digital video applications and the need to supply more programming material of an acceptable quality in a multimedia context. A technique is described for the optimization of multidimensional grayscale soft morphological filters for applications in automatic film archive restoration, specific to the problem of film dirt removal. The optimization is undertaken with respect to a criterion based on mean absolute error and is performed using a genetic algorithm. Experiments have shown that the filter found using this technique has excellent performance in attenuating/removing film dirt from image sequences and has little, if any, effect on the image detail. The results of applying such a filter to a real image sequence were analyzed and compared to those obtained by restoring the same image sequence using a global filtering approach (LUM filter) and a spatio-temporal local filtering approach (ML3Dex filter with noise detection). From a film dirt removal point of view, the optimized soft morphological filter showed improved results compared to the LUM filter and comparable results with respect to the ML3Dex filter with noise detection. Also, the optimized filter accurately restored all fast-moving objects present in the sequence, without the need for motion compensation, whereas the other two methods failed to do this. The proposed method proved to be a simple, fast, and cheap approach for the automatic restoration of old film archives. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Predictive watershed: a fast watershed algorithm for video segmentation

    Publication Year: 2003 , Page(s): 453 - 461
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1149 KB)  

    The watershed transform is a key operator in video segmentation algorithms. However, the computation load of watershed transform is too large for real-time applications. In this paper, a new fast watershed algorithm, named P-watershed, for image sequence segmentation is proposed. By utilizing the temporal coherence property of the video signal, this algorithm updates watersheds instead of searching watersheds in every frame, which can avoid a lot of redundant computation. The watershed process can be accelerated, and the segmentation results are almost the same as those of conventional algorithms. Moreover, an intra-inter watershed scheme (IP-watershed) is also proposed to further improve the results. Experimental results show that this algorithm can save 20%-50% computation without degrading the segmentation results. This algorithm can be combined with any video segmentation algorithm to give more precise segmentation results. An example is also shown by combining a background registration and change-detection-based segmentation algorithm with P-Watershed. This new video segmentation algorithm can give accurate object masks with acceptable computation complexity. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Improved single-video-object rate control for MPEG-4

    Publication Year: 2003 , Page(s): 385 - 393
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1064 KB)  

    Rate control plays a central role in constant bit-rate video coding applications using MPEG-4. This paper considers single-video-object rate control for MPEG-4 and presents a new rate-control algorithm based on the quadratic rate-distortion (R-D) model. The major innovations are a novel constraint for the least-mean-square estimation of the model parameters of the R-D function, a new measure for the encoding complexity, novel quantizer control and an efficient frame skipping strategy. Simulation results show that the MPEG-4 coder, using the proposed algorithm, can achieve a higher PSNR than a coder using the conventional rate-control algorithm. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive rate control using nonlinear regression

    Publication Year: 2003 , Page(s): 432 - 439
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (691 KB) |  | HTML iconHTML  

    This paper presents a simple, fast, and accurate rate-control algorithm using nonlinear regression that plays a central role in estimation theory. We measure a conditional mean by estimating a joint probability density function (PDF) using Parzen's (1962) window. The training data pick up the nonlinear rate-distortion (R-D) relationship between the quantization parameter (QP) and the bits spent for each macroblock depending on the sum of absolute differences (SAD). We increase the accuracy of this joint PDF by clustering the training data depending on the QP values within admissible ranges. This localization helps understand image characteristics more accurately. Then we apply the adaptive vector quantization (AVQ) to simplify the conditional mean estimation of the rate given the SAD and QP values. This information is stored into three look-up tables. They contain the localized R-D function on macroblock basis. We use these tables to find the optimal QP values in least-mean-square sense for a given bit budget of the current frame. Simulation results show that the proposed algorithm outperforms the informative MPEG-4 rate-control algorithm in terms of reproduced image quality and coding efficiency. Our algorithm gives better image quality using much fewer bits. Most of all, it keeps the bit rate very accurately due to the accuracy of the conditional mean estimator that solves the nonlinear R-D function. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive postprocessors with DCT-based block classifications

    Publication Year: 2003 , Page(s): 365 - 375
    Cited by:  Papers (9)  |  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1331 KB) |  | HTML iconHTML  

    In this paper, an adaptive postprocessor figured with discrete cosine transform (DCT)-based block classification to effectively remove the so-called blocky effect from compressed video sequences is proposed. The proposed DCT-based detection algorithms for both intraframes and interframes require much lower computation complexity than the spatial-domain approaches. In order to preserve the edge information, the adaptive postprocessor is also designed with a DCT-based edge detection mechanism such that a one-dimensional median filter can be adaptively adjusted to match with the edge orientation. Simulation results show that the proposed DCT-based detection algorithms accurately classifies smooth, edge, or nonsmooth blocks to help the adaptive postprocessor to effectively remove the blocky effect and sharply preserve the edge information. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A study of MPEG-4 rate control scheme and its improvements

    Publication Year: 2003 , Page(s): 440 - 446
    Cited by:  Papers (33)  |  Patents (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB) |  | HTML iconHTML  

    This paper discusses some practical issues in implementing the MPEG-4 Q2 rate-control scheme, and proposes a number of ways to improve it. The improved algorithm has the following main features: (1) the bits allocated to each P-frame or B-frame are in proportion to its distance from the end this GOP. i.e., more bits are allocated to the frames that are nearer to their reference I-frame; (2) the target buffer level is a function of the frame position in the GOP, so that it will be achieved gracefully at the end of a GOP; and (3) the quantization value of an I-frame is decided based on its spatial complexity. Experimental results show that the improved rate-control scheme has significantly reduced the occurrence of frame skipping, increased the average PSNR by up to 0.6 dB, and improved the perceptual quality of the reconstructed video. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A statistical adaptive block-matching motion estimation

    Publication Year: 2003 , Page(s): 417 - 431
    Cited by:  Papers (7)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1731 KB)  

    We address the problem of motion estimation (ME) in digital video sequences and propose a new fast, adaptive, and efficient block-matching algorithm. Higher quality and efficiency are achieved using a statistical model for the motion vectors. This model introduces adaptation in the search window, drastically reducing the number of positions where correlation-type computation is performed. The efficiency is further improved by progressively undersampling the macroblock. Patterns for undersampling are proposed to obtain the maximum benefit from single instruction multiple data (SIMD) instructions. In contrast with existing motion-estimation techniques, search strategy and subsampled patterns are closely linked. This shows that a good search strategy is much more important than blindly reducing the number of pixels considered for the matching pattern. We describe an implementation of the proposed matching strategy that exploits the very long instruction word (VLIW) and SIMD technology available in the new Itanium processor family. Results show that the proposed algorithm adapts easily to the evolution of the scene avoiding annoying quality drops that can be observed with other deterministic algorithms. The total number of operations required by the proposed method is inferior to those required by traditional approaches. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Scalable portrait video for mobile video communication

    Publication Year: 2003 , Page(s): 376 - 384
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1048 KB)  

    Wireless networks have been rapidly developing in recent years. General Packet Radio Service (GPRS) and Code Division Multiple Access (CDMA 1X) for wide areas, and 802.11 and Bluetooth for local areas have already emerged. Broadband wireless networks urgently call for rich contents for consumers. Among various possible applications, video communication is one of the most promising for mobile devices on wireless networks. This paper describes the generation, coding, and transmission of an effective video form, scalable portrait video for mobile video communication. As an expansion to bilevel video, portrait video is composed of more gray levels, and therefore possesses higher visual quality while it maintains a low bit rate and low computational costs. Portrait video is a scalable video in that each video with a higher level always contains all the information of the video with a lower level. The bandwidths of 2-4-level portrait videos fit into the bandwidth range of 20-40 kbps that GPRS and CDMA 1X can stably provide; therefore, portrait video is very promising for video broadcast and communication on 2.5-G wireless networks. With portrait video technology, we are the first to enable two-way video communication on pocket PCs and handheld PCs. 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