The latest medium to gain attention in Europe's digitalvideo Broadcasting project is the Multipoint Microwave Distribution System, sometimes also known as Multichannel video Distribution System. Analogue MMDS ser...
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The latest medium to gain attention in Europe's digitalvideo Broadcasting project is the Multipoint Microwave Distribution System, sometimes also known as Multichannel video Distribution System. Analogue MMDS services already exist in some countries. This paper discusses the regulatory and commercial issues, spectrum planning issues and channel coding.
Wireless cable, including MMDS, ITFS, and MDS, is a terrestrial television broadcast service at 2.1 and 2.5 to 2.7 GHz. A total of 33 channels are available, each 6 MHz wide. By utilizing MPEG2 videocompression and s...
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ISBN:
(纸本)0818675853
Wireless cable, including MMDS, ITFS, and MDS, is a terrestrial television broadcast service at 2.1 and 2.5 to 2.7 GHz. A total of 33 channels are available, each 6 MHz wide. By utilizing MPEG2 videocompression and spectrally efficient digital modulation, the number of programs delivered in this bandwidth can be dramatically increased. This paper describes the method by which the programming increase is achieved. The resulting increase in spectral efficiency does come at the cost of increased stringency in transmitter specifications. This paper describes the new digital MMDS transmitter specifications and the recently developed technology that allows these tighter specifications to be met.
The goal of the MOVIE VLSI chip is to facilitate the development of software-only solutions for real time video processing applications. This chip can be seen as a building block for SIMD arrays of processing elements...
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ISBN:
(纸本)0819420425
The goal of the MOVIE VLSI chip is to facilitate the development of software-only solutions for real time video processing applications. This chip can be seen as a building block for SIMD arrays of processing elements and its architecture has been designed so as to facilitate high level language programming. The basic architecture building block associates a sub-array of computational processors with a I/O processor. A module can be seen as a small linear, systolic-like array of processing elements, connected at each end to the I/O processor. The module can communicate with its two nearest neighbors via two communication ports. The chip architecture also includes three 16-bit video ports. One important aspect in the programming environment is the C-stolic programming language. C-stolic is a C-like language augmented with parallel constructs which allow to differentiate between the array controller variables (scalar variables) and the local variables in the array structure (systolic variables). A statement operating on systolic variables implies a simultaneous execution on all the cells of the structure. Implementation examples of MOVIE-based architectures dealing with videocompressionalgorithms are given.
This paper presents an object-based, object-scalable mesh design and tracking algorithm for very low bitrate video coding, which consists of three stages: object segmentation, object boundary coding, and 2D mesh desig...
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ISBN:
(纸本)0819420425
This paper presents an object-based, object-scalable mesh design and tracking algorithm for very low bitrate video coding, which consists of three stages: object segmentation, object boundary coding, and 2D mesh design and tracking within each object. Here, we use pre-segmented test sequences;hence, object/motion segmentation is not treated. The boundary of each individual object is approximated by a polygon. Next, a node point selection algorithm followed by constrained Delauney triangulation is employed, where line segments representing the boundary of the object polygons from the constraints.
Two prevalent approaches for video coding are hybrid motion compensated DCT coding (MC/DCT) and subband coding. Hybrid MC/DCT coding has been adopted in present standards for low bit rate digitalvideocompression suc...
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ISBN:
(纸本)0819423564
Two prevalent approaches for video coding are hybrid motion compensated DCT coding (MC/DCT) and subband coding. Hybrid MC/DCT coding has been adopted in present standards for low bit rate digitalvideocompression such as ITU-T Recommendations H.261 and H.263. One problem with hybrid MC/DCT coding is that blocking artifacts in the reconstructed video sequences are prominent at low bit rates due to block segmentation of the image. Unlike block transform coding, subband coding does not suffer from these 'blocking' effects. A significant issue for the subband video coder is to fully exploit the temporal redundancy prevailing in video images for efficient video coding. More recent studies have addressed this problem using the three- dimensional (3-D) subband framework. In this study, a packet wavelet processing scheme is implemented to exploit temporal redundancy in video sequences. A bit allocation strategy is proposed and applied to the coding of the temporal subbands performed in an embedded fashion. The coding performance of the resulting 3-D wavelet subband video coder is compared with the H.261 coder at a bit rate of 384 kbps and CIF resolution, and with the H.263 coder at 64 kbps and QCIF resolution. Test sequences are selected to cover a reasonable range of scene contents.
The Virtual Studio concept replaces real background sets with computer-generated synthetic scenes. Image sequences combine real foreground action, shot in the studio, with computer generated backgrounds. The Mona Lisa...
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The Virtual Studio concept replaces real background sets with computer-generated synthetic scenes. Image sequences combine real foreground action, shot in the studio, with computer generated backgrounds. The Mona Lisa project seeks to develop and integrate technologies (algorithms, software, and hardware) needed to construct, handle, and render 3D models in real time.
Wavelet transform has been proven to be a valuable tool for image and video coding applications. Recently, a multiresolution motion estimation (MRME) technique has been proposed for wavelet-based videocompression. Th...
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ISBN:
(纸本)0819420425
Wavelet transform has been proven to be a valuable tool for image and video coding applications. Recently, a multiresolution motion estimation (MRME) technique has been proposed for wavelet-based videocompression. The MRME technique estimates the motion vector hierarchically from the low resolution to the high resolution wavelet subimages, thereby reducing the computational complexity. In this paper, we propose two techniques to enhance the coding performance of the baseline MRME technique. First, we propose to use an adaptive threshold to determine whether a motion vector should be sent to the receiver resulting in a reduced number of motion vectors and hence lower bit-rate. Secondly, we propose a bi-directional motion estimation technique in the wavelet transform domain. Here, we estimate the temporal flags (direction information) only for the blocks in the lowest resolution subimages and use the same information for the corresponding blocks in the higher resolution subimages. The proposed techniques provide a superior coding performance compared to MRME technique.
In this paper, an intraframe scheme for high compression of X-band radar images for ship traffic control is proposed. We used a proprietary radar simulator which generates maritime scenarios as seen by one or more rad...
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ISBN:
(纸本)0819423564
In this paper, an intraframe scheme for high compression of X-band radar images for ship traffic control is proposed. We used a proprietary radar simulator which generates maritime scenarios as seen by one or more radar sites. We propose a modified adaptive discrete cosine transform (MADCT) scheme which allows us to classify each 8 by 8 image block by means of a threshold criterion based on ac and dc activity. The strategy of transmission of the DCT coefficients, the recovering process of blocks incorrectly discarded, and the bit-allocation phase have been properly designed to fit with the particular application. Accurate experimental results, in terms of PSNR and compression ratio, prove the superiority of the novel scheme with respect to standard coding techniques.
A new transform/subband coding algorithm is proposed. Its original characteristic is that the transform operator is continuously updated during the encoding process on the base of previously decoded samples. Unlike ot...
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A new transform/subband coding algorithm is proposed. Its original characteristic is that the transform operator is continuously updated during the encoding process on the base of previously decoded samples. Unlike other content based algorithms, no data overhead is implied and the method can be easily incorporated into most image compression schemes. Simulation results demonstrate that a substantial benefit can be derived from the method in the context of still image and videocompression.
In this paper a technique for improving the image quality of block-based video coders is presented which combines the following pre- and postprocessing steps: Before the coding process, the image sharpness is enhanced...
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ISBN:
(纸本)0819423564
In this paper a technique for improving the image quality of block-based video coders is presented which combines the following pre- and postprocessing steps: Before the coding process, the image sharpness is enhanced by applying a special prefilter to the original image. By this means a possible degradation of the image sharpness by the coder is compensated. The decoder output is smoothed by a lowpass filter which reduces artifacts such as block discontinuities. Secondly, the quantization error of the frequency DCT coefficients is reduced by predicting AC coefficients based on the mean values of the neighboring image blocks. This step improves the luminance function within the blocks. While the original sequences show coarse blocking patterns, the images processed by this technique look smooth on the overall with well-preserved local edge structures. The tool supports all standardized DCT codecs, such as MPEG-1/2 or H.261/3.
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