So far, the problems of separating and recognizing the objects hom overlapped image have been discussed horn various points of view. For example, in industrial applications like bin-picking and selection of tools from...
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The vector quantization scheme has proven to be very effective in image coding. One of the most important steps in the whole process is the design of the codebook. The codebook is generally designed using the Linde-Bu...
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The vector quantization scheme has proven to be very effective in image coding. One of the most important steps in the whole process is the design of the codebook. The codebook is generally designed using the Linde-Buzo-Gray algorithm, which is in essence a clustering algorithm that uses a large training set of empirical data that are statistically representative of the image to be quantized. The problem addressed is the stochastic generation of the codebook. The approach is to model the codebook according to some previous model defined for the image to be encoded and then to generate the training set according to the same model and not according to some specific data sequence. The model used is the well-known autoregressive model. Good visual results are shown in the range of 0.5-0.8 b/pixel.< >
A subband/VQ coder that combines the three color components of each subband pixel into a length 3 vector and then vector quantizes each subband is presented. Perceptual weights derived from subjective visual experimen...
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A subband/VQ coder that combines the three color components of each subband pixel into a length 3 vector and then vector quantizes each subband is presented. Perceptual weights derived from subjective visual experiments are used along with the rate-distortion curves to determine a perceptually optimal bit allocation. Advantages of this method are that fewer codebooks need to be designed and the resulting bit allocation problem is simplified. Preliminary results show that this method achieves results comparable to the more standard subband/VQ method where the color components of each subband are vector quantized separately using the perceptually optimal bit allocation algorithm. To obtain the required compression ratio and the high color fidelity required for HDTV applications, the vector quantization is done in a perceptually uniform color space.< >
The authors describe the architecture of a real-time progressive full-search vector quantizer (VQ) suitable for VLSI implementation. Because of the large memory and ALU requirements of a single VQ, the compression is ...
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The authors describe the architecture of a real-time progressive full-search vector quantizer (VQ) suitable for VLSI implementation. Because of the large memory and ALU requirements of a single VQ, the compression is performed in stages. Each stage generates a codebook index, a difference vector, and total pixel error squared. The encoder chip is partitioned into master/slave portions dividing the codebooks and computational requirements between the two ASICs (application-specific integrated circuits). Because the system is modular, several encoder stages can be cascaded to achieve a higher-quality reconstruction. The VQ is progressive in the sense that each additional stage of encoding produces better visual quality. The authors also describe the architecture of a completion chip which can be used in conjunction with several encoders to realize a single VQ.< >
A model-based coding system has come under serious consideration for the next generation of image coding schemes, aimed at greater efficiency in TV-telephone and TV-conference systems [l]-[5]. In this model-based codi...
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ISBN:
(纸本)0819407429
A model-based coding system has come under serious consideration for the next generation of image coding schemes, aimed at greater efficiency in TV-telephone and TV-conference systems [l]-[5]. In this model-based coding system, the sender’s model image is transmitted and stored at the receiving side before the start of conversation. During the conversation, feature points are extracted from the facial image of the sender, and are transmitted to the receiver. The facial expression of the sender facial is reconstructed from the feature points received and a wireframe model constructed at the receiving side.
An audio-graphic teleconferencing system has been developed that uses ordinary personal computers (PCs) interconnected over a basic rate (2B+D) ISDN line. The system supports high-speed transmission of 200-dpi resolut...
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ISBN:
(纸本)0819407437
An audio-graphic teleconferencing system has been developed that uses ordinary personal computers (PCs) interconnected over a basic rate (2B+D) ISDN line. The system supports high-speed transmission of 200-dpi resolution documents read by an optical scanner and presented on the displays of the conference participants. While looking at the same material, the conferees can interactively converse and make handwritten notations for all the participants to see on the document via a LCD tablet. This paper describes the configuration and performance of the system, focusing mainly on the ISDN-based multi-media transmission method and the method of reducing and enlarging binary images.
This conference proceedings contains 44 papers. The topics discussed are motion estimation and motion analysis;image transmission and communication systems;3-D motion analysis;hierarchical image coding;entropy coding;...
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ISBN:
(纸本)0819407429
This conference proceedings contains 44 papers. The topics discussed are motion estimation and motion analysis;image transmission and communication systems;3-D motion analysis;hierarchical image coding;entropy coding;and visual communication hardware.
This conference proceedings contains 46 papers. The topics discussed are video sequence coding;hierarchical image decomposition;vector quantization;model based image coding;super high definition image systems;and stil...
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ISBN:
(纸本)0819407429
This conference proceedings contains 46 papers. The topics discussed are video sequence coding;hierarchical image decomposition;vector quantization;model based image coding;super high definition image systems;and still image coding.
A variable bit-rate HDTV coding algorithm based on motion-adaptive DCT is investigated for ATM environments in B-ISDN. Adaptive 2-layered coding, an ATM cell matrix for error correction, and a block interleave for err...
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ISBN:
(纸本)0819407429
A variable bit-rate HDTV coding algorithm based on motion-adaptive DCT is investigated for ATM environments in B-ISDN. Adaptive 2-layered coding, an ATM cell matrix for error correction, and a block interleave for error concealment are proposed to keep picture quality high by compensating for ATM cell loss. A new VLC and a congestion control scheme that restricts peak-rate and average-rate are also proposed for traffic control. The proposed algorithm is shown to reduce the coding bit-rate for HDTV conference applications in ATM environments to 10 - 30 Mb/s.
Two adaptive approaches for nonstationary filtering of image sequences are presented and experimentally compared. According to the first approach, a recursive spatio-temporal motion- compensated (MC) estimator is appl...
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ISBN:
(纸本)0819407437
Two adaptive approaches for nonstationary filtering of image sequences are presented and experimentally compared. According to the first approach, a recursive spatio-temporal motion- compensated (MC) estimator is applied to the noisy sequence that adapts to the local spatial and temporal signal activity. A separable 3-D estimator is proposed that consists of three coupled 1-D estimators; its input is the noisy image plus additional signals that contain spatial information provided by a simple edge-detector or temporal information provided by the MC backward difference (registration error). The steady-state gain and the parameters of this separable estimator are computed by closed form formulae, thus allowing a very efficient implementation. According to the second approach, the noisy signal is first decomposed into a stationary and a nonstationary part based on an estimate of its local mean and deviation. A minimum variance estimator of the local mean and deviation of the observed signal is used. After the current mean is subtracted from the observed signal and the signal is normalized by using the current deviation, a relatively simple noise filter is used for filtering the stationary part. The above methods are applied to the filtering of noisy video-conferenceimage sequences for various levels of noise. Both methods show a very satisfactory performance taking into consideration their simplicity and computational efficiency.
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