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.
The signal processing principles utilized in sensory neural systems such as the retina and optic lobes of insects are studied with a view to deriving principles for design of analog integrated circuit peripheral (earl...
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The signal processing principles utilized in sensory neural systems such as the retina and optic lobes of insects are studied with a view to deriving principles for design of analog integrated circuit peripheral (early) processing systems. The basic peripheral processing principles in biological visual systems are gain adaptation and lateral inhibition. The utility, both in biological and artificial neural networks, of nonlinear lateral inhibition is examined. Because lateral inhibition involves only near neighbor interactions between cells, optoelectronic implementations in the form of monolithically integrated photodetector arrays are particularly attractive. These have wide practical applicability for machine vision, optical scanning, and image enhancement purposes. Such implementations are completely analog and can be designed to require only one transistor per unilateral interconnection.< >
The authors investigate four different concepts which are candidates to resolve the hidden surface removal problem without the use of priorities. All four are based on determining a linear depth order consistent with ...
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The authors investigate four different concepts which are candidates to resolve the hidden surface removal problem without the use of priorities. All four are based on determining a linear depth order consistent with the partial order of primitives in a span. A span is a small subimage of the image being generated. The first approach examines parallel sorting of all the depth values of all primitives in a span. The second approach, for each pixel in a span, builds a list of all the primitives in that span, totally ordered by depth. These lists represent the partial order of the primitives, and are later enumerated to give a total order. The third approach performs up to k pairwise comparisons in parallel between primitives to determine if a depth relationship exists. If one exists, the pair is stored in a partial order graph which is later enumerated to create a total order. The fourth approach involves the use of a pipeline of length k, which, at any given time, contains up to k primitives which are closest. If there are more than k primitives in a span, more than one iteration is needed. The fourth approach appears to be the most promising, even though there are situations in which it generates an incorrect ordering.< >
This volume of the conference proceedings contains 55 articles pertaining to visualcommunications and imageprocessing. The papers address topics in the following subject areas: Segmentation/Classification, Texture, ...
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ISBN:
(纸本)0819404217
This volume of the conference proceedings contains 55 articles pertaining to visualcommunications and imageprocessing. The papers address topics in the following subject areas: Segmentation/Classification, Texture, image Restoration, Digital imageprocessing, JPEG/MPEG Algorithms and Implementation, Vision Science and Technology for Space, Pattern Recognition, and image Sequence Coding.
An image-sequence-coding scheme based on the extracted information of 3-D structure and motion is presented. The goal is to achieve efficient and high-quality visual telecommunications through the use of 3-D scene cha...
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An image-sequence-coding scheme based on the extracted information of 3-D structure and motion is presented. The goal is to achieve efficient and high-quality visual telecommunications through the use of 3-D scene characteristics inherent in image sequences. The structure and motion of rigid and nonrigid objects are robustly estimated from the displacement vectors between frames. As an image source model in the image-coding process, the 3-D information provides more efficient representations of image sequences because they are derived directly from the scene characteristics. Experimental results are given and suggest that the scheme can be a viable solution in realizing high-quality visualcommunications.
In this paper, a distributed detection approach for displacement estimation in image sequences is presented. This method is derived from a Bayesian framework and reduces to a M-ary Hypothesis test among a representati...
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ISBN:
(纸本)0819404217
In this paper, a distributed detection approach for displacement estimation in image sequences is presented. This method is derived from a Bayesian framework and reduces to a M-ary Hypothesis test among a representative set of possible displacement vectors. It is shown that the mean-squared error based block-matching (BM) algorithm is a special case of this general approach. In our approach, at each point of the current frame a set of overlapping localized detectors outputs a number of estimates for the displacement vector. Then, a distributed detection network is adopted for the fusion of the these estimates. Since the computational load is high, suboptimal but computationally efficient solutions are proposed. The above method gives a more accurate estimation of the displacement field and it is shown to be more robust in the presence of occlusion and noise, compared to the BM algorithm. Experimental results on video-conferenceimage sequences are presented.
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