In current interframe video compression systems, the encoder performs predictive coding to exploit the similarities of successive frames. The Wyner-Ziv theorem on source coding with side information available only at ...
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In current interframe video compression systems, the encoder performs predictive coding to exploit the similarities of successive frames. The Wyner-Ziv theorem on source coding with side information available only at the decoder suggests that an asymmetric video codec, where individual frames are encoded separately, but decoded conditionally (given temporally adjacent frames) could achieve similar efficiency. We report the first results on a Wyner-Ziv coding scheme for motion video that uses intraframe encoding, but interframe decoding.
The problem of sequentially scanning and predicting data arranged in a multi-dimensional array is considered. We introduce the notion of a scandictor, which is any scheme for the sequential scanning and prediction of ...
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The problem of sequentially scanning and predicting data arranged in a multi-dimensional array is considered. We introduce the notion of a scandictor, which is any scheme for the sequential scanning and prediction of such data. The scandictability of a probabilistic data-array is defined as the best achievable expected "scandiction" performance on that array. We derive a lower bound on scandiction performance that is shown to be tight for various cases of interest.
In this paper, we discuss the internet low bit rate codec (iLBC) with an emphasis on the frame-independent long-term prediction. The frame-independent long-term prediction is a method to exploit pitch-lag correlations...
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In this paper, we discuss the internet low bit rate codec (iLBC) with an emphasis on the frame-independent long-term prediction. The frame-independent long-term prediction is a method to exploit pitch-lag correlations in the encoding of speech without suffering multiple-frame speech degradation in connection with transmission loss. We present mean opinion scores for the iLBC codec and show by means of signal examples how the nature of degradation in a predictive codec based on frame-independent long-term prediction differs from that of traditional CELP codecs.
We present a functional model of V4 area in visual cortex based on predictive coding scheme, in which the prediction is compared with three kinds of images corresponding to three kinds of image representations which a...
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We present a functional model of V4 area in visual cortex based on predictive coding scheme, in which the prediction is compared with three kinds of images corresponding to three kinds of image representations which are projected through the filters with three different sizes of spatial resolutions. The prediction is represented as a combination of elemental figures. These representations are generated by the response property of main neurons in V1 and V4 areas that the main neurons respond selectively to a limited band of frequencies of spatial brightness distribution. We propose the functional role of elemental figures in invariant perception of object form in visual cortex.
In this paper, we propose a color segmentation algorithm based on contrast information and adaptive thresholds. Given a color image, instead of the commonly used achromatic difference and chromatic difference, we use ...
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In this paper, we propose a color segmentation algorithm based on contrast information and adaptive thresholds. Given a color image, instead of the commonly used achromatic difference and chromatic difference, we use achromatic contrast and chromatic contrast to represent the significance of boundary. To fit for human visual perception, adaptive thresholds are applied to suppress perceptually faint boundaries. A complete segmentation scheme is proposed and the simulation results demonstrate the superiority of this approach in providing reasonable and reliable color segmentation.
In many applications surfaces with a large number of primitives occur. Geometry compression reduces storage space and transmission time for such models. A special case is given by polygonal isosurfaces generated from ...
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In many applications surfaces with a large number of primitives occur. Geometry compression reduces storage space and transmission time for such models. A special case is given by polygonal isosurfaces generated from gridded volume data. However most current state-of-the-art geometry compression systems do not capitalize on the structure that is characteristic of such isosurfaces, namely that the surfaces are defined by a set of vertices on edges of the grid. In a previous paper we proposed a compression method for isosurfaces that exploits this feature. In this paper we use the same coding approach, however, including context models for the encoding of the symbol streams. We report improved compression ratios for complex isosurfaces from a CT scan of a human head Our coder outperformed state-of-the-art general purpose geometry compression methods. We also report results obtained by two predictive coding methods based on least squares function fitting and a surface relaxation algorithm.
At a given bitrate, and for a given coding structure, an embedded speech coder often shows a loss in quality when compared to a corresponding non-embedded coder. This paper presents a general framework to investigate ...
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At a given bitrate, and for a given coding structure, an embedded speech coder often shows a loss in quality when compared to a corresponding non-embedded coder. This paper presents a general framework to investigate how this loss depends on common design choices such as the frame length, prediction order and quantizer dimensions used by the coders. The results show that predictive and transform predictive coding schemes, and schemes which normalize energy over short intervals in time and frequency, may see smaller losses when used in embedded designs than compared to other coding paradigms.
Lossless compression of electroencephalograph (EEG) data is of great interest to the biomedical research community. Lossless compression through neural network is achieved by using the net as a predictor and coding th...
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Lossless compression of electroencephalograph (EEG) data is of great interest to the biomedical research community. Lossless compression through neural network is achieved by using the net as a predictor and coding the prediction error in a lossless manner. The predictive neural network uses a certain number of past samples to predict the present one and in most cases, the differences between the actual and predicted values are zero or close to zero. Entropy coding techniques such as Huffman and arithmetic coding are used in the second stage to achieve a high degree of compression. predictive coding schemes based on single- layer and multi-layer perceptron networks and recurrent network models are investigated in this paper. Compression results are reported for EEG's recorded under various clinical conditions. These results are compared with those obtained by using linear predictors such as FIR and lattice filters.
This paper presents a method for distortion-optimized streaming of predictively coded video over packet networks with varying delay. In networks with significant delay variations, coded video frames can arrive late at...
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This paper presents a method for distortion-optimized streaming of predictively coded video over packet networks with varying delay. In networks with significant delay variations, coded video frames can arrive late at the decoder and miss their respective display deadlines. Furthermore, due to predictive coding, a late frame can also prevent a number of subsequent frames from being displayed properly, where the number of affected frames or degree of distortion depends on the particular coding dependencies of the late frame. In this paper, we present an optimized video streaming strategy based on frame reordering for networks with significant delay variations. This streaming strategy minimizes distortion by exploiting the fact that different late frames result in different degrees of distortion. We model the router-induced delay in a wired network with an analytical PDF and we model the link-layer retransmission delay of a wireless network with the 3GPP specification for W-CDMA radio link control. We compute the distortion for different frame reorderings using the network delay models and a source model that accounts for the prediction dependencies of predictively coded video. Our optimized streaming strategies are shown to reduce the number of late frames by 14 to 23% for the situations examined.
This paper presents the adaptation via evolutionary techniques of a pixel predictor for lossless image compression. The pixel prediction is based on a linear combination of some neighbor pixels. The evolutionary algor...
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This paper presents the adaptation via evolutionary techniques of a pixel predictor for lossless image compression. The pixel prediction is based on a linear combination of some neighbor pixels. The evolutionary algorithm selects the coefficients and the pixels involved in the pixel prediction. Experiments carried out on gray level images of the proposed system show a performance comparable and in some cases better than existing predictive coding techniques.
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