In the adaptive intra refresh method adopted in MPEG-4, a case that errors occurring in transmission propagate frame to frame and also spread inside a frame is still observed. This paper proposes a modified method for...
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In the adaptive intra refresh method adopted in MPEG-4, a case that errors occurring in transmission propagate frame to frame and also spread inside a frame is still observed. This paper proposes a modified method for performing the intra refresh adaptively. This method applies an intra-block encoding scheme to macro-blocks according to the number of pixels referred in the motion compensated predictive coding scheme, instead of applying it to moving macro-blocks just periodically in a fixed order inside the frame. Simulation results using test sequences demonstrate that this method reduces error propagation in shorter term than the conventional method, while causing less increase of the number of codes. The number of error spread pixels decreases by about 30% in the proposal method
Motion information scalability is important for scalable bit-stream adaptation on low bit-rates, when motion rate occupies a significant portion of the total bit-rate. This type of scalability can be achieved by layer...
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Motion information scalability is important for scalable bit-stream adaptation on low bit-rates, when motion rate occupies a significant portion of the total bit-rate. This type of scalability can be achieved by layered representation of motion block partitioning and predictive coding of associated motion vectors across these layers. So far, several approaches for creating layered motion structure targeting quality scalability have been proposed and in this paper their accuracy is evaluated. For that purpose optimal motion models have been found. It has been shown that simple evaluation of reconstruction error at the encoder side improves suboptimal modeling techniques.
Highly scalable video compression based on invertible motion adaptive lifting transforms has emerged as a promising area in image processing research and an important component in interactive multimedia technology. Ho...
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Highly scalable video compression based on invertible motion adaptive lifting transforms has emerged as a promising area in image processing research and an important component in interactive multimedia technology. However, within this feed-forward framework, the potential for coding efficiency improvement and its impact on random accessibility still has not been carefully assessed. In this paper, we compare the merits of several three-dimensional context coding strategies from an information-theoretic perspective. The variation in random access cost in response to coding parameter adjustments is analyzed, for a variety of spatial and temporal configurations.
A recent paper1 discusses prediction and interpolation for data compression of ECG. This communication points out that both methods can be viewed as linear filtering. They are therefore equivalent and give the same re...
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A recent paper1 discusses prediction and interpolation for data compression of ECG. This communication points out that both methods can be viewed as linear filtering. They are therefore equivalent and give the same result in terms of the amount of data compression achieved.
Aiming at the characteristics of the subway tunnel crack images, this paper presents a new method of subway tunnel crack image compression based on region of interest and motion estimation. It contains three key parts...
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Aiming at the characteristics of the subway tunnel crack images, this paper presents a new method of subway tunnel crack image compression based on region of interest and motion estimation. It contains three key parts: the method of key frame image compression based on Discrete Cosine Transformation, the method of internal frame image compression based on forward predictive coding and motion estimation, the method of lossless image compression based on crack information database and suspected crack regions. The simulation experiment results show that this method can not only enhance the image compression ratio without losing any information of images in the region of interest, but also interface with the existing subway tunnel crack recognition system very well and make good use of the data from the crack recognition system database and the images in the disk array.
A robust speech feature extraction procedure, by kernel regression nonlinear predictive coding, is presented. Features maximally insensitive to additive noise are obtained by growth transformation of regression functi...
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A robust speech feature extraction procedure, by kernel regression nonlinear predictive coding, is presented. Features maximally insensitive to additive noise are obtained by growth transformation of regression functions spanning a reproducing kernel Hilbert space (RKHS). Experiments on TI-DIGIT demonstrate consistent robustness of the new features to noise of varying statistics, yielding significant improvements in digit recognition accuracy over identical models trained using Mel-scale cepstral features and evaluated at noise levels between 0 and 30 dB SNR.
We develop practical rate distortion bounds for speech coding based on composite source models and the PESQ-MOS distortion measure. Specifically, the bounds and formulated using composite source models for speech, the...
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We develop practical rate distortion bounds for speech coding based on composite source models and the PESQ-MOS distortion measure. Specifically, the bounds and formulated using composite source models for speech, the rate distortion function for Gaussian autoregressive sources, the classical reverse water-filling result, and conditional rate distortion theory, along with a recently devised MSE-to-PESQ_MOS mapping. The resulting rate distortion bounds are shown to lower bound the performance of the AMR, G.729, and G.718 standardized codecs, and based on the tightness of these bounds, to indicate how the performance of voice codecs might be improved.
Multi-view image coding benefits from knowledge of the depicted scene's 3D geometry. To exploit geometry information for compression, two different approaches can be distinguished. In texture-based coding, images ...
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Multi-view image coding benefits from knowledge of the depicted scene's 3D geometry. To exploit geometry information for compression, two different approaches can be distinguished. In texture-based coding, images are converted to texture maps prior to compression. In image-based predictive coding, geometry is used for disparity compensation and occlusion detection between images. coding performance of both approaches depends on the accuracy of the available geometry model. Texture-based and image-based coding are compared with regard to the influence of geometry accuracy on coding efficiency. The results are theoretically explained. Experiments with natural as well as synthetic image sets show that texture-based coding is more sensitive to small geometry inaccuracies than image-based coding. For approximate geometry models, image-based coding performs best, while texture-based coding yields superior coding results if scene geometry is exactly known.
This paper presents a new framework for adaptive temporal filtering in wavelet interframe codecs, called the unconstrained motion compensated temporal filtering (UMCTF). This framework allows flexible and efficient te...
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This paper presents a new framework for adaptive temporal filtering in wavelet interframe codecs, called the unconstrained motion compensated temporal filtering (UMCTF). This framework allows flexible and efficient temporal filtering by combining the best features of motion compensation, used in predictive coding, with the advantages of interframe scalable wavelet video coding schemes. UMCTF provides higher coding efficiency, improved visual quality and flexibility of temporal and spatial scalability, higher coding efficiency and tower decoding delay than conventional MCTF schemes. Furthermore, UMCTF can also be employed in alternative open-loop scalable coding frameworks using DCT for the texture coding.
This paper describes an execution unit capable of computing the Paeth predictor, as used in the portable network graphics (PNG) standard. PNG is a rather new, lossless compression method for real-world pictures. It fe...
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This paper describes an execution unit capable of computing the Paeth predictor, as used in the portable network graphics (PNG) standard. PNG is a rather new, lossless compression method for real-world pictures. It features five prediction schemes, of which the modified Paeth predictor is the most computational intensive. This paper focuses on a hardware implementation of the Paeth predictor and a hardware Paeth codec capable of computing three different quantities: the Paeth predictor of three inputs, the difference of the current pixel and the Paeth predictor of the other inputs (coding), and the sum of the coded input and the Paeth predictor of the other three inputs (decoding). The proposed Paeth codec takes two cycles, where a cycle is comparable to an general purpose ALU cycle. Depending on the mode of operation, the proposed mechanism produces the predictor or the (de/en)-coded pixel value.
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