Global motion estimation and compensation are important research issues in video compression. The main difficulty in global motion estimation resides in the disturbance of independently moving objects. The algorithm p...
详细信息
ISBN:
(纸本)0819424358
Global motion estimation and compensation are important research issues in video compression. The main difficulty in global motion estimation resides in the disturbance of independently moving objects. The algorithm presented in this paper exploits global motion information not only from stationary objects and the image background, but also from independently moving objects. Simulation results show that the new algorithm is more robust to the disturbance of independently moving objects, and computationally faster than an algorithm based on least-square approximation.
In this work we discuss several approaches fur designing fractal quantizers in the context of hybrid wavelet-fractal image compression algorithms. Moreover different subband-structures are compared concerning their su...
详细信息
ISBN:
(纸本)0819427497
In this work we discuss several approaches fur designing fractal quantizers in the context of hybrid wavelet-fractal image compression algorithms. Moreover different subband-structures are compared concerning their suitability for subsequent fractal quantization.
In this work we apply techniques originating from classical fractal still-image coding to block-matching motion compensation algorithms for digital video compression. Especially the method of adapting the gray-values ...
详细信息
ISBN:
(纸本)0819427497
In this work we apply techniques originating from classical fractal still-image coding to block-matching motion compensation algorithms for digital video compression. Especially the method of adapting the gray-values in image blocks of the current frame to those in blocks of the reference-frame shows promising performance.
An algorithm for image compression, based on local histogram analysis, is presented. A given image is compressed by dividing the image into nonoverlapping square blocks and coding the edge information in each block. T...
详细信息
ISBN:
(纸本)0819424358
An algorithm for image compression, based on local histogram analysis, is presented. A given image is compressed by dividing the image into nonoverlapping square blocks and coding the edge information in each block. The edge information is extracted by first differentiating the original image, quantising the differential image, then invistigated the local histogarm of small blocks of the differential image. Depending on the behaviour of the local histograms in the differential image, the corresponding blocks in the original image are classified into visually active and visually continuous blocks. The visually continous blocks are coded using the mean value only. A visually active block is coded using the location and orientation of the edge within the block. As a result, the compression ratio of the proposed algorithm depends on the behaviour of the local histogram, which in turn depends heavely on the quantisation process of the differential image. In this paper, the effect of the quantisation of the differential image on the compression ratio and the image quality is discussed.
In this paper we propose an image coding scheme based on the polynomial transform and multiresolution analysis. The polynomial transform is an image representation model that mimics some properties of the human visual...
详细信息
ISBN:
(纸本)0819424358
In this paper we propose an image coding scheme based on the polynomial transform and multiresolution analysis. The polynomial transform is an image representation model that mimics some properties of the human visual system, and which we use in order to model edges in terms of their characteristic parameters. Based on the polynomial transform, we build a pyramidal hierarchical predictive scheme for image coding. The feature parameters that we encode are: local average, edge orientation, edge position and edge magnitude.
Although block-based image compression techniques seem to be straightforward to implement on parallel MIMD architectures, problems might arise due to architectural restrictions on such parallel machines (e.g. memory c...
详细信息
ISBN:
(纸本)0819424358
Although block-based image compression techniques seem to be straightforward to implement on parallel MIMD architectures, problems might arise due to architectural restrictions on such parallel machines (e.g. memory constraints on distributed memory architectures). In this paper we discuss possible solutions to such problems occurring in different image compression techniques. Experimental results are included for adaptive wavelet block coding and fractal compression.
Traditional objective metrics for the quality measure of coded images such as the mean squared error (MSE) and the peak signal-to-noise ratio (PSNR) do not correlate with the subjective human visual experiences well, ...
详细信息
ISBN:
(纸本)0819424358
Traditional objective metrics for the quality measure of coded images such as the mean squared error (MSE) and the peak signal-to-noise ratio (PSNR) do not correlate with the subjective human visual experiences well, since they do not take human perception into account. Quantification of artifacts resulted from lossy image compression techniques is studied based on a human visual system (HVS) model and the time-space localization property of the wavelet transform is exploited to simulate HVS in this research. As a result of our research, anew image quality measure by using the wavelet basis function is proposed. This new metric works for a wide variety of compression artifacts. Experimental results are given to demonstrate that it is more consistent with human subjective ranking.
This paper presents a wavelet based image compression algorithm using subjective thresholding and quantization of the wavelet coefficients. Subjective compression techniques use the properties of the Human visual Syst...
详细信息
ISBN:
(纸本)0780336763
This paper presents a wavelet based image compression algorithm using subjective thresholding and quantization of the wavelet coefficients. Subjective compression techniques use the properties of the Human visual System (HVS) to eliminate redundant information in an image. By combining the wavelet transform coefficients with psychovisual thresholding and quantization schemes, a coding result of 0.31 bits per pixels has been obtained with weighted PSNR of 39.07 dB.
In this paper, a new technique is developed to enhance the. quality of JPEG compressed images. Based on the principle of learning by examples, the new method constructs the enhancement system adaptively. In order not ...
详细信息
ISBN:
(纸本)0819427497
In this paper, a new technique is developed to enhance the. quality of JPEG compressed images. Based on the principle of learning by examples, the new method constructs the enhancement system adaptively. In order not to incur overheads, the processing system is designed io have only 7 parameters which can also be estimated off-line. Extensive simulations have been performed, results show significant improvements of both subjective and objective quality of JPEG compressed images. It is also observed that the new techniques performs competitively to state of the art techniques and is computationally more efficient.
By dynamically distributing the channel capacity among video programs according to their respective scene complexities, joint coding has been shown to be more efficient than independent coding for compression of multi...
详细信息
ISBN:
(纸本)0819424358
By dynamically distributing the channel capacity among video programs according to their respective scene complexities, joint coding has been shown to be more efficient than independent coding for compression of multiple video programs [3]. This paper examines the bit allocation issue for joint coding of multiple video programs and provides a bit allocation strategy that results in uniform picture quality among programs as well as within a program.
暂无评论