Error-resilience is an important feature of any image or video coding algorithm associated with transmission over noisy or multipath channels. in this paper, we present a robust coding algorithm based on a modified ve...
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ISBN:
(纸本)0819427497
Error-resilience is an important feature of any image or video coding algorithm associated with transmission over noisy or multipath channels. in this paper, we present a robust coding algorithm based on a modified version of the zerotree coding technique, The algorithm provides significantly improved error-resilience with minimum added redundancy while still. retaining the efficiency and scalability of tile original technique.
Wavelet-based methods have become most popular for the compression of two-dimensional medical images and sequences. The standard implementations consider data sizes that are powers of two. There is also a large body o...
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Wavelet-based methods have become most popular for the compression of two-dimensional medical images and sequences. The standard implementations consider data sizes that are powers of two. There is also a large body of literature treating issues such as the choice of the "optimal" wavelets and the performance comparison of competing algorithms. With the advent of telemedicine, there is a strong incentive to extend these techniques to higher dimensional data such as dynamic three-dimensional (3-D) echocardiography [four-dimensional (4-D) datasets]. One of the practical difficulties is that the size of this data is often not a multiple of a power of two, which can lead to increased computational complexity and impaired compression power. Our contribution in this paper is to present a genuine 4-D extension of the well-known zerotree algorithm for arbitrarily sized data. The key component of our method is a one-dimensional wavelet algorithm that can handle arbitrarily sized input signals. The method uses a pair of symmetric/antisymmetric wavelets (10/6) together with some appropriate midpoint symmetry boundary conditions that reduce border artifacts. The zerotree structure is also adapted so that it can accommodate noneven data splitting. We have applied our method to the compression of real 3-D dynamic sequences from clinical cardiac ultrasound examinations. Our new algorithm compares very favorably with other more ad hoe adaptations (image extension and tiling) of the standard powers-of-two methods, in terms of both compression performance and computational cost. It is vastly superior to slice-by-slice wavelet encoding. This was seen not only in numerical image quality parameters but also in expert ratings, where significant improvement using the new approach could be documented. Our validation experiments show that one can safely compress 4-D data sets at ratios of 128:1 without compromising the diagnostic value of the images. We also display some more extreme compre
Colour images are widely used in computer applications. Uncompressed digital images require considerable storage capacity and transmission bandwidth. Efficient image compression solutions are becoming more critical wi...
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Colour images are widely used in computer applications. Uncompressed digital images require considerable storage capacity and transmission bandwidth. Efficient image compression solutions are becoming more critical with the recent growth of data intensive, multimediabased web applications. DCT (relative to the DFT) has the advantages of real valued, better energy compaction (much of the signal energy can be represented by only a few coefficients), experimentally observed to work well and coefficients are nearly uncorrelated. Fractal coding is a kind of VQ coding but Less than stellar compression ratio for ‘good’ image reconstruction. In this paper we implement colour image compression using Discrete Cosine Transform (DCT), VQ coding and a new proposed method that merges DCT and wavelet transform is implemented. Experiment results showed that the performance of new proposed algorithm is effective and can obtain very high compression ration
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