A new still image compression algorithm based on the multi-threshold wavelet coding (MTWC) technique is proposed in this work. It is an embedded wavelet coder in the sense that its compression ratio can be controlled ...
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ISBN:
(纸本)0819426628
A new still image compression algorithm based on the multi-threshold wavelet coding (MTWC) technique is proposed in this work. It is an embedded wavelet coder in the sense that its compression ratio can be controlled depending on the bandwidth requirement of image transmission. At low bite rates, MTWC can avoid the blocking artifact from JPEG to result in a better reconstructed image quality. An subband decision scheme is developed based on the rate-distortion theory to enhance the image fidelity. Moreover, a new quantization sequence order is introduced based on our analysis of error energy reduction in significant and refinement maps. Experimental results are given to demonstrate the superior performance of the proposed new algorithm in its high reconstructed quality for color and gray level image compression and low computational complexity. Generally speaking, it gives a better rate-distortion tradeoff and performs faster than most existing state-of-the-art wavelet coders.
A new embedded wavelet coder called the multithreshold wavelet coder (MTWC) was proposed in this research. The new coder was motivated by a careful analysis of the rate-distortion performance and the coding efficiency...
详细信息
ISBN:
(纸本)0819425869
A new embedded wavelet coder called the multithreshold wavelet coder (MTWC) was proposed in this research. The new coder was motivated by a careful analysis of the rate-distortion performance and the coding efficiency of existing embedded wavelet coders. Unlike other proposed embedded wavelet coders which use a single initial threshold in their successive approximate quantization (SAQ), MTWC uses different initial thresholds in different subbands and applies a subband decision scheme to decide which subband should be coded in sequence. It is shown with experimental results that MTWC has a better rate-distortion tradeoff at higher bit rates and a lower computational complexity than other embedded wavelet coders. Furthermore, MTWC can be easily applied to an image coder with the wavelet packet transform, whose performance is significantly better than the image coder with the pyramid wavelet transform for texture-dominant imagery.
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