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	Wavelet-based contourlet coding using SPECK algorithm (EI CONFERENCE) 会议论文 OAI收割 2008 9th International Conference on Signal Processing, ICSP 2008, October 26, 2008 - October 29, 2008, Beijing, China Xiu-Wei T.; Xi-Feng Z.; Tie-Fu D. 收藏 \| 浏览/下载：55/0 \| 提交时间：2013/03/25 We proposed a new still image compression algorithm called CSPECK witch was constructed by the wavelet-based contourlet transform (WBCT) and set partitioning embedded block coding (SPECK). In the WBCT the high frequency sub-band decomposed by the wavelet transform was further decomposed into multiple directional sub-bands by directional filter bank so as to explain the edge and texture of the image more sparsely. The SPECK algorithm exhibits lower complexity and more efficient compression ratio than SPIHT based on WBCT. Experimental results demonstrate that the proposed method is efficient in coding images that possess mostly textures and contours. The simulation results also show that this new coding algorithm increases the PSNR over CSPIHT. 2008 IEEE.
	High speed, low memory image coding using zero blocks of wavelet coefficients (EI CONFERENCE) 会议论文 OAI收割 4th International Conference on Image and Graphics, ICIG 2007, August 22, 2007 - August 24, 2007, Chengdu, China 作者: Zhang T.; Yang W.-G. 收藏 \| 浏览/下载：33/0 \| 提交时间：2013/03/25 We propose a new high speed low memory SPECK image coder based on the form of block-unit states called LBUS-SPECK which uses the form of block-unit states and the form of block exponents to substitute LIS and LSP of SPECK. A form of block-unit states is introduced to store the significance flag of coefficients and the value of the block-unit exponents. A form of block exponents is introduced to store the block exponents which are used to represent the max coefficient in a decomposed block. A new block depth-finding strategy is developed for searching insignificant sets at sorting stage. Experimental results show that the obtained PSNR values for the decoded images are very close to those of SPECK algorithm and the memory consumption is reduced by 9 times the encoding timing is saved about 15%. Comparing with SPECK algorithm this algorithm not only has better performance of the decoded images but also is easy to implement especially it provides an efficient way for hardware implementation of wavelet embedded block coding. 2007 IEEE.
	Wavelet-fractal based compression of ophthalmic image (EI CONFERENCE) 会议论文 OAI收割 ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China Xiu-Ying Z.; Lin-Pei Z. 收藏 \| 浏览/下载：24/0 \| 提交时间：2013/03/25 This study is designed to determine the degree and methods of digital image compression to produce ophthalmic images of sufficient quality for transmission and diagnosis. Fractal based compression techniques which provide a large compression ratio for grayscale images have been reported in the literature. Fractal coding is based on the fractal theory of iterated transformations. But it's searching and mapping algorithm cannot address the need of real-time. To improve the real-time performance of the algorithm we use wavelet transforms to decompose images. The wavelet transform is a natural tool for analyzing fractal block coders since wavelet bases possess the same type of dyadic self-similarity that fractal coders seek to exploit. We propose a method of fractal coding the weighted wavelet subtree. Experimented results show that the improved hybrid image can improve the PSNR of the rebuild image at the same compression ratio.
	Fast block-based image restoration employing the improved best neighborhood matching approach 期刊论文 OAI收割 IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART A-SYSTEMS AND HUMANS, 2005, 卷号: 35, 期号: 4, 页码: 546-555 作者: Li, W; Zhang, D; Liu, ZY; Qiao, XZ \| 收藏 \| 浏览/下载：24/0 \| 提交时间：2019/12/16 best neighborhood matching (BNM) algorithm block-based coding image computation complexity image restoration transmission error