R-D optimized tree-structured compression algorithms with discrete directional wavelet transform
- 作者：Hui Liu ; Siliang Ma
- 关键词：S-WT ; Dominant directions ; DVM ; SPECK ; Rate-distortion ; Quad-tree ; Bit allocation
- 刊名：Journal of Computational and Applied Mathematics
- 出版年：2008
- 期刊代码：72_03770427
- 类别：cp
- 出版时间：15 September 2008
- 卷：219
- 期：1
- 页码：302-311
- 文件大小：637 K
摘要
A new image coding method based on discrete directional wavelet transform (S-WT) and quad-tree decomposition is proposed here. The S-WT is a kind of transform proposed in [V. Velisavljevic, B. Beferull-Lozano, M. Vetterli, P.L. Dragotti, Directionlets: anisotropic multidirectional representation with separable filtering, IEEE Trans. Image Process. 15(7) (2006)], which is based on lattice theory, and with the difference with the standard wavelet transform is that the former allows more transform directions. Because the directional property in a small region is more regular than in a big block generally, in order to sufficiently make use of the multidirectionality and directional vanishing moment (DVM) of S-WT, the input image is divided into many small regions by means of the popular quad-tree segmentation, and the splitting criterion is on the rate-distortion sense. After the optimal quad-tree is obtained, by means of the embedded property of SPECK, a resource bit allocation algorithm is fast implemented utilizing the model proposed in [M. Rajpoot, Model based optimal bit allocation, in: IEEE Data Compression Conference, 2004, Proceedings, DCC 2004.19]. Experiment results indicate that our algorithms perform better compared to some state-of-the-art image coders.