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Flexible Zerotree Coding of Wavelet Coefficients
Flexible Zerotree Coding of Wavelet Coefficients
Joo, Sanghyun
6121
Kikuchi, Hisakazu
6122
Sasaki, Shigenobu
6123
Shin, Jaeho
6124
image compression
wavelet transform
zerotree coding
We introduce an extended EZW coder that uses flexible zerotree coding of wavelet coefficients. A flexible parent-child relationship is defined so as to exploit spatial dependencies within a subband as well as hierarchical dependencies among multi-scale subbands. The new relationship is based on a particular statistics that a large coefficient is more likely to have large coefficients in its neighborhood in terms of space and scale. In the flexible relationship, a parent coefficient in a subband relates to four child coefficients in the next finer subband in the same orientation. If each of the children is larger than a given threshold, the parent extends its parentship to the neighbors close to its conventional children. A probing bit is introduced to indicate whether a significant parent has significant children to be scanned. This enables us to avoid excessive scan of insignificant coefficients. Also, produced symbols are re-symbolized into simple variable-length binary codes to remove some redundancy ac cording to a pre-defined rule. As a result, the wavelet coefficients can be described with a small number of binary symbols. This binary symbol stream gives a competitive performance without an additional entropy coding and thus a fast encoding/decoding is possible. Moreover, the binary symbols can be more compressed by an adaptive arithmetic coding. Our experimental results are given in both binary-coded mode and arithmetic-coded mode. Also, these results are compared with those of the EZW coder.
journal article
The Institute of Electronics, Information and Communication Engineers
1999-06
application/pdf
IEICE transactions on fundamentals of electronics, communications and computer sciences
6
E82-A
1117
1125
IEICE transactions on fundamentals of electronics, communications and computer sciences
AA10826239
09168508
https://niigata-u.repo.nii.ac.jp/record/1897/files/1_0021.pdf
eng
http://www.ieice.org/jpn/trans_online/
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