A Multi-Threshold Embedded Zerotree Wavelet Coder
Eui Sung Kang, Toshihisa Tanaka, Tea Hyung Lee, Sung-Jea Ko · 1998
In this paper, a novel and simple embedded wavelet coder, called a multi-threshold embedded zerotree wavelet coder, is proposed. The well-known embedded zerotree wavelet (EZW) coder uses the successive approximation quantization (SAQ) process and zerotree structures of wavelet coefficients. The EZW coder scans iteratively whole wavelet coefficients during the SAQ process, which decreases the coding efficiency considerably. In the proposed scheme, we scan only significant subbands using the significant test with the multi-threshold. The multi-threshold obtained from the coefficient with the maximum magnitude in each subband is used to determine whether a subband has significant coefficients or not. Since it is not necessary to encode the insignificant subbands having no significant coefficients during the SAQ process, we reduce significantly the redundancy generated by scanning higher subbands. Experimental results show that the proposed method outperforms popular image coders such as E...