A Multi-threshold Embedded Zerotree Wavelet Coder

| In this paper, a novel and simple embedded wavelet coder, called a multi-threshold embedded zerotree wavelet coder, is proposed. The well-known embedded ze-rotree wavelet (EZW) coder uses the successive approximation quantization (SAQ) process and zerotree structures of wavelet coeecients. The EZW coder scans iteratively whole wavelet coeecients during the SAQ process, which decreases the coding eeciency considerably. In the proposed scheme, we scan only signiicant subbands using the signiicant test with the multi-threshold. The multi-threshold obtained from the coeecient with the maximum magnitude in each subband is used to determine whether a subband has signiicant coeecients or not. Since it is not necessary to encode the insignificant subbands having no signiicant coeecients during the SAQ process, we reduce signiicantly the redundancy generated by scanning higher subbands. Experimental results show that the proposed method outperforms popular image coders such as EZW and JPEG.