A DCT-based embedded image coder using wavelet structure of dct for very low bit rate video codec

This paper presents an efficient DCT-based embedded image coder designed for I(Intra)-frame coding in very low bit rare video codec. Motivated by the recognition that a DCT (Discrete Cosine Transform) on NxN blocks of an image can be viewed as a wavelet decomposition with a uniform NxN-subband decomposition, the proposed coder rearranges the DCT transformed image into 2-level wavelet pyramid structure and makes use of improved embedded zerotree coding. The proposed rearrangment structure is quite well coupled with a embedded zerotree coding. Resulting DCT-based embedded image coder shows the better rate-distortion performance than conventional H.263 and MPEG4 as well as EZW-style coders. Also, the performance of the proposed new coder is comparable to that of state-of-art still image compression methods. In addition, embedded feature of the proposed coder makes it possible to encode I-frame at the exactly chosen bit I-ate.