Video coding with wavelet transform on the very low bit rate communication channel

In this paper, we present a moving image coding system which uses wavelet transform for the videophone on a very low bit rate communication channel (10 K bps PSTN). There are two requirements for our coding system: the good subjective quality for low bit rate coding and the suitability for progressive transmission. To satisfy the requirements, we use multifrequency motion estimation which estimates motion for each frequency bands. After the motion estimation, we can assign less bits to the motion estimation error in the high frequency bands because the human is insensitive to the change in high frequency components in the case of moving image. The experimental results confirm that our approach out-performs discrete cosine transform coding schemes in terms of the subjective quality because there are no blocking effects, and moreover, the wavelet transform in the approach supports the progressive transmission in itself.