Space-frequency motion model for subband/wavelet video coding

Wavelet-transform lossy coding achieves state-of-the-art performance for still images. For motion-compensated interframes, however, block-transform coding is preferred due to its ability to intracode poorly predicted blocks. Space-frequency half-pixel block matching is a new approach that enables hybrid block-motion-compensated wavelet-coded interframes to efficiently code blocks with lour temporal correlation of high frequency details. Architectural compatibility is maintained and little additional complexity is required to achieve superior performance. Simulation results with both fixed-size block matching and hierarchical variable-sized block matching indicate that a blocksize-constrained adaptive choice of interpolation filter improves PSNR by .75dB for hybrid wavelet interframe coding (verses +.25dB for H.263) at multimedia quality bitrates. For H.263, bitrate reduction can approach 30% at higher rates. The method is perceptually successful where a block-translational motion model fails, efficiently reducing falsely introduced detail.