Wavelet picture coding and its several problems of the application to the interlace HDTV and the ultra-high definition images

A new image coding method utilizing the wavelet transform, JPEG2000, has been developed. In this report, we consider several types of visual distortion observed in moving HDTV pictures and ultra-high definition pictures compressed by wavelet transform coding, and describe measures to reduce them. So-called "flicker artifacts" are visually decreased by visual weighting and the mechanism is interpreted by Weber's law. The characteristic distortion named "comb-tooth artifacts" caused by the combination of subband decomposition and the interlaced TV signal structure is discussed, and a preprocessing method is proposed to counter it. The relation between the resolution levels of the subband decomposition and the distortion is investigated by coding experiments on ultra-high definition pictures.