SUB-SAMPLING TRANSMISSION SYSTEM FOR IMPROVING TRANSMITTED PICTURE QUALITY IN TIME-VARYING PICTURE REGION OF WIDE-BAND COLOR PICTURE SIGNAL

摘要

A system for narrow-band transmission by sub-sampling wide-band color picture signal for high definition television broadcasting, in which the resolution and overall picture quality of a reproduced color time-varying picture are improved by using the following picture signal processings instead of a conventional line offset sub-sampling every field which lowers the resolution of the time-varying picture in comparison with that of a static picture subjected to an offset sub-sampling using a sampling pattern cycling every two frames. An offset sub-sampling between the fields is applied to a color difference signal in the time-varying picture region. Signal processings which include a frequency band limitation for preventing aliasing distortion accompanying the sub-sampling and an interpolation in reproducing are performed between the fields in the form of it being completed every frame. Further, with respect to the time-varying picture region where its movement in the vertical direction is small, a similar sub-sampling and signal processing are performed for its luminance signal too.