inaccurate focusing, limited-resolution image sensor, lossy compression,
and down-scaling. In a UHD TV system, for example,
the image degradation model is shown in Fig. 1, where the natural
scene is first degraded by a camera system and the compression
process to produce a high-definition (HD) image. In order to
use the HD image in the UHD TV, up-scaling is performed by
interpolation.