Quality scalable coding of selected region

If a region is semantically more important than others, it is appropriate that a image compression scheme is capable of handling the regional semantic difference because the information loss of the interested region is more severe. We propose the quality scalable coding with its model by introducing the quality scale parameter. It is more extended and generalized image compression philosophy than a conventional coding. As an implementation of the proposed quality scalable coding, a H.263 based scheme is presented. This scheme can control the temporal and spatial quality efficiently, and improve the reconstructed image quality of the interested region.