High-Resolution Still-Image Transmission Based on CCITT H.261 Codec

This letter presents an efficient scheme for transmitting high resolution still images based on a lower resolution CCITT H.261 codec. Two transmission schemes based on a subsampling approach are studied in terms of image quality, transmission delay, and compatibility with H.261. It is found that the sequential frame-repeat scheme provides a good compromise among the different criteria. In addition, a simple progressive-reconstruction procedure for the decoded subimages is described. Simulation results show that the visual effects of such a reconstruction procedure is quite pleasing