Design and analysis of two-channel high definition television systems
A technique for the analysis of two-channel high-definition television (HDTV) transmission systems is presented. Design methods based on limitations due to the combined spatial and temporal characteristics of the human visual system (HVS) are developed. The concepts of resolution imbalance, recognizability, and spatial-temporal multiplexing are explained. The design and analysis of two-channel NTSC-compatible HDTV systems having an aspect ratio of 16:9 with double the vertical and horizontal resolution of the present NTSC system is described. It is shown that such a system requires more than two channels for transmission. Signal processing techniques are suggested to improve the quality of the images without using any extra channels. Time multiplexing of different frequency bands are used to exploit the psychovisual redundancies of the HVS to reduce the number of pels to be transmitted. Finally, comparing the spatial resolutions of the reconstructed images by a two-channel HDTV system with that of the HVS, it is found that the spatial resolution are not yet as good as that of the HVS. >