Image processing for HD-MAC bandwidth compression

HD-MAC uses three basic techniques to reduce the bandwidth of the transmitted signal while retaining as much of the original image quality as possible. These are diagonal filtering, the exchange of spatial and temporal resolution and motion-compensated temporal interpolation. Bandwidth reduction by a factor of two may be obtained by diagonal filtering. An additional factor of two is achieved by exchanging spatial and temporal resolution. Motion-compensated interpolation is used to minimise the subjective effect of the second process. The paper describes how these image processing techniques are employed by the HD-MAC system which has been selected by the EU-95 HDTV project following much development work. Only the luminance processing is described, but the chrominance processing uses the same techniques