Fixed, adaptive, and motion compensated interpolation of interlaced TV pictures

All current broadcast TV systems make use of interlace to reduce the bandwidth required. However this makes it difficult to perform processes such as freeze frame, slow motion, picture geometry manipulation, standard conversion and display up-conversion. These would prefer to treat each field separately, but each field contains only half of the TV lines. The ability to perform good interpolation of interlaced TV pictures would thus improve the quality of all these processes. This is very relevant to the question of whether to use interlace in any future (higher definition) TV systems. This paper describes how computer simulation of complex adaptive interpolation has led to the development of high performance fixed interpolators. Since the authors have found that a fixed interpolator can give very good results, they have built a real-time 625/50/2:1 to 1250/50/2:1 line rate up-converter, which will form part of the 1988 EUREKA project 95 (HDTV) demonstration. Initial tests with motion compensation are also described. Further developments are continuing within the EUREKA project to contribute to a more advanced system in 1989/90