Hi-Vision is a new television system that Japan plications have already begun in some of these is the first to propose to the world. It has long areas. been in development by NHK (the Japanese In view of these developments, it is signifi­ Broadcasting Corporation). The term Hi-Vision cant that a book that systematically deals with itself is becoming well-known worldwide. Hi-Vision technologies is being published. Until NHK has been involved in the research and now there has not been any publication that ad­ development of a high-definition television sys­ equately dealt with Hi-Vision technologies, and tem for almost twenty years. Over this period, students and engineers interested in the subject the project has moved from basic visual, audi­ have had to sift through numerous journals and tory and psychological research to the devel­ papers. opment of experimental and broadcast quality Believing that there was now a need to sys­ equipment. With practical implementation near tematically present the results of a quarter cen­ at hand, a considerable amount of equipment is tury of research and development, the NHK Sci­ now already on the market. Furthermore, efforts ence and Technical Research Laboratories decided are underway to commercialize the technology to compile this volume. Each section has been by improving the performance of household and written by the research staff members directly broadcast systems and establishing an interna­ involved in the project and knowledgeable in tional standard. the latest developments.