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An extremely high-resolution image system called the Ultra High Definition TV (UHDTV) system, with more than 4000 scanning lines is being developed by the Japan Broadcasting Corp. (NHK). This system provides audio and video with an acute sense of reality so that viewers feel as if they are actually at the site of the filming. UHDTV cameras, projectors, disk recorders, and three-dimensional sound systems have already been developed. UHDTV programs were demonstrated at the 2005 World Exposition, Aichi, Japan, and the system worked successfully there during the six-month run. This paper presents two aspects of the newly developed UHDTV transmission systems: an optical transmission system with dense wavelength division multiplexing (DWDM) technology for contribution, and a codec system based on MPEG-2 for program distribution. A live transmission of uncompressed material with a 260-km single-mode fiber was also performed. For program distribution, some experiments were conducted at bit rates of 200 to 640 Mbits/sec via experimental satellite transponders or IP networks. These transmission experiments demonstrate the feasibility of using UHDTV in future broadcasting.

HDTV is flourishing in Japan and the U.S., and many other countries including those in Europe are planning to start their own services. Europe is now designing the route map to deploying HDTV. The recent progress in related technologies has accelerated the spread of HDTV throughout the world. In particular, the prospects for the picture format of 1080/50p, 60p are growing. This paper will try to give further insights on the prospects of HDTV. First, it will discuss the visual experience that HDTV gives the viewers in relation to his/her viewing environment. Then it will examine the trends toward 1080/50p, 60p from various perspectives, including flat panel displays, production equipment, coding technologies, HDTV television sets, higher resolution technologies beyond HD, and the trends of rival media.

A system format that optimizes viewer appreciation of Ultrahigh-definition and Wide-screen (UDW) images was investigated ; in particular, the relationships among the screen size, viewing distance (angle), screen aspect ratio, and the number of pixels. A linear relationship was found between the screen size and preferred viewing distance. Comparison of the preference for images with four aspect ratios and with 16:9 aspect ratio showed that the preferred aspect ratio depends on the screen size, not the viewing angle, with about 2:1 most preferred in the home environment. The relationship between the screen size and aspect ratio was thus given by a simple equation. An equation for relating the maximum number of pixels necessary for a UDW system to three parameters (screen size viewing distance, and aspect ratio) was derived using the visual resolution capacity.