The Evolution of TV
 

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HI-Vision (HDTV):
Pursuit of large-screen, high-definition TV system


1964   Research on high-definition TV begins at STRL
1969 First exhibition of high-definition TV study at STRL Open House
1970 NHK determines provisional standards of 1125 scanning lines, 5:3 aspect ratio
1971 Research on a discharge display (PDP) begins
1975 Development of a 3-tube wide display (100 cm wide, 50cm high, 1125 scanning lines)
1981 Test manufacture of 1-inch tape VCR for high-definition TV
1983 Development of MUSE system, compression and transmission system for HDTV
1985 The name Hi-Vision (HDTV) given to the system
In 1964, the engineers of NHK who had done a TV relay broadcast from the Tokyo Olympic Games using their independently developed technology, were groping with the problem of a “future television.” This future TV was eventually symbolized by a large-screen, high-definition TV set. However, the realization of this dream would be many years in the making, beginning with basic studies on human audio-visual physics.

1964 16:9 Ratio Derived from Research on Human Audio-visual Characteristics

Pursuit of Future Television
The Tokyo Olympic Games in 1964 made a strong impression on the public and demonstrated that the level of TV technology in Japan was the highest in the world. Those in TV related industries in Japan were envisioning the next generation of TV. STRL initiated studies on high-definition television (HDTV) in 1964.
Research followed two tracks. One was to visualize “future TV” from a thorough investigation of what was to be expected of the future television system, as well as the physical conditions of the system. The other approach was to reexamine the kind of display, or video, to determine the easiest and most desirable media for humans to watch. This involved a thorough study of human audio-visual characteristics and psychology. Among a number of options, STRL decided on high-definition TV as the main direction for its research, calling it simply HDTV. In 1985, this system was named Hi-Vision.

16:9 Ratio Derived from Human Audio-visual Characteristics
Regarding the ratio between height and width of the display, the aspect ratio, evaluations made using a slide projector revealed that the most desirable aspect ratios are 5:3 or 6:3, wider than the 4:3 ratio then used for a standard TV display. Later, the aspect ratio 16:9 was decided upon, in consideration of its compatibility with movies.
From 1965 to 1975, advances were made in determining the necessary number of scanning lines for HDTV. During this time, the decision to go with an interlaced scanning system was also made. These involved both film simulations and actual TV systems.

Developments in Imaging, Recording, Transmission, and Displays
STRL determined NHK’s provisional studio standard for HDTV around 1970. This standard was 1125 scanning lines, a 2:1 interlaced ratio, and a 5:3 aspect ratio. Based on this standard, work was initiated on imaging systems, recording devices, transmission systems, and large-screen display PDPs.
In 1969, the first experimental high-definition TV system was exhibited at the STRL Open House. It used a 1.5-inch vidicon and a 27-inch black-and-white Braun tube. For an image pickup tube, a 2-inch return beam Saticon was also developed.
STRL began the development of a color camera system around 1970, resulting in a small, low power consumption, 2/3-inch Saticon camera in 1985, and a high-sensitivity high-definition TV camera with a 2/3-inch HARP (High-gain Avalanche Rushing amorphous Photoconductor) tube in 1988, which made capturing images outdoors at night feasible. In 1998, an HDTV camera using a HARP tube was produced on a commercial basis.

1. HDTV and audio-visual properties
2. Exhibition in the United States (1981)


System used in experiments to investigate the relationship between viewing angle and sense of reality.
This system measures a wide-field induced effect by projecting various visual images onto a semi-spherical dome (wide-field induced effect: a phenomenon that causes a viewer to subconsciously lean their body in a certain direction when an inclined wide-field image, such as an image containing a horizon, is projected).


26-inch high-definition TV (combined 3 Braun tubes)


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