[in Japanese]

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[in Japanese]

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[in Japanese]

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Tokyo Institute of Technology has been transmitting TV lectures and TV conferences to both the O-okayama and Nagatsuta campuses through optical fiber cables. In January 1989, the lectures were transmitted using fine-quality HDTV with optical fiber cables in order to make an evaluation.
The factor analysis results show the “quality of the image”, the “atmosphere of the lectures”, the “screen”, and the “sound”.
Compared to the NTSC system, the high-definition system was evaluated based on the purposive differentials of 5% level of significance for the “atmosphere of the lecture”, and 1% level of significance for the “projected quallity of image”. There has not been any specific purposive differential for the “screen” and “sound”.
These results indicate that HDTV is very effective for distance education.

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Hough transform is one of the most stabilized methods for feature extraction from digital images. One of the problems of using Hough transform for practical use is that it requires a lot of memory for the θ-ρ parameter plane. If a very high precision θ or ρ is required, the parameter plane grows very large. In this paper, a method for Hough transform computation without using a parameter plane is proposed and the results of the experiment are shown. By this method, high precision computation can be executed using very little memory.

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A systematic study has been made of a high efficiency color image coding system. First, following two (HVC) signal quantization schemes, which were based on the Munsell Renotation Color Space, were estimated : i) perceptual uniform quantization of color space using color differences and ii) coarse quantization of i) using the color reproduction tolerance. Significant features of (HVC) signal are pointed out. Second, based on the quantized (HVC) signal, a color image coding scheme, which regards local features of image, is discussed. Characterized DPCM-VQ coders were adopted to the contour and the flat part of the image separately, where these two parts were separated into each other using the signal features estimated. A satisfactory tharp quality image was obtained by the coding of entropy : 2.4-2.9 [bits/pixel]. The first step of the systematic research of image coding is discussed in this paper. Solving remaining problems and constructing the Picture Quality Scale will allow rapid development of sophisticated color image coding.

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For terrestrial broadcasting of HDTV, NHK has developed the following three ADTV (Advanced Definition Television) systems : (1) NTSC Compatible MUSE-6 (NCM6), (2) NTSC Compatible MUSE-9 (NCM 9), and (3) Narrow MUSE. The NCM6 system and the NCM9 system are compatibile with the NTSC signal. NCM6 system can transmit two digital audio signals. The DANCE (Differential PCM Audio Near-Instantaneous Compressing and Expanding) method is used for audio signal encoding. The NCM 9 system can transmit four digital audio signals or two high quality digital audio signals. To produce a high quality signal, improvement signals of truncation error and audio baseband width, which are transmitted through the augmentation channel, are added to the DANCE-coded signal. These encoded signals are multiplexed into the horizontal blanking period of video signals.

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[in Japanese]

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[in Japanese]

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