A new TV system which transmits signals multiplexed by the quadrature modulation of a picture carrier is under development. Since hue jitter is caused by the quadrature modulation, there is the previously reported problem of compatibility with NTSC. In this paper, an analysis of the production mechanism of the hue jitter is presented. Hue jitter becomes more pronounced as the ratio of multiplexed signal level to picture carrier level modulated by luminance signal gets higher and as the frequency of the multiplexed signal gets lower. Hue jitter is reduced by narrowing the band width of the carrier reduction circuit in a TV set using syncronous detection. Based on this analysis, hue jitter reduction methods decreasing the multiplexed signal level and decreasing the lower frequency area of a multiplexed signal are proposed.

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A new high speed and flexible interactive color image quantization method is proposed in this paper. Methods have been developed for color image quantization into over 256 levels. These methods, however, can not provide effective color quantization into the much smaller numbers (i. e., 8 or 16) of levels, nor flexible color selection reflecting a designer's feelings. The proposed method is intended to overcome there two problems using one selection parameter (D). This parameter D represents a maximum distance between representative and candidate color points in the R G B space. With smaller D-value, impressive color even in a smaller area can be preserved. With larger D-value, subtle color change can be expressed. An efficient multi-dimensional data structure, BD-tree, is introduced to realize high-speed and flexible quantization. Experiments with many standard color images reveal the flexibibility and superiority of the proposed method.

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The visual space range of the image in a stereoscopic picture is important in evaluating a 3D image system. The visual space range is determined by both the system condition and fusional limits of the binocular parallax. First, this paper derives the relationship between the fusional limits of the binocular parallax and the depth of the reproduced image. Second, the limits are measured using a stereo-HDTV with two 40-inch CRTs and a one OHP-type stereoscopic picture with newly developed STEPOgraphy. Fusional limits are not affected by viewing distances greater than 1.5m in these results. Limits increase at a rate of about 10 arc minutes per arc degree of the stereoscopic picture viewing angle for uncrossed binocular parallax, and at a rate of about 5 arc minutes for crossed binocular parallax. At nearer distances, the effect with the viewing angle of the stereoscopic picture decreases. The viewing angle of the picture and the viewing distance satisfied with fusional limits are considered.

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[in Japanese]

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