A set of reference images is being developed by ISO/Tc130 working Group 2 to form an International Standard for graphic arts use. This set referred to If as SCID (Standard Color Image Data). The SCID will be available in an electronic form on CD (Compact Optical Disk) and will provide a common set of visual reference materials for evaluation of image processing, data transfer, data compression, proofing, press machine and output devices. This paper introduces the outline of SCID and statistics of SCID.

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We already proposed the hierarchical storage techniques using magnetic disks and an optical mass storage system (MSS) that was applied to the video-on-demand systems. In this paper, we propose the new video data copying techniques from the MSS to the magnetic disk(or RAM) when the video program is requested. And the new video playback techniques for visual search are proposed. (1)Frame allocation for a fast-forward and backward playback with multiple access. (2) various kinds of fast-forward and backward playback techniques. (3)Audio-playback techniques in case of fast-forward playback and skip-search playback. (4)Skip-search playback techniques. (5)Backward skip-search playback techniques.

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JPEG for standard coding method of still image is based on DCT. However. DCT has block distortion and mosquito noise. In this paper, we describe an error image coding method by split i image using wavelet transform.

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Bi-directional prediction scheme has been adopted by MPEG as a standardized coding technique. Hitherto, the one directional prediction scheme, which employs temporally pre-frame alone, has been widely used. Recently, the bi-directional prediction scheme, which uses both temporally pre and post frames, is also utilized. It is generally known that the bi-directional prediction is effective with respect to the coding efficiency. However, the effectiveness has yet to be examined through subjective picture quality assessment. we conducted a subjective assessment test of the decoded picture quality using HDTV sequences. The results show that the bi-directional prediction scheme works Well on most of the sequences with respect to picture quality improvement, but causes flickers to some sequences.

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In the digital broadcasting, channel hopping recovery time would be an important issue to be ad-dressed. The recovery time depend on the interval of intra refresh, and can be shortened by adopting more frequent, refresh, which would degrade coding efficiency in turn. To investigate into this subject, coding simulations were carried out, to study relationship between refresh interval and coding efficiency. Moreover. subjective assessment tests, in which some kind of channel hopping conditions with different recovery time were evaluated, were performed to obtain an accept,able channel hopping time. These results will benefit to introduce appropriate digital broadcasting systems.

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"The 2nd generation EDTV (EDTV-2)" will be standardized in Japan in 1995. It is a 16:9 wide-screen TV format and maintains NTSC compatibility. We have developed 1 an experimental EDTV-2 decoder and the software EDTV-2 encoder. A digital audio decoder for EDTV-2 was also developed.

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In this paper, we will make clear about the problems in applying Motion Compensated DCT coding scheme to EDTV-II signals, considering the case where EDTV-II signal is transmitted via existing TV links with digital compression. In the main panel signal of EDTV-II, because the horizontal high frequency signal is modulated and inserted to vacant frequency bands (the holes), the entropy increases under the MC-DCT scheme, in which the interframe prediction error of the DCT coefficients corresponding to the hole have signiflcant power.

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The azimuth recording is essential for a guard-band-less recording which is employed in tape recording systems using rotary-heads such as digital VTR, R-DAT. The performance taken account of azimuth recording characteristic for Partial Response Maximum Likelihood (PRML) systems are evaluated by the required SNR to achieve a bit error rate of 10^<-4> obtained by computer simulation.

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