Yoshimichi Ohtsuka

An HDTV Broadcasting System Utilizing a Bandwidth Compression Technique-MUSE

An HDTV broadcasting service on one satellite broadcast channel became available after the development of a transmission system called MUSE involving bandwidth compression. Using MUSE, a satellite channel of width 27 or 24 MHz in the 12 GHz band can carry an HDTV picture, digitally-coded four-channel sound and independent digital signal at about 100 Kb/s.

A Motion-Compensated Interframe Coding Scheme for Television Pictures

A motion-compensated prediction system for interframe coding is proposed. An interframe coding system is developed using this prediction method and second-order temporal prediction. Realtime hardware of reasonable circuit size using this coding system for monochrome TV pictures has been constructed. Sampling frequency and bit-rate of this system are 10.06 MHz and 1.6 bits/pel, respectively. Assessments have been made of the picture quality of coded/ decoded pictures from a variety of broadcast television programs. Quality was good for almost all such programs. A subjective test of picture quality was performed under stringent conditions, using some of the most difficult scenes selected in earlier experiments. The lowest value for the quality of pictures coded/ decoded at 1.6 bits/pel was 3.7 on a five-grade impairment scale.

A Motion-Compensated Interframe Coding Scheme for NTSC Color Television Signals

A motion-compensated interframe coding system for an NTSC color television signal has been developed. The output of a local decoder is used in the form of a Y/C separated signal. Motion vectors are detected using the Y signal, and the Y signal and both baseband components of the C signal are motion-compensated. The motion-compensated signals are reencoded into an NTSC signal to provide a motion-compensation interframe prediction in the NTSC format. Real-time experimental hardware has been built. The sampling frequency and bit rate of this system are 10.7 MHz and 1.6 bits/ sample, respectively. This value includes all overhead information such as motion vectors and other control information. An assessment has been made of the picture quality of coded/decoded pictures taken from a variety of broadcast television programs. The quality was good for almost all the programs. A subjective test of picture quality was performed under stringent conditigns. The lowest value for the picture quality of the most difficult scenes at 1.6 bits/sample was 3.3 on a five-grade impairment scale.

A motion-compensated noise reducer.

フレーム間符号化等ですでに開発されている動き補正技術を応用した動き補正型ノイズリデューサについて述べる.ノイズリデューサのフレームメモリーの出力信号に動き補正を加えることにより, 現入力信号とそれ以前の信号との間の位置ずれをなくすことができる.したがって, 動き補正型ノイズリデューサにおいては, 従来型のノイズリデューサで問題になっていた, 動きエッジ部の動きぼけあるいはノイズの残留等を防ぐことができ, 良好な画質を得ることができる.動き補正フレーム間符号化の実験装置を改修することにより, 実時間で動作する動き補正型ノイズリデューサの実験機を製作した.その結果, 動き補正をノイズリデューサに導入することの有効性が確かめられた.なお, 実用装置を製作する場合の従来方式のノイズリデューサに比べた回路規模の増大はわずかである.

Television Flicker Eliminator for Lighting by a Fluorescent Lamp

商用電源周波数が50Hzの地域では螢光灯等の照明下において撮像するとフリッカーを生ずる.これは特に中継等において重大な妨害となっているが, 後処理によって除去する方式を開発し, 装置を試作した.この原理は, この種のフリッカーが20Hzであることに着目し, 映像信号中よりフリッカー成分を抽出し, これで映像信号に逆変調を加えることでフリッカーの除去を行うものであり, 動画像に対しても副次的な画質劣化を伴うことなく有効に動作する.試作装置を実際に中継の現場で使用した結果, その有効性が確かめられた.