Kazuo Ishikura

A Motion-Adaptive High-Definition Converter for NTSC Color TV Signals

In a conventional NTSC monitor, such impairments as cross-color, cross-luminance, line flicker, and line crawl limit both picture quality and resolution. A newly developed high-resolution converter removes impairments caused by composite, interlaced scanning signals. It includes two new processing circuits. The input NTSC signal is decoded into component signals by a new motion-adaptive YC separator. Then, the component signals are converted into a sequential scanning format by a new motion-adaptive scan line interpolator. By utilizing these two kinds of motion-adaptive processing, the impairments mentioned above are reduced considerably.

High Quality Digital TV With Frame Store Processing

Though the existing TV standard (NTSC) is a highly sophisticated method to transmit a color television signal without a wide frequency bandwidth, it has some intrinsic problems as follows. (1) Cross-luminance (hanging dots) and cross-color interferences These are caused by the incompleteness of a luminance/ chrominance separation. Hanging dots interference is caused by the cross talk of the chrominance signal into the luminance signal. On the contrary, the cross-color interference is caused by the cross talk of the luminance signal into the chrominance signal. (2) Line flickering and coarse scanning line structure These are caused by interlace scanning. Line flickering is very obvious at the edge where the image changes its brightness in the vertical direction. The coarse scanning line structure can be observed in motion pictures very well because they have only 262.5 scanning lines a field.

Study on signal processing for progressive-interlace scan conversion using a progressive TV camera.

現行インタレース走査系の画質妨害の低減について, 順次走査カメラの信号を使用した順次-インタレース走査変換の信号処理により可能な機能を検討した.まず, 走査を垂直・時間周波数領域での標本化の観点から3次元周波数解析を行い, インタレース折り返し歪みの除去, 時間周波数30Hzの動きの処理, 垂直補強信号による解像度向上などが, 順次走査カメラの導入によって初めて実現可能になることを明らかにした.次に, 時空間フィルタに垂直方向フィルタを使用して, 動解像度特性を損なうことなくこれらの機能を実現する具体的な走査変換の手法を検討した.そして, 試作装置を用いた評価実験により有効性を検証した.