Motorola Corporation

Osamu Saionji

Masami Aiura

A vertical contour correcting circuit that provides contour correction of a luminance signal at a horizontal color transition area of an image, thereby minimizing dot interference at the color transition area of a reproduced image. The vertical contour correcting circuit includes a vertical band-pass filter which outputs a level difference signal. The level difference signal is delayed to produce a first delay signal. The first delay signal is delayed to produce a second delay signal. An intermediate value signal is determined from the level difference signal, the first delay signal, and the second delay signal. The intermediate value signal and the first delay signal are added together so that their carrier color signal band components are canceled out.

Contour correction signal generating circuit

A method of determining a chrominance element for pixel signals of an optical image for a 1H delay circuit. The pixel signal(s) are first filtered through a band-pass filter to remove low frequency luminance components and a part of the filtered signal is fed through a 1H scan line delay. The result is a OH pixel signal and a 1H pixel signal one scan line apart. The OH pixel signal is added to the 1H pixel signal to generate a combed chrominance component, and the OH pixel signal and the combed chrominance component are compared to see which is the greater. If the value of the OH pixel signal is greater or equal to the combed chrominance component, the combed chrominance component is output as the chrominance element. If the value of the OH pixel signal is less than the combed chrominance component, the OH pixel signal is output as the chrominance element.

Advanced comb filter

A circuit that separates a luminance signal and a color signal so that dot interference in a color transition area of a reproduced image is minimized. A color video signal is transmitted to an adaptive bandpass filter via a vertical carrier color signal extraction filter. An output signal from the adaptive bandpass filter represents the color signal portion of the color video signal. The color signal is subtracted from the color video signal via a subtractor circuit to produce the luminance signal portion of the color video signal. Since the output signal of the bandpass filter is subtracted from the color video signal, the luminance signal portion of the color video signal is separated without being affected by different colors before and after a color transition point.

Growing community of inventors

Ibaraki, Japan

Osamu Saionji