Abstract: An improved method and apparatus for color correction normalizes two of the three color signals as a function of the third. In the preferred embodiment, an image comprising red, green and blue (RGB) signals are converted to a luminance Y signal, a saturation signal and a hue signal. The luminance and saturation signals are normalized as a function of hue. In the most preferred embodiment, for all fully saturated colors, the luminance values are normalized to a value of 0.5, and the saturation values to unity for all values of hue. The normalized values of saturation and luminance are utilized with the hue value in a secondary color corrector. The color corrected values of saturation and luminance are denormalized as a function of color corrected hue. Optionally, the color corrected luminance, saturation and hue may be converted to RGB signals for output. In one aspect of this invention, the normalized luminance signal is not used for relatively small values of saturation.

Abstract: Noise in a video picture is sharply reduced using the redundancy of information present in those portions of the picture which remain unchanged through several successive frames. A number of successive frames are compared to determine which portions of the picture are in motion and which are stationary. The moving portions of the image are separated from the stationary portions and are processed in a conventional manner. The stationary portions, however, are combined on a frame-by-frame basis to produce a highly noise-free averaged signal. In color systems, the conventional luminance-chroma separation methods used for the moving portions of the picture are replaced, in the stationary portions, by an opposite-phase frame comparison method which provides 100% separation regardless of the nature of the image.