Abstract: An image enhancement system in which a running average of a group of digitized samples of a video signal and a median of a group of digitized samples are processed to form a gradient sample. The gradient sample is scaled in response to the noise level of the video signal. The gradient samples, average samples, and medium samples are combined by a processor which generates a corresponding sequence of output samples that are converted into an enhanced video signal from which an image is produced. The processor provides image edge enhancement for high gradients while providing increased noise filtering for low gradients.

Abstract: A noise reduction filter for a television receiver in which two running averages of video signal amplitude are generated over regions of the video picture where the brightness level is substantially constant. One or the other of the averages is used to control intensity to obtain a reduction of random noise in the video signal. In areas of the picture where rapid changes in intensity occur, the averages are not used in favor of the unmodified video signal.