Apparatus and method for improving the signal-to-noise ratio of video display signals

摘要

An apparatus and method for continuously improving the signal-to-noise ratio of a stationary video image by digital integration, without the loss of signal amplitude incurred by conventional designs. The apparatus includes a sampling analog-to-digital converter for digitizing an input video signal frame which is supplied to a calculating device along with a preceding video signal frame supplied from the output of the calculating device through a memory device. These features, in conjunction with other digital logic components, form a digital recusive filter. The calculating device sums new and previously stored data for each pixel in amounts scaled to counteract the loss of signal range that occurs as the random-noise component averages to zero. By appropriate selection of operating parameters, the method can be used to maintain or even boost the amplitude of a video signal while simultaneously enhancing its signal-to-noise ratio.