Unit for and method of video signal enhancement and image display apparatus provided with such a video signal enhancement unit

摘要

A video signal enhancement unit ( 100 ) and an image display apparatus containing the unit have a processing unit ( 102 ) for contrast modification of the video signal. The processing unit ( 102 ) receives input data from a contrast counter ( 112 ), designed to store a contrast count. The contrast count is decreased by a pixel counter ( 104 ) each time the total number of pixels which have video signal levels that are higher than a predetermined video level, exceeds a predefined threshold. The contrast count is increased each time a trigger means ( 114 ) generates a pulse. A contrast comparator ( 116 ) can be coupled to the contrast counter ( 112 ) to limit the contrast count to a maximum contrast value.