A contrast correction device for correcting a contrast of an image formed by video signals includes a brightness/darkness detecting circuit for detecting a tone level of the image and for producing a bright signal when the tone level is greater than a predetermined brightness, and a dark signal when...http://www.google.com/patents/US5196937?utm_source=gb-gplus-sharePatent US5196937 - Contrast correction device for correcting video signal contrast by varying luminance signal
