US Patent 7362361 Noise suppressing circuit using luminance detection

A technique of achieving optimal noise suppression with respect to a video signal whose noise amount differs according to brightness is disclosed, and according to the technique, a low-luminance detecting section 18 detects a video signal of a relatively low luminance, a suppression amount setting section 19 generates a noise suppression amount which becomes larger as the luminance of the video signal becomes lower, and a noise suppressing circuit 17 suppresses noise with the noise suppression amount generated by the suppression amount setting section with respect to the video signal of a relatively low luminance detected by the low-luminance detecting section.