44.2: Distinguished Paper: Adaptive Contrast Enhancement for Digital Video

This paper describes a new real‐time adaptive contrast enhancement technique for digital video applications. The method is a modified contrast limited histogram equalization based procedure that adapts according to the input video statistics. The method decides whether to increase dynamic range or to light up dark regions of the image. As a result, for dark images, details in dark areas are enhanced without affecting mid and bright pixels. However for images with average brightness, the dynamic range of the scene is increased. It is adaptive and provides a localized contrast enhancement effect which is not possible with traditional contrast stretching/gamma LUT based approaches. Unlike traditional histogram equalization based approaches, the technique described automatically tones down its effects on pictures that are prone to contouring and other artifacts and is able to correctly enhance letter‐boxed as well as full‐screen video.