Digital display devices, which include liquid crystal display (LCD), LCD projection, liquid crystal on silicon (LCoS), plasma display panel (PDP), etc., tend to lack details in the dark areas or dark scenes of the displayed image. More particularly, digital displays are limited in their overall grey levels making it difficult to show shades of grey. For example, an 8 bit resolution display is limited to a maximum of 256 levels. Because of this limitation, the grey levels in the dark area are usually hard to distinguish.
Generally, traditional histogram equalization can be used to enhance the picture quality, but not without drawbacks. With traditional histogram equalization, the entire picture is affected, including, unnecessarily, the bright area of the picture. As a result, the noise level tends to increase and the computing load tends to be quite heavy in real time video. It may cause motion artifacts and picture flash because of the heavy computing loads associated with histogram equalization. Hence others have turned to simple gamma correction, which requires less computing time than histogram equalization, to improve the digital display. Consumers, however, remain unsatisfied with the results of these correction methods.
Therefore, it would be desirable to provide a system and method that enhances the picture quality in the dark areas of an image on a digital display.