Unsupervised Color Film Restoration Using Adaptive Color Equalization

Chemical processing of celluloid based cinematic film, becomes unstable with time, unless they are stored at low temperatures. Some defects, such as bleaching on color movies, are difficult to solve using photochemical restoration methods. In these cases, a digital restoration tool can be a very convenient solution. Unfortunately, for old movies color and dynamic range digital restoration is usually dependent on the skill of trained technicians who are able to control the parameters through color adjustment, and may be different for a sequence or group of frames. This leads to a long and frustrating restoration process. As an alternative solution, we present in this paper, an innovative technique based on a model of human color perception:, to correct color and dynamic range with no need of user supervision and with a very limited number of parameters. The method is combined with a technique that is able to split the movie into different shots and to select representative frames (key frames) from each shot. By default, key frames are used to set the color correction method parameters that are then applied to the whole shot. Due to the robustness of the color correction method the setting used for the key frame is used successfully for all the frames of the same shot.