Semi-automatic foreground/background segmentation of motion picture images and image sequences

Abstract

Segmentation of images into foreground (an actor) and background is required for many motion picture special effects. To produce these shots, the unwanted background must be removed so that none of it appears in the final composite shot. The standard approach requires the background to be a blue screen. Systems that are capable of segmenting actors from more natural backgrounds have been proposed, but many of these are not readily adaptable to the resolution involved in motion picture imaging. An algorithm is presented that requires minimal human interaction to segment motion picture resolution images. Results from this algorithm are quantitatively compared with alternative approaches. Adaptations to the algorithm, which enable segmentation even when the foreground is lit from behind, are described. Segmentation of image sequences normally requires manual creation of a separate hint image for each frame of a sequence. An algorithm is presented that generates such hint images automatically, so that only a single input is required for an entire sequence. Results are presented that show that the algorithm successfully generates hint images where an alternative approach fails.