Alpha channel estimation in high resolution images and image sequences

Abstract

For motion picture special effects, it is often necessary to take a source image of an actor, segment the actor from the unwanted background, and then composite over a new background. The standard approach requires the unwanted background to be a blue screen. While this technique is capable of handling areas where the foreground blends into the background, the physical requirements present many practical problems. This paper presents an algorithm that requires minimal human interaction to segment motion picture resolution images and image sequences. We show that it can be used not only to segment badly lit or noisy blue screen images, but also to segment actors where the background is more varied.