Efficient mask expansion for green-screen keying using color distributions.

Masks are heavily used in image and video processing, particularly in the context of green screen keying. Designing good masks is a difficult task that involves painting over small details of images. Usually, only a rough mask is created. We propose an algorithm to expand such a mask, using color similarity. Our approach is fast, even on 4K images, and compares favorably with standard tools used in keying.