Patent ID: 7408591

Claim:
A method for extracting an alpha matte from a video acquired of a scene, comprising the steps of: acquiring a set of narrow aperture images I P of a scene with a first camera aperture set to a relatively large depth-of-field and a narrow aperture, the scene including a background B and a foreground F, and in which each narrow aperture image I P is expressed as I P =αF+(1−α)B, where αF is an image in front of a background image B, and α is an alpha matte; acquiring a corresponding set of wide aperture images I F of the scene with a second camera aperture set to a relatively small depth-of-field and a wide aperture, and in which each wide aperture image I F is expressed as I F =αF+(1−α)B F , where B F =B{circle around (×)}h B , and h B is a point spread function; and extracting an alpha matte according to α=C+(I F −I P )/(B−B F ), where C is a constant.