1. A method for extracting an alpha matte from images acquired of a scene, comprising the steps of: selecting a depth plane for a foreground in a scene; determining a trimap from a set of images acquired of the scene; constructing an epipolar plane image from the set of images and the trimap, the epipolar plane image including scan lines, and in which the identical scan line from all images of the set are stacked in the epipolar plane image, and a 3D point in the scene corresponds to a particular scan line, and an orientation of the scan line corresponds to a depth of the 3D point in the scene; measuring variances of intensifies along the scan lines in the epipolar image; and extracting an alpha matte according to the variances.