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; measuring variances of intensities along the scan lines in the epipolar image; and extracting an alpha matte according to the variances.