1. A method of identifying a portion of a digital image corresponding to an object, the method comprising: deriving an initial object indication mask based on pixel-wise differences between a first digital image and a second digital image, at least one of which includes the object; performing an edge finding operation on both the first and second digital images, wherein the edge finding operation includes: determining whether pixel-wise differences in edge strength between the first digital image and the second digital image exceed a pre-determined edge strength threshold and pixel-wise differences in edge direction between the first digital image and the second digital image exceed a pre-determined edge direction threshold; and marking at least one added edge, wherein the at least one added edge includes any pixel determined to have an edge strength difference exceeding the pre-determined edge strength threshold and an edge direction difference exceeding the pre-determined edge direction threshold; generating a plurality of straight linear runs of pixels across an image containing the object, wherein each of the plurality of straight linear runs starts and ends on an added edge and is contained within the initial object indication mask; and forming a final object indication mask by retaining only pixels that are part of at least one of the plurality of straight linear runs.