Disclosed herein is an image processor including: a depth image acquisition portion adapted to acquire a depth image for an image frame making up the movie, the depth image representing, as a pixel value on an image plane, a subject distance from an imaging device; an edge extraction portion adapted to generate an edge image for the image frame and identify a picture area of a tracked target in the depth image on the basis of an outline of the tracked target represented by tracking results for the image frame at a previous time so as to extract an edge in an area limited on the basis of the picture area; and a tracking section adapted to compare the extracted edge against an outline candidate for the tracked target to find a likelihood so as to estimate the outline of the tracked target and output the outline as tracking results.