Patent ID: 8483489

Claim:
A method for image processing comprising: (a) determining edge pixels of a model image using an edge based technique; (b) determining an angular orientation for each said edge pixels of said model image; (c) determining a lower spatial resolution model image based upon said model image and determining respective angular orientations for said lower spatial resolution model image; (d) determining edge pixels of an input image using an edge based technique; (e) determining an angular orientation for each of said edge pixels of said input image; (f) determining a lower spatial resolution input image based upon said input image and determining respective angular orientations for said lower spatial resolution input image; (g) matching said lower spatial resolution model image with said lower spatial resolution input image to determine candidate locations of an object within said input image; (h) based upon said candidate locations matching said input image with said model image; (i) wherein said image processing further includes at least one of: wherein said matching is performed at a plurality of different scales without storing additional model images; wherein results of said matching are further utilized to determine a fractional pixel object position of said model image and to determine a fractional object rotation angle of said model image; wherein said matching skips candidate positions of said input image based upon a previous filtering of said input image to determine areas of said input image that contain a sufficient number of edge pixels; wherein said matching is also based upon searching a limited range of angles based upon objects identified in said model image having rotational symmetry; wherein said matching is also based upon searching a set of angles determined by adaptively selecting an angle sampling interval based upon an object of said model image; wherein said matching is also based upon searching a set of angles determined by analyzing auto-correlation of said model image across rotation angles; wherein said matching of said lower spatial resolution model image and said low spatial resolution input image is based upon both a position search and an angle search, and further including at least one refinement stage matching a higher spatial resolution model image and a higher spatial resolution input image based upon both a higher resolution position search and a higher resolution angle search.