Patent ID: 6278798
Filing Date: 2001-08-21
Classification: G06K

Abstract:
A method of model-based image recognition, comprising the steps of:(a) extracting image points from an input two-dimensional image;(b) selecting a set of n of said image points extracted in step (a) and a set of n model points of a three-dimensional model in a class of K models, where n is a positive integer greater than or equal to 4 and K is a positive integer;(c) computing a transformation of three dimensions to two dimensions based on said set of n model points and said set of n image points, said transformation a matrix C=JW.sup.T (WW.sup.T).sup.-1 where J is a 3.times.n matrix with each of the columns of J defined by a scaling factor plus the scaled two coordinates of one of said n points in said image and W is a 4.times.n matrix with each of the columns of W defined by a constant plus the three coordinates of one of said n points in said model;(d) repeating steps (b)-(c) for all sets of n of said image points and all sets of n model points of a model of said class of models;(e) selecting a hypothesized transformation from said transformations created by steps (b)-(d) wherein said hypothesized transformation is characterized by an error measured by CW-J of less than a predetermined threshold, but when none of said transformations has an error less than said predetermined threshold, selecting no transformation; and(f) indicating recognition of an object in said image and corresponding to the model including the n model points of said hypothesized transformation when a hypothesized transformation is selected in step (e), else indicating no model objects recognized in said image when no transformation is selected in step (e).