Patent ID: 6633669
Filing Date: 2003-10-14
Classification: G06K,G06T

Abstract:
A method of identifying the position in an image of a plurality of features in a substantially four-side, four-cornered grid of features, each feature having a centroid, comprising:a) obtaining an image; b) identifying the significant features in the image; c) defining centroids for each significant feature; d) placing a first integration line contiguous to a first side of the image at an angle &thgr; to the first side; e) recording the centroid integrated intensity of each feature that has its centroid within a predetermined region on either side of the first integration line; f) stepping the first integration line across the image; g) repeating steps (e) and (f) until the first integration line has crossed at least the portion of the image in which a grid is likely to be found; h) analyzing the recorded integrated intensities to find the slope of the first peak in the integrated intensities recorded for the first integration line; i) repeating steps (d) through (h) for a second integration line at an angle &thgr;+&dgr; to the side of the image, and for a third integration line at an angle &thgr;âˆ’&dgr; to the side of the image; j) determining the difference in the slopes of the first peak in the integrated intensities recorded for the first, second and third integration lines; k) if the difference is within a predetermined tolerance limit, defining the one of the first, second or third integration line having its first peak with the highest slope among the three lines as the closest match, and defining the angle of the first column in the grid to match the angle of the closest match, and the position of the first column in the grid to match the location of the first peak in the integrated intensities for closest match; l) if the difference is not within the predetermined tolerance limit, iterate steps (d) through (l) with varying values of &thgr; and &dgr; until the difference in the slopes is within the predetermined tolerance limit.