Patent ID: 6219450
Filing Date: 2001-04-17
Classification: G06T,H04N

Abstract:
A method for determining a grid location within an image wherein P(i,j) is the light intensity of image pixels at position (i,j) in the image, comprising the steps of:(a) computing a first set of R sums E.sub.H of absolute values of differences in a horizontal direction including only samples which are a predetermined pixels R apart wherein D.sub.H is equal to values in a range from 0 to R -1 and ##EQU6##(b) computing a second set of R sums E.sub.V of absolute values of differences in a vertical direction including only samples which are a predetermined pixels R apart wherein D.sub.H is equal to values in a range from 0 to R-1 and ##EQU7##(c) determining if the image contains a grid based on a relationship between the first and second sums and a predetermined threshold; and(d) locating a boundary in the grid as a point vertically shifted by D.sub.V pixels from an origin and horizontally shifted by D.sub.H pixels from the origin, wherein D.sub.v and D.sub.H are values which maximize E.sub.V and E.sub.H, respectively.