초록 ▼

A method for registering a pattern image with a reference image is provided. The pattern image and the reference image differ from each other by a Rotation-Scale-Translation (RST) transformation defined by a scale factor s, a rotation factor .phi., and a translation vector (.DELTA.x, .DELTA.y). A Fo

A method for registering a pattern image with a reference image is provided. The pattern image and the reference image differ from each other by a Rotation-Scale-Translation (RST) transformation defined by a scale factor s, a rotation factor .phi., and a translation vector (.DELTA.x, .DELTA.y). A Fourier-Mellin invariant is used to perform image registration by isolating the rotation, scale and transformation parameters of the RST transformation between the reference image r and the pattern image p.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method for registering a pattern image with a reference image, wherein the pattern image and the reference image differ from each other by a Rotation-Scale-Translation transformation defined by a scale factor s, a rotation factor .phi., and a translation vector (.DELT

[ What is claimed is:] [1.]1. A method for registering a pattern image with a reference image, wherein the pattern image and the reference image differ from each other by a Rotation-Scale-Translation transformation defined by a scale factor s, a rotation factor .phi., and a translation vector (.DELTA.x, .DELTA.y), the method comprising:(a) preprocessing the reference image and the pattern image, including the steps of:(a-1) transforming the reference image and the pattern image from a pixel domain to a Fourier-Mellin domain to provide a transformed reference and a transformed pattern, respectively; and(a-2) converting the transformed reference and the transformed pattern from Cartesian (x, y) coordinates to polar-log (log.sub.B (radius), angle) coordinates, where B is a global constant logarithm base;(b) recovering at least one potential scale factor, including the steps of:(b-1) summing the polar-log (log.sub.B (radius), angle) reference and the polar-log (log.sub.B (radius), angle) pattern along the angle axis thereof to provide a reference scale signature and a pattern scale signature, respectively;(b-2) correlating the reference scale signature with the pattern scale signature using a normalized correlation to provide a correlated scale signature;(b-3) detecting local maxima of the correlated scale signature which comprise a set of scale signature shifts; and(b-4) raising the logarithm base B to the power of each scale signature shift to provide the at least one potential scale factor;(c) recovering the rotation factor .phi., including the steps of:(c-1) summing the polar-log (log.sub.B (radius), angle) reference and the polar-log (log.sub.B (radius), angle) pattern along the log.sub.B (radius) axis thereof to provide a reference rotation signature and a pattern rotation signature, respectively;(c-2) correlating the reference rotation signature with the pattern rotation signature using a normalized circular correlation to provide a correlated rotation signature; and(c-3) detecting the maximum value of the correlated rotation signature which comprises the rotation factor .phi.; and(d) recovering the scale factor s and the translation vector (.DELTA.x, .DELTA.y), including the steps of:(d-1) rotating the pattern image by -.phi. to provide a rotated pattern;(d-2) for each potential scale factor, resealing the rotated pattern by the inverse of the potential scale factor to provide a candidate pattern;(d-3) for each candidate pattern, determining a potential translation vector which, when the candidate pattern is translated by the potential translation vector, produces the highest correlation between the reference image and the translated candidate pattern; and(d-4) selecting the translated candidate pattern which produces the highest correlation with the reference image, whereby the potential scale factor and the potential translation vector associated with the selected candidate pattern comprise the actual scale factor s and the actual translation vector (.DELTA.x, .DELTA.y), respectively.