Methods for finding and characterizing a deformed pattern in an image

Abstract

A method is disclosed for finding a deformed pattern in an image using a plurality of sub-patterns. By advantageously restricting sub-pattern search ranges, search speed is improved, and the incidence of spurious matches is reduced. The method also quickly decides which sub-pattern result, of several potential candidates, is most likely to be the correct match for a deformed sub-pattern. Also, a method is provided for characterizing a deformed pattern in an image by using results from feature-based search tools to create a mapping that models the deformation of the pattern. A transform, selectable by a user, is fit to the results from the search tools to create a global deformation mapping. This transformation is fit only to feature points derived from matches resulting from successful sub-pattern search, without including data from areas of the pattern that were blank, not matched, or otherwise didn't contain information about the pattern's distorted location.

1 . A method for finding a deformed pattern in an image, the method comprising:
 providing a plurality of features that represent the deformed pattern in the image;   dividing the plurality of features into a pluralities of sub-pluralities, each sub-plurality representing a sub-pattern in the image, a plurality of the sub-patterns representing the deformed pattern;   determining a distance between each pair of sub-patterns of the plurality of sub-pluralities;   selecting a first sub-pattern to locate in the image;   locating the first sub-pattern in the image so as to provide a first sub-pattern location;   using the first sub-pattern location to select a second sub-pattern to locate in the image;   locating the second sub-pattern in the image so as to provide a second sub-pattern location; and   using the first sub-pattern location and the second sub-pattern location to determine a location of the deformed pattern.   
     
     
         2 .- 47 . (canceled)