Patent ID: 7228006

Claim:
A method for detecting a geometrically transformed copy of content in at least a portion of an image, said method comprising the steps of: providing first and second digital images; locating one or more objects of interest within each said digital image; identifying pairs of corresponding said objects of interest in the digital images, wherein each pair of corresponding objects of interest comprises a located object of interest in the first digital image and a corresponding located object of interest in the second digital image that corresponds to the located object of interest in the first image; locating feature points on each located object of interest in each digital image; matching feature points on the located object of interest in the first digital image to the feature points on the corresponding object of interest in the second digital image, thereby generating a set of correspondence points for each image; choosing one of a predetermined plurality of geometric transformations to provide a chosen tranformation, said transformations having different numbers of parameters, said choosing being based on relative numbers of said parameters in respective said transformations and said correspondence points in said set; determining parameters of said chosen transformation that relate the set of correspondence points in the first digital image into the set of correspondence points in the second digital image; transforming the first digital image according to the parameters of the determined geometric transformation; and detecting regions of similarity between the content of the transformed first digital image and the second digital image, thereby determining if the second image contains a region that is a geometrically transformed copy of a region in the first image.