The present invention provides a method for the calculation of a pattern similarity metric that is locally normalized with respect to illumination intensity, and is invariant with respect to rigid body preserving gray scale variations, such as scale, rotation, translation, and non-linear intensity transformations....http://www.google.es/patents/US6154567?utm_source=gb-gplus-sharePatente US6154567 - Pattern similarity metric for image search, registration, and comparison
Pattern similarity metric for image search, registration, and comparison
