Experimental evaluation of two criteria for pattern comparison and alignment

Pattern comparison and pattern alignment are related tasks. The former requires the use of a similarity measure for discriminating between patterns of different classes, while the latter requires a measure of the degree of alignment of two similar patterns. This paper presents an experimental evaluation of two promising measures, Fourier phase correlation and mutual information, which can be used for quantifying the similarity as well as the degree of alignment of two patterns. It is shown that these measures are quite stable to a range of pattern intensity variations, while exhibiting gradual monotonic decrease in the presence of geometric transformations. Phase correlation is more resistant to pattern noise and interference, whereas mutual information is more resistant to intensity variations and geometric distortions.