Orientation Correlation

A new method of translational image registration is presented: orientation correlation. The method is fast, exhaustive, statistically robust, and illumination invariant. No existing method has all of these properties. A modification that is particularly well suited to matching images of differing modalities, squared orientation correlation, is also given. Orientation correlation works by correlating orientation images. Each pixel in a orientation image is a complex number that represents the orientation of intensity gradient. This representation is invariant to illumination change. Angles of gradient orientation are matched. Andrews robust kernel function is applied to angle differences. Through the use of correlation the method is exhaustive. The method is fast as the correlation can be computed using Fast Fourier Transforms.