Template matching in rotated images.

A rotationally invariant template matching using normalized invariant moments is described. It is shown that if normalized invariant moments in circular windows are used, then template matching in rotated images becomes similar to template matching in translated images. A speedup technique based on the idea of two-stage template matching is also described. In this technique, the zeroth-order moment is used in the first stage to determine the likely match positions, and the second and third-order moments are used in the second stage to determine the best match position among the likely ones.