Image registration using log-polar transform and phase correlation

Registration is the process of finding transformations that makes correspondence between related image pairs so that pixels in the two images precisely coincide to the same points in the scene. Once registered, the image can be combined or fused in a way that improves useful information extraction. The log-polar transform (LPT) is a well known space variant image registration scheme used for medical images. However though LPT is invariant to rotation and scale changes, it does not support translation faithfully. In this paper, a hybrid algorithm for image registration that produces faithful mapping under affine geometrical distortion using LPT, Fourier transform (FT), and phase correlation has been presented. The resultant algorithm is invariant to rotation, scale and translation. The proposed algorithm is verified on medical images with affine shifting, partial data, and in the presence of noise.