A subpixel color image registration algorithm using quaternion phase-only correlation

In this paper, we extend the conventional phase-only correlation (POC) technique to the quaternion field (QPOC) and propose a subpixel color image registration algorithm based on the QPOC. Due to mathematical limitations, traditional POC-based registration algorithms can only be applied to grayscale images or at most complex images. A color image must be first converted to a grayscale one before performing the POC, during which the chrominance information has been wasted. The proposed algorithm not only can naturally make full use of the luminance as well as the chrominance information in color images, but also can directly estimate the subpixel translational shift from the 2D data array of the QPOC function. Experimental results have shown the effectiveness of our algorithm.