A quaternion phase-only correlation algorithm for color images

Due to mathematical limitations, conventional phase-only correlation (POC) technique can only be applied to grayscale images or at most complex images. A full color image must be first converted to a grayscale one before performing the POC, during which the chrominance information has been wasted. In this paper, a novel extension of the POC technique to the quaternion field (QPOC) is proposed, which can naturally make full use of the luminance as well as the chrominance information in color images. The effectiveness of the proposed QPOC for color images is demonstrated through its applications in color template matching and subpixel color image registration.