A preserving color space transformation for correlation between two images using FFT

We propose an efficient method for detecting similarities between two color images. It is based on an extension of a phase correlation method. As this latter is defined only for monochrome images, we develop here a reliable transformation method of color images to monochrome ones. The most remarkable property of this transformation compared to the classical ones is its ability to transform a color image to monochrome image without a loss of information on colors. Furthermore using the proposed transformation, the phase correlation technique can measure the similarities between two color images, and offers a high degree of accuracy and robustness at no extra cost.