Quaternion Fourier–Mellin moments for color images

The quaternion Fourier–Mellin moments for describing color images are introduced, which can be seen as the generalization of traditional Fourier–Mellin moments for gray-level images. Then, the quaternion Fourier–Mellin moment invariants are derived, which could be a useful tool in color object recognition tasks that require the similarity invariance. In addition, the problem of color image registration using quaternion Fourier–Mellin moments is discussed. The registration method can match color images differing in rotation and scaling. The advantage of our method is that it can process color image directly, without losing color information. Experimental results validate the effectiveness of the method we proposed.