Colour image edge detection using quaternion quantized localized phase

Recently, a novel edge detection method for gray-level image using quantized localized phase was proposed in [1]. The rationale of this method for edge detection is that we can obtain more edge and contour information of interested image from its quantized localized phase rather than from its magnitude. This is because the phase information is of greater importance on edge areas than on smooth areas. In this paper, we generalize the method in [1] to deal with colour image edge detection using quaternion polar form and two dimensional quaternion short-term Fourier transform (2-D QSTFT). By applying 2-D QSTFT to colour image, locally quantizing the phase part of quaternion polar form of the transformed image, and then reconstructing the resulted image using 2-D QISTFT and quantized phase, we can preserve the edge information and therefore achieve the goal of colour image edge detection.