Chrominance Edge Preserving Grayscale Transformation with Approximate First Principal Component for Color Edge Detection

Abstract

Edges that are visible in color images may not be detected in the corresponding grayscale image. This is due to the neighboring objects having different hues but the same intensities. Hence, a color edge preserving grayscale conversion algorithm is proposed that helps detect color edges using only the luminance component. The algorithm calculates an approximation to the first principal component to form a new set of luminance coefficients instead of using the conventional luminance coefficients. This method can be directly applied to all existing grayscale edge detectors for color edge detection. Processing only one channel instead of three channels results in lower computational complexity compared to other color edge detectors. Experimental results on test images show similar edge detection capabilities to typical color edge detectors at reduced complexity levels.