Edge detection on color images using RGB vector angles

Abstract

This paper introduces a new edge detection approach for color images. The method is based on the calculation of the vector angle between two adjacent pixels. Unlike Euclidean distance in RGB space, the vector angle distinguishes differences in chromaticity, independent of luminance or intensity. It is particularly well suited to applications where differences in illumination are irrelevant. Both metrics were implemented as modified Roberts edge operators to determine their effectiveness on an artificial image. The Euclidean method found edges across both luminance and chromatic boundaries whereas the vector angle method detected only chromatic differences.