A model for visual camouflage breaking

Abstract

Some animals use counter-shadingin order to prevent their detection by predators. Counter-shadingmeans that the albedo of the animal is such that its image has a flat intensity function rather than a convex intensity function. This implies that there might exist predators who can detect 3D objects based on the convexity of the intensity function. In this paper, we suggest a mathematical model which describes a possible explanation of this detection ability. We demonstrate the effectiveness of convexity based camouflage breakingusingan operator (“Darg”) for detection of 3D convex or concave graylevels. Its high robustness and the biological motivation make Darg particularly suitable for camouflage breaking. As will be demonstrated, the operator is able to break very strong camouflage, which might delude even human viewers. Beingnon-edg e-based, the performance of the operator is juxtaposed with that of a representative edge-based operator in the task of camouflage breaking. Better performance is achieved by Darg for both animal and military camouflage breaking.