A Model for Visual Camouflage Breaking

Abstract

Some animals use counter-shadingin order to prevent their detection by predators. Counter-shading means 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 breaking using an operator (“D _arg ”) for detection of 3D convex or concave graylevels. Its high robustness and the biological motivation make D _arg 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 D _arg for both animal and military camouflage breaking.

Supported by the Minerva Minkowski center for geometry, and by grant from the Israel Academy of Science for Geometric Computing.