207 Development of a New method for Inspection of Metallic Surface Defects

In metallic surfaces, highlights are very strong and light shape is often observed as a specular reflection. A number of methods have been proposed to remove or reduce specular reflection components of inhomogeneous objects and quite a few methods are applied to metallic surfaces. This paper presents a method that can reduce specular reflection components of metallic surfaces. A set of real images are taken in various lighting conditions and Photometric Linearization method is introduced to control diffuse reflection components as well as reducing specular reflection components. It separates specular reflection components and converts input images to imaginary images that contain only diffuse reflection components. The experimental results show that specular reflection components can be effectively reduced in realistic images of metallic surfaces using this technique.