Recovery of shape and surface reflectance of specular object from relative rotation of light source

Abstract

In this paper, we present a method for recovery of shape and surface reflectance of specular object from color images taken with a rotating light source.The image sequence is taken with a fixed camera while the light source is relatively rotating around the axis parallel to the optical axis of the camera. By assuming Lambertian reflectance model for the object surface and the orthographic projection for the camera, we can derive a simple relationship between the body reflectance at every object surface point and the rotating angle of the light source.For adapting specular reflectance that can be represented by Phong's model,we develop the algorithm to extract only body reflectance component which obeys the simple relationship for estimating surface normals and body reflectance component. As a result,the object shape and body reflectance distribution of the object surface can be recovered. In addition to this, reflectance parameters of specularity are also estimated by minimize the fitting error of the specular reflectance model.For demonstrating the effectiveness of the proposed method, we show the shape, body reflectance, and specular reflectance of specular objects, which are successfully recovered by the proposed method.