Reflectance and light source position estimation from a sparse set of images

In this paper, we present a new method to estimate the surface reflectance property of an object, as well as the position of a light source. The proposed method allows spatial variation in the diffuse reflectance while assuming that the specular reflectance remains constant. Given a 3D geometric model of an object with specular reflection and a small set of images from a single view as input, our method simultaneously recovers the reflectance property and the light source position by using an iterative separating-fitting technique. We estimate the light source position by firstly fitting the reflectance property to the Lambertian model and then fitting the reflectance property to a more complex reflection model while separating the specular and diffuse components iteratively. By estimating the object's reflectance property and the light source position, we can freely render the object under arbitrary lighting conditions. Experimental results show the accuracy of our estimation method.