Estimating the Directions to Light Sources Using Images of Eye for Reconstructing 3D Human Face

Abstract

This paper proposes a technique to estimate the direction of light sources based on the image of eye where the light source is imaged as reflection. The estimated directions of light sources are used to reconstruct 3D shape of face based on the photometric stereo technique. By using the reconstructed 3D shape, we can reproduce faces under various illuminants and from various viewing points. Without knowing the standing position of the subject, we can estimate the directions of light sources on human face from there images of eye for three light sources. In the process of this estimation, it is assumed that human eye is the sphere, and the geometrical constrains for reflection are used in the imaging system. The position and the size of human eye are also estimated as a result of the process. Since the standing position of the subject taken is not restricted in capturing the images, our imaging system is very practical to be used. The effectiveness of the proposed techniques are demonstrated by experiments.