Normal map recovery using bundle adjustment

Although modern reconstruction methods have advanced considerably, their ability to retrieve fine details, small features of a surface is limited. Applying texture can be used to conceal lack of geometry to some extent, but it becomes apparent when lighting varies. A more sophisticated solution is to map normal vectors to the surface of the model in order to alter the way it is rendered under different illuminations in accordance with the properties of the real object. The principle of photometric stereo is to reconstruct normals from a series of images. By illuminating the object with different directional light sources local surface orientation can be inferred. The contribution of this study is that the authors successfully applied the widely used bundle adjustment algorithm to photometric stereo problems when non-parallel light rays illuminate the objects.