Shape from shading base on finite-element

This paper uses an algorithm to shape from shading based on finite-element. According to finite-element principle, a smooth surface can be approximated by a group of triangular patches. The brightness of this triangular patch can be computed using reflectance map. This brightness can be regarded as the approximate brightness of the corresponding triangular area. With a linearized reflectance map, a square of brightness error function can be made. Then the result of minimizing the brightness error function is the corresponding surface height. The experiments on synthetic and real images show that the algorithm is very efficiency and accuracy.