3D-spline reconstruction using shape from shading: Spline from shading

In this work, we describe an original method of solving the shape from shading (SFS) problem, which relies on the marriage of two simple ideas. On the one hand, we propose to modelize the scene by a parametric surface, namely a 3D-spline. The key advantage is that boundary conditions are no longer required to render the problem well-posed. On the other hand, we introduce the concept of ‘‘useful domain’’: this is a sufficient set of pixels, whose greylevels are in accordance with the SFS hypotheses, which allows to solve the SFS problem on the whole reconstruction domain. The proposed method is described for both formulations of SFS, corresponding to orthographic and perspective projections. We can thus validate our method on synthetic as well as on real images. 2007 Elsevier B.V. All rights reserved.