Perspective Shape from Shading with Non-Lambertian Reflectance

In this work, we extend the applicability of perspective Shape from Shading to images incorporating non-Lambertian surfaces. To this end, we derive a new model inspired by the perspective model for Lambertian surfaces recently studied by Prados et al. and the Phong reflection model incorporating ambient, diffuse and specular components. Besides the detailed description of the modeling process, we propose an efficient and stable semi-implicit numerical realisation of the resulting Hamilton-Jacobi equation. Numerical experiments on both synthetic and simple real-world images show the benefits of our new model: While computational times stay modest, a large qualitative gain can be achieved.