Spline-Based Algorithms For Shape From Shading

Rui J.P. de Figueiredo; Vishal Markandey

doi:10.1117/12.942872

12 March 1988 Spline-Based Algorithms For Shape From Shading

Rui J.P. de Figueiredo, Vishal Markandey

Proceedings Volume 0850, Optics, Illumination, and Image Sensing for Machine Vision II; (1988) https://doi.org/10.1117/12.942872
Event: Advances in Intelligent Robotics Systems, 1987, Cambridge, CA, United States

Abstract

Algorithms to recover the shape of objects from the shading caused by illumination are reported. This constitutes an approach dif-ferent from the variational method using occluding boundaries found in the literature. The latter method determines a surface that satisfies the image irradiance equation as a constrained optimization problem, where occluding boundaries of the object's silhouette provide initial conditions and the image irradiance equation, and smoothness constraints determine an objective function to be minimized. Our technique splits the problem into two subproblems. The first subproblem consists of determining the surface function values on a two-dimensional grid of points from the corresponding image irradiance values that are measured. These points are determined by minimizing the square error between the irradiance values and the surface reflectance at the corresponding points determined from the reflectance map. The second subproblem consists of fitting a two-dimensional spline surface to the surface points computed from the above grid, using smoothing criteria based on appropriate partial different operators. Depending on the criterion chosen, different types of spline fits for the surface may be obtained.

Citation Download Citation

Rui J.P. de Figueiredo and Vishal Markandey "Spline-Based Algorithms For Shape From Shading", Proc. SPIE 0850, Optics, Illumination, and Image Sensing for Machine Vision II, (12 March 1988); https://doi.org/10.1117/12.942872

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