Surface topography using shape-from-shading

This paper demonstrates how a recently reported shape-from-shading scheme c an be used to extract topographic information from 2D intensity imagery (Wo rthington and Hancock, IEEE Trans. Pattern Anal. Mach. Intell. 21 (1999) 12 50-1267). The shape-From-shading scheme has two important features which en hance the recovered surface description. Firstly, it uses a geometric updat e procedure which allows the image irradiance equation to be satisfied as a hard constraint, This not only improves the data closeness of the recovere d needle map, but also removes the necessity for extensive parameter tuning . Secondly, we use curvature information to impose topographic constraints on the recovered needle map. The topographic information is captured using the shape index of Koenderink and van Doorn (Image Vision Comput. 10 (1992) 557-565) and consistency is imposed using a robust error function. We show that the new shape-from-shading scheme leads to a meaningful topographic l abelling of 3D surface structures. Moreover, the resulting topographic info rmation proves to be useful in a simple histogram-based object recognition scheme. (C) 2001 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.