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Shape from shading: using several images

A different way to constrain the image irradiance equation: add another one.

Photometric stereo: use more images; same viewing direction, different illumination conditions (e.g., time of day).

Varying the direction of illumination changes the reflectance map R. Suppose we measure for two illumination conditions. We get two equations for :

The intersection of the isophotes in p,q-space determines the surface orientation at .

Edelman Shimon
Wed Oct 18 09:18:18 EDT 1995