We present a generalisation of the 4-light photometric stereo technique to an arbitrary number Q of illuminants. We assume that the surface reflectance can be approximated by the Lambertian model plus a reflectance component. The algorithm works in a recursive manner eliminating the pixel intensities affected by shadows or highlights based on a least squares error technique, retaining only the information coming from illumination directions that can be used for photometric stereo reconstruction

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... of the normal of the corresponding surface patch. We report results for both simulated and real surfaces and compare them with the results of other state of the art photometric stereo algorithms.