A method for mapping an object (28) includes illuminating the object with at least two beams (37, 38) of radiation having different beam characteristics. At least one image of the object is captured under illumination with each of the at least two beams. The at least one image is processed to detect local differences in an intensity of the illumination cast on the object by the at least two beams, and the local differences are analyzed in order to generate a three-dimensional (3D) map of the object.