An Automatic Alignment Procedure for a 4-Source Photometric Stereo Technique applied to Scanning Electron Microscopy

This paper presents an automatic alignment procedure for a 4-source photometric stereo technique to reconstruct the depth map in the scanning electron microscopy. PS, based on the so-called reflectance map, used several images of a surface to estimate the surface depth at each image point. Lambertian reflectivity function is the simplest one. In the SEM one of the most important signals, the backscattered electron emission, is nearly Lambertian, and, to simplify matters, SEM images are intrinsically grey scale maps. The possibility for electron-PS is assumed, taking advantage of one of the most exciting features of the technique, which doesn´t return some depth illusion from ordinary pictures, but true numerical 3D models