Theoretical Analysis of Scanning Electron Microscopes with Plural Detectors as an Application Field of Photometric Stereo

Surface topography measurement methods using SEM with plural detectors are analyzed as an application field * . of photometric stereo. Plural-detector methods use images from several detectors. These images correspond to ordinary images made with the light source in different positions. SEMs are usually treated as a field for application of shape from shading, but we shodld consider that detector positions also affect the image intensities or shadings. Photometric stereo can therefore be applied to SEM especially with plural detectors. This study shows experimental results and then gives some theoretical analyses needed to get high-resolution results. Exact rather than empirical formulas are given for calculating inclination angle from the data gathered by twoand four-detector SEM systems. An approach to eliminating the shadow distortion effect is shown.