“Spectro-polarimetric remote surface-orientation measurement”, F.J. Iannarilli, Jr., US Patent 6,678,632 (issued 13 January 2004).

A measurement technique enabling single-viewpoint (monocular), single-frame (snapshot) passive 3D imaging.

To perform a passive monocular remote determination of a surface's three-dimensional orientation, the received radiation's polarization state is measured at several wavelengths in the neighborhood of a resonance in the target surface's refractive index. The distinctive spectral behavior of the complex refractive index across a resonance feature causes the Fresnel component of reflectance to manifest Stokes spectral radiance patterns that change characteristically with angle of incidence. Furthermore, these patterns are self-normalizable, thus yielding an orientation inference that is robust to most sources of nuisance variability.