Date of Award
Master of Science in Optical Science and Engineering
Department of Engineering Physics
Samuel D Butler, PhD.
The bidirectional reflectance distribution function (BRDF) describes realistic scattering of light off materials by relating incident irradiance to outbound radiance. One popular class of BRDF models assumes a surface is comprised of tiny microfacets. The drawback of microfacet BRDFs is that they often no not contain specific material parameters and neglect wavelength effects. Wave optics BRDF expressions, however, can describe wavelength effects at the expense of being more computationally cumbersome. Previous work of following a Beckmann-Kirchhoff derivation of BRDF, then relating wave optics BRDF coordinates to microfacet coordinates led to a complicated, but versatile, BRDF. In this work, the infinite summation found via this derivation is investigated. This involves algebraic simplification of the expression inside the infinite summation and curve fitting to find a functional approximation to this summation. Some methods which may accomplish this are detailed. The relationships between a wave optics and microfacet BRDF are expected to eventually lead to a simple closed-form BRDF model that more accurately describes wavelength-dependent effects and which will be fast enough to be usable in remote sensing applications.
DTIC Accession Number
Freda, Samuel E., "Microfacet Wavelength Scaling of the BRDF" (2016). Theses and Dissertations. 461.