Structured Surface BRDF Reciprocity: Theory and Counterexamples

Definition and invariance properties of structured surface BRDF

The bidirectional reflectance distribution function (BRDF) is used to characterize the directional properties of surface reflectance, but the most recent standardized definition fails to address some important aspects for the structured and varying surfaces encountered in remote sensing. This article proposes an updated definition of BRDF that is applicable for such surfaces. The updated defini...

An Inexpensive BRDF Model for Physically-Based Rendering

A new BRDF model is presented which can be viewed as an kind of intermediary model between empirism and theory. Main results of physics are observed (energy conservation, reciprocity rule, microfacet theory) and numerous phenomena involved in light reeection are accounted for, in a physically plausible way (incoherent and coherent reeection, spectrum modiications, anisotropy, self-shadowing, mu...

Reciprocity of the bidirectional reflectance distribution function (BRDF) in measurements and models of structured surfaces

Surface Registration with a Helmholtz Reciprocity Image Pair

This paper introduces a novel surface model registration technique based on the Helmholtz reciprocity principle. Initially, a 3D surface model is generated for an object of interest. Two images of the object are then acquired under controlled lighting conditions. Given one of the images and an estimate of the surface pose, Helmholtz reciprocity is used to predict the appearance of the object su...

Four-parameter model for polarization-resolved rough-surface BRDF.

A modeling procedure is demonstrated, which allows representation of polarization-resolved BRDF data using only four parameters: the real and imaginary parts of an effective refractive index with an added parameter taking grazing incidence absorption into account and an angular-scattering parameter determined from the BRDF measurement of a chosen angle of incidence, preferably close to normal i...