The Prediction and Measurement of the Optical Properties of Complex Surfaces

Determining the optical properties of complex surfaces for signature analysis can be problematic.  Materials with surface structures, e.g, crinkled or patterned foil appliques, or striated or ribbed surfaces will produce a non-isotropic BRDF, which can be difficult to measure and represent in signature models. This paper will describe an analytical approach to predicting the optical properties of these surfaces. The calculations use a ray tracing algorithm and faceted model of the surface structure, materials and bulk optical properties. A comparison to measurements from the SOC 210 Bidirectional Reflectometer is presented. Also, the challenges of potential parameterized approaches for inclusion in signature models are discussed.