Measurement and modeling of Bidirectional Reflectance Distribution Function (BRDF) on material surface

Measurement and modeling of Bidirectional Reflectance Distribution Function (BRDF) is made to describe optical scattering characteristics of the material surface. A measurement device of BRDF with the ability to real-time measurement is developed by the micro fiber spectrometer and three-dimensional turntables. The measured spectral range is from visible to near infrared with 2.4 nm wavelength resolution. The measured angular range is 0-360° in azimuth angle and 0-85° in zenith angle with 0.01° angle resolution. BRDF measurement on tinfoil and ceramic tile is made and the measurement error is no more than 6.05%. A six-parameter model of BRDF is built according to material surface characteristics. Based on the simulated annealing algorithm, the model parameters of BRDF are obtained through fitting processing of measured data and the maximal fitting error is 9.94%. The results show that the measuring accuracy of BRDF depends on the precision of measuring platform, the sensitivity of measuring instrument and the stability of illuminating light source, and the modeling accuracy of BRDF is closely related to the measured data and optimization modeling method. The measurement and modeling of BRDF may benefit future optical remote sensing, computer graphics and environmental surveillance.