The effect of weave orientation on the BRDF of tarp samples

The results of bi-directional reflectance distribution function (BRDF) measurements of four tarp samples obtained from NASA's Stennis Space Center (SSC) are presented. The measurements were performed in the Diffuser Calibration Facility (DCaF) at NASA's Goddard Space Flight Center (GSFC). The samples are of similar material structure but different reflectance. The experimental data were obtained with a Xe arc lamp/monochromator light source as well as laser light sources in the ultraviolet, visible, and near infrared spectral regions. The BRDF data were recorded at four incident zenith angles and at five incident azimuth angles. The dependence of the measured BRDF on weave orientation was analyzed and presented. 8 degree directional/hemispherical reflectance data were also measured for each tarp sample, and those results are also reported. All results are NIST traceable through calibrated standard plates. The specular and diffuse scatter data obtained from these studies are used by NASA's SSC in their field-based, vicarious calibration of satellite and airborne remote sensing instruments.