Active Multispectral Bidirectional Distribution Function Measurement System

Today's highly technical battlefield environment dictates the need for a method of standoff target identification, which reduces risk to personnel and equipment. It is widely known that a given material will react differently to incident radiation than a dissimilar material. Certain materials may respond specularly while others tend to be diffuse. By measuring these responses, materials can be identified by comparison with a known database. One method of building such a database for target recognition is by employing an active multispectral bidirectional reflectance distribution function (BRDF) measurement system. In the following text, such a system is developed and tested using a 1.5m and 2.0m tunable source. The system does not yet meet the desired 1.0m range; however, all major system components with exception to the source are well suited for this entire band. A detailed description of the components used is presented along with recommendations for further research. This particular BRDF measurement system implementation is the direct result of a previous attempt that encountered numerous errors. These errors were primarily attributable to nonlinearities, attenuation, and misalignments in the equipment utilized. Considerable effort was expended in order to reduce these anomalies mainly through component replacement. A comprehensive error analysis is presented for this system along with recommendations for a new system, which should reduce these abnormalities and improve data integrity and collection efficiency.