This automated measuring device obtains spectral data from various azimuth and elevation angles around a specific object to generate a bidirectional reflectance distribution function (BRDF) so that scientists can better understand, view, and predict the physical location of the object if it were in orbit with Earth. Simply put, objects look different when viewed from different angles and when illuminated from different directions. BRDF is the technical, objective measure of reflectance and illumination that causes those different views and is a critical step in space situational awareness (SSA), which involves tracking objects in orbit with Earth. The space community is seeking more efficient approaches for BRDF characterization due to increasing space debris and launches of small satellites. Available devices for BRDF are based on a fixed item and a mobile camera taking images from different elevation angles, which does not efficiently calculate a BRDF. Researchers at the University of Florida have developed a device that uses fixed multiple cameras coupled with a rotary table for moving the item with respect to the camera, thus reducing the time required for complete imaging of an object and increasing the overall productivity of BRDF measurements.
Automated generation of BRDF measurements
This BRDF measuring device consists of spectroscopes attached to a rigid structure that defines the angle and elevation for each spectroscope. The object of interest is placed on a turntable illuminated by a xenon arc lamp, and it is incrementally rotated to the desired azimuth angles to attain accurate spectral measurements. These measurements are recorded at every azimuth angle and processed to calculate the BRDF. A BRDF describes how much light is reflected when light makes contact with a certain material and is a critical step in determining how the object will behave and interact in space. This device increases productivity and provides a new approach for scientists to quickly learn the BRDF of any object.