A Stereoscopic Scanner System for Behind Armor Debris

In response to an Army need for a data collection tool that can measure the velocities of Behind Armor Debris (BAD) fragments in controlled experiments, we propose to develop a Stereoscopic Scanner System (S3) that employs four digital streak cameras to record stereoscopic streak images of debris fragments as they pass through two parallel streak planes. Unlike conventional high-speed cameras, which produce two-dimensional photographs at moments in time, a streak camera produces a photograph where time is one of the dimensions. A unique property of streak photography that makes it ideal for this application is that objects in the debris field are naturally sorted by velocity. In Phase 1, we built a breadboard scanner system using line-scan cameras operating at 20 kHz, and used this system to obtain streak photographs of debris fields with velocities up to 90 m/s. These experiments helped to establish requirements for the system such as camera line rate and field-of-view, illumination intensity and wavelength, and optimum camera configuration for stereo viewing. In Phase 2, we will build and deliver a prototype scanner system using high-speed Digital Streak Cameras that will be capable of measuring fragments with velocities up to 1000 m/s.