Optical imaging techniques for ballistics specimens to identify firearms

Characteristic markings on the cartridge and projectile of a bullet are produced when a gun is fired. Over thirty different features within these markings can be distinguished, which in combination produce a “fingerprint” for identification of a firearm. This paper describes an investigation into the development of an imaging system which can store, analyse, retrieve, and match high resolution digital images of cartridge cases. A computerised imaging system for ballistics identification will produce efficiencies in time and personnel, and permit a more precise audit of firearms within a country. The project has produced good quality high resolution digitised images of cartridge cases. The development of the optical system to optimise image quality has been crucial for the image identification phase. By classifying cartridge image attributes, it is possible to store the unique “signatures” of cartridge cases for identification. Appropriate image processing provides the signatures for the image library. The FIREBALL forensic ballistics interactive database incorporates a graphics user interface (GUI) to obtain precise ballistics metrics of cartridge case class characteristics. This project will significantly improve the effectiveness and efficiency of ballistics records and assist the tracing of firearms used in criminal activities by law enforcement agencies