Preliminary results to define an active multispectral imager for gunshot residues patterns visualization

In incidents involving gunshot wounds, for short range target shooting only, gunshot residues (GSR) are projected on the target and a distinct pattern around the bullet entrance hole may be observed by the forensic experts. A careful analysis of this pattern is often carried out in order to determine the muzzle-to-target distance and angle, and draw some conclusions about the nature of the firearm. However, seeing and recording gunshot residue patterns can be difficult especially if the victim´s clothing is dark. The main goal of our study is to develop a multispectral laser imaging device able to reveal gunshot residue patterns on many kinds of clothes, which provide a fast result. The first stage before developing this device is to acquire and analyze hyperspectral images taken on samples in order to select the best spectral bands to use and to develop the appropriate processing to enhance the pattern.