Image analysis of gunshot residue on entry wounds - I - The technique and preliminary study

An automated image analysis (IA) technique has been developed to obtain a m easure of the amount (i.e. number and area) of gunshot residue (GSR) partic les within and around a gunshot wound. Sample preparation and IA procedures were standardised to improve the reproducibility of the IA measurements of GSR. Measurements of GSR from test firings into goat hide were enhanced by staining the barium and lead components present on the skin sections with Alizarin Red S. The amount of GSR detected on the stained skin sections was compared with backscatter electron micrographs of the same sections. The d ifferences were deemed to be insignificant when the variability in the repe ated test firings were taken into consideration. Preliminary results indica ted that the decreasing relationship between firing range and the amount of GSR deposited was non-linear, and that for firing ranges of up to 20 cm th e amount of GSR deposited from repeated shots fired from the same distance was highly variable. (C) 1999 Elsevier Science Ireland Ltd. All rights rese rved.