Active Thermography for Gunshot Residue (GSR) Pattern Estimation on Textiles

Gunshot residue (GSR) analysis on textiles plays a crucial role in forensic investigations. These residues vary in size and shape depending on the shooting distance; this relationship is evaluated by testing a new methodology of textile observation using active thermography. By integrating active infrared (IR) thermography with image processing techniques, the contrast between gunpowder particles and the cloth background is enhanced, facilitating reliable detection and analysis. The observed infrared emission patterns provide insights into the behavior and the distribution of gunpowder dispersion, aiding in determining the shooting distance. The analysis of GSR dispersion on the cloth reveals the presence of an increasing trend in the relationship between the shooting distance and the distance from which gunshot residue was detected, demonstrating the effectiveness of active thermography in detecting gunshot residue patterns up to a firing distance of about 30 cm. Beyond this distance, the signal-to-noise ratio decreases significantly, presenting problems in accurately identifying the presence of residues. The advantages of active thermography are underlined, including its non-intrusive and non-destructive nature and the elimination of the necessity for chemical reagents, simplifying the analysis process as potential tool for determining shooting distance.