The System Recognizes the Digital Image of Pistol Shell Casings by Developing Algorithms Combined with Deep Learning

Abstract

Gun-related violence in Thailand is in a high rate. Resume reports showed that most of them caused by gun-shooting.Thus, Firearms and bullets are important evidence in the judicial process to link the events and the perpetrators.Therefore, the aim of this study was to present the system recognizes the digital image of pistol shell casings by developing algorithms combined with deep learning. The objectives of this forensic study were to 1) analyze, design, and develop a Pistol Identification System (PIS) based on breech face marks of cartridge case digital images, and 2) achieve a guideline or an alternative method for facilitating an expert to investigate firearms linked to the offender. In this research the PIS that was designed with programming language applied to develop algorithms for identification of the breech face marks of cartridge case digital images. In addition to that, MATLAB’s tools were applied in the deep learning process to achieve the final PIS model. The steps of deep learning technique were composed of designing a training and repeat the experiments over multiple cycles (Epoch) for the purpose of confirming, test and adjust the proportions of the hidden layers until reaching the ratio of 80:10:10 and accomplishing a satisfied averaged accuracy rate. The PIS model was subsequently used for comparison and predict the image pair through database management technology. Materials used in this study were composed of 50,000 images of rear plates of .38 Cartridge case, Camera, Mobile Phone, Computer, MATLAB language and Microsoft Access software. The findings showed that the PIS developed is of satisfactory accuracy capable of accurately matching the pairs of images stored in the database and could also be traced back to the gun used at the scene and gun owners. The results of this study would apply as the alternative or guideline to PIS and even would help forensic practitioners to cross-checking and investigating firearms in relation to the offender.