SHAPE INDEX AND POLYNOMIAL COEFFICIENT BASED PATTERN ANALYSIS AND COMPARISON METHOD FOR CARTRIDGE CASES AND BULLETS IN FORENSIC SCIENCE

摘要

Ballistic marks are the striation and impression marks of a firearm imprinted on metallic surfaces of cartridge cases and bullets and their fragments when they are fired from the firearm. Firearm identification is the process of determination of bullets, cartridge cases and their fragments that are fired from the same firearm by examining similarity of ballistic marks. These marks are affected from metal hardness, amount of gun powder, etc. These reasons make automated firearm identification a difficult problem. It is proposed in the present invention that feature comparison based on shape index and polynomial coefficients to determine bullets, cartridge cases and their fragments that are fired from the same firearm. These features can be extracted from surface height map or surface normal vectors using estimation methods.