METHOD FOR AUTOMATIC REGION SEGMENTATION ON CARTRIDGE CASE BASE AND SELECTION OF THE BEST MARK REGION FOR CARTRIDGE CASE COMPARISON

摘要

Segmentation of certain regions defined on a firearm cartridge case for successful automatic matching of cartridge cases after a cartridge is fired, on the basis of the marks left on the cartridge cases fired. Disclosed is a method for segmentation of a cartridge case base by using surface height matrix information comprising; detecting the center of the cartridge case base; according to this center, obtaining the polar height matrix by subjecting the surface height matrix to polar transformation; acquiring a one-dimensional signal, "Average Height Signal on Basis Radius (AHSBR), by calculation of the mean value on the radius axis applied on the polar height matrix; determining regions similar to circle signal models on the AHSBR and detecting circles; determining the firing pin mark region by threshold processing of the primer region surface height matrix. Letters on the cartridge case base are detected by using slope matrices.