METHOD FOR SELECTING IMAGES FOR IDENTIFICATION OF WEAPON FROM STRIKER TRACE Russian patent published in 2016 - IPC F42B35/00 

FIELD: weapons and ammunition.

SUBSTANCE: invention relates to identification of firearms from traces of striker with individual feature spot of arbitrary shape by processing digital images of traces of strikers and their further analysis. Investigated shell is scanned to produce original digital image of investigated striker trace in grayscale. Local variations of gradations are smoothed. Smoothed initial digital image of striker trace is converted into binary black-and-white image, in which background has one colour, and individual attribute of other. Individual feature descriptors are measured, which do not depend on orientation of image, represented by area S perimeter P, maximum I_max and minimum I_min moments of inertia. Method includes selecting similar images of striker trace with individual feature in form of spot of arbitrary shape from database of trace images. From traces selected from image database, sampling images of traces with closest values of descriptors S, P, I_max, I_min. Method includes presenting a loop of individual attribute of analysed trace and traces, selected from trace image database in form of N standard complex vectors. Finding magnitude of normalised scalar product of loop of analysed trace with loops selected from a database of traces. For identification of firearm, selecting from a database of images of traces with greatest value of maximum magnitude of normalised scalar product of loops.

EFFECT: higher efficiency of formation of priority of a list of images based on degree of similarity thereof with analysed trace by eliminating effect of orientation of images on comparison result, as well as accelerated selection of images based on degree of similarity thereof with the analysed by simplifying calculations.

2 cl, 7 dwg, 9 tbl