traces on bullets

Compensation of Distortions of Images of Traces on the Deformed Bullets for their Automated Comparison

Introduction. The purpose of work is: a research of ability of compensation of distortions caused by deformation of bullets. Theoretical analysis. In work examined bullets with deformation in the type of local annular expansion. This type of deformation is basis for compensation of complex distortions. Nodal point method selected for the evaluation of image distortion and compensation. Model experiment. Model of deformed 9 mm bullet obtained in 1:50 scale for determination of transformation coefficients. The table of transformation coefficients obtained by means of experiments for different diameter variations. Experimental studies. Experiments have been carried out for bullets, the shot from a Makarov pistol caliber 9 mm. The overlapping of images of non-deformed and deformed bullet showed before converting divergence of paired attributes in brinks images. Distortions of trace images on the deformed bullet compensated. Coinciding traces overlapped almost completely. Conclusions. The algorithm compensation of distortions of deformed bullets images develop. This system approved for symmetric deformation. The algorithm can be used for compensation of distortions of traces images on the deformed bullets.

The Concept of Mathematical Model of the Assessment of Uniqueness of Sets of Coinciding Routes in Secondary Traces on the Shot Bullets

Introduction. The model of an assessment of probability of casual combination of sets of routes in secondary traces is considered in article. Development of quantitative criteria of justification of a categorical positive conclusion about criminalistic identity of the compared traces, and also algorithm of formation in the automatic mode of the priority list is the purpose of the conducted research. Theoretical part. Twodimensional images of traces of rifling fields used for the simulation. The formulas for estimating the probability of an accidental match of trails were obtained. Experimental part. Calculations performed on the developed formulas, the dependence of the probability of an event compared to the number of trails should be shown. Conclusion. The theoretical possibility of estimating the probability of a random alignment sets of trails (the degree of matching features unique complexes) and its use in practice is shown in this paper.