digital images

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.

The Comparison of Digital Images of Firing Pin with a Dominant Features in the Form of Circles and Arcs

Introduction. Development of the algorithms for the automatic comparison of the digital images of firing pin is an important task of the forensic examination. This task is aimed at improving the efficiency of crime investigation involving the use of firearms. In this paper images of firing pin with the features in the form of circles and arcs with single center are investigated. The method based on modified Euclidean distance between circles of the similar firing pin was proposed to assess the degree of similarity of the traces. Preliminary processing. To eliminate the adverse effect of noise and various image artifacts were pretreated. Markers were placed to accurately determine the features in the form of circles. Method of searching paired tracks. Criteria based on modified Euclidean distance were developed for the formation of the priority list. Numerical experiment. In the numerical experiment database of 60 objects was used. Paired trace from firing pin array was included in top four of the prior list in 90 percent cases. Conclusions. The proposed algorithm allows to sort effectively and quickly the array of test objects by the degree of similarity of signs in the form of arcs and circles with relevant features of the test track.