EA026460B1 - Method for analyzing digital images of seal impressions for criminalistic examinations - Google Patents

Abstract

The invention is related to the field of information and measurement systems and is designed for comparison of colour-tone parameters in images of seal and stamp impressions during conduction of criminalistic examinations. The objective of the invention is improvement of accuracy in comparison of images of seal and stamp impressions and provision of the possibility of comparing their colour-tone parameters during criminalistic examinations. Said objective is attained by that in a method for analyzing digital images of seal impressions for criminalistic examinations, two digital images of a reference seal impression and an examined seal impression are produced, a scanning window is formed on the reference impression image and a window with the same coordinates is formed on the examined image, scanning is performed in horizontal direction and in vertical direction, and one image window is rotated relative to the other, the maximum value of two-dimensional normalized correlation function R is determined in different areas of the spectrum (R, G, B) in accordance with the expressionwhere Iis the signal of the reference seal impression; Iis the signal of the examined seal impression; x, yare sizes of scanning window;are average signal values in the first and the second scanning windows, Δx, Δy are horizontal and vertical shifts, respectively, Δφ is rotation angle, n=1, 2; maximum correlation function value is elaborated within one pixel; quantitative indicator Pof coincidence of colour-tone parameters in compared images is calculated in accordance with the expressionwhere Kis the maximum possible correlation function value; Kis the obtained correlation function value.

Description

(51) Ιηΐ. C1. С06К9 / 62 (2006.01) (54) METHOD FOR ANALYSIS OF DIGITAL PRINT IMAGES FOR CRIMINALISTIC EXAMINATIONS (43) 2016.06.30 (96) 2014 / EA / 0112 (ΒΥ) 2014.12.19 (71) (73) Applicant and patent holder:

BELARUSIAN STATE UNIVERSITY (BSU); ESTABLISHMENT OF EDUCATION ACADEMY OF THE MINISTRY OF INTERNAL AFFAIRS OF THE REPUBLIC OF BELARUS (ACADEMY OF THE MINISTRY OF INTERNAL AFFAIRS) (VU) (72) Inventor:

Kozlov Vladimir Leonidovich, Rubis Alexander Sergeevich, Ropot Ruslan Mikhailovich (ΒΥ) (56) υδ-Α-5960112 υδ-Β1-6351550 υδ-Β 1-63 04673 Ki-S1-2528140 Ki-S1-2485443 (57)

Claims (1)

CLAIM A method for analyzing digital images of prints of seals for forensic examinations, which consists in obtaining two digital images of the reference and investigated prints, forming a scanning window on the image of the reference print and a window with the same coordinates on the studied image, scanning horizontally, vertically and rotating one image window relative to another, determining the maximum value of the two-dimensional normalized correlation function K in different parts of the spectrum (K, O, B) in accordance with expression - AHAC + Ah, y + Δν, Δφ) - / ₂ ) £ / „(*, Y) __ __________________- ..._____________________________ γ __y_ x, where f is the signal of the reference print imprint; 1 ₂ - signal of the studied print; x _max , y _max - the size of the scanning window; / A - average signal values in the first and second scan window; Ah, Au - horizontal and vertical shift, respectively; Δφ is the angle of rotation; η = 1, 2; - 3 026460 refining the maximum value of the correlation function within one pixel in accordance with the expression Α (.ν + ίΗ, y + y'A) = (1 - / A) (1 - yk) B (x, 7) + (1 - y'A) /// · /? (X +1, y) + + (1 - / A) y'A · K (x, y + 1) + / y'A ² · A (x + 1, y + 1), where g = 1 / k is the refinement grid step ; k is an integer (k = 5 ... 20); ί, _) are the horizontal and vertical indices of the node, respectively; K (x, y) is the maximum value of the correlation function; K (x + 1, y), K (x, y + 1), K (x + 1, y + 1) are the values of the intensity of the correlation function at the points closest to the maximum; calculating the quantitative indicator P _{with the} coincidence of the color-tone parameters of the compared images in accordance with the expression To η _ ^L max ^e 1-V / where K _max - the maximum possible value of the correlation function; To _x is the obtained value of the correlation function.