Вісник Черкаського державного технологічного університету (Oct 2019)

IMPROVEMENT OF THE METHOD FOR IDENTIFYING OF CLONING RESULTS IN A DIGITAL IMAGE

  • Володимир Олексійович Хорошко,
  • Іван Ігорович Бобок

DOI
https://doi.org/10.24025/2306-4412.3.2019.177317
Journal volume & issue
Vol. 0, no. 3
pp. 38 – 49

Abstract

Read online

Cloning remains one of the most common tools used for unauthorized changes to digital images. Cloning is implemented in all modern graphic editors. Many experts in the field of information security are engaged in solving the problem of cloning detection, but this task has no final solution to date. A modification of the method for identifying cloning results in a digital image is proposed in the paper. The effectiveness of this method exceeds the efficiency of modern analogues. It remains effective when the cloned image is subjected to additional disturbing influences. These disturbing influences do not differ for the clone and prototype. Also, the method is effective when the size of the clone / prototype is small. The purpose of the modification of the method is to ensure its effectiveness under the conditions of certain geometric transformations to which the clone is subjected. These transformations are: reflection relative to the vertical and/or horizontal axis, rotation through an angle multiple of 90°, reflection relative to the diagonal (main, secondary) of the corresponding matrix. In this paper, the principle of constructing a matrix of minimal block differences is changing. This matrix is mapped to a digital image. It is the main subject of research in the method. The element of the matrix of minimal block differences reflects the smallest difference of a particular block from any other block of the image. The difference between the blocks is calculated as the difference of their singular spectra. The singular spectrum of the matrix does not change during the geometric transformation. Advanced method has high efficiency. A value of TRP = 100 % indicates that when the method is running, skip-ping of cloned images does not occur. The improved method is also effective in identifying several clones that correspond to one prototype. Several clones experience different geometric transfor-mations.

Keywords