UDC 004.932: 519.64
FREQUENCY METHOD OF FILTERING PERIODIC INTERFERENCE
OF DIGITAL IMAGES
A. I. Novikov, Dr. Sc. (Tech.), associate Professor department of higher mathematics, RSREU, Ryazan, Russia;
orcid.org/0000-0002-8166-8234, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
A. V. Pronkin, post-graduate student of the Department of electronic computing machines, RSREU, Ryazan, Russia;
orcid.org/0000-0003-2832-7462, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
N. O. Shamin, student RSREU, Ryazan, Russia;
orcid.org/0000-0001-9175-9095, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
The aim of the work is to develop and experimentally test a method for filtering periodic interference of
a digital image based on two-dimensional discrete Fourier transform (DFT). Periodic interference in the
image in the form of rectilinear bands, or in the form of lines of a more complex structure, but at the same
time periodic, corresponds to the local maxima of the amplitude spectrum obtained as a result of performing
direct DFT. To filter periodic interference, it is necessary to detect local maxima, reset Fourier coefficients
in the vicinity of local maxima and apply inverse DFT to a modified matrix of Fourier coefficients. A simple
method for detecting local maxima on amplitude spectrum and an approximate method for forming regions
of zeroing the Fourier coefficients in the vicinity of local maxima are proposed. Studies of the results of filtering
periodic interference of various shapes, intensities and, in particular, in conditions of additive discrete
white noise have been carried out.
Key words: periodic interference, filtering, discrete Fourier transform, amplitude spectrum, local extremum,
estimation of mathematical expectation