Jelena Todorovic

The manuscript conducts a comparative analysis to assess the impact of noise on medical images using a proposed threshold value estimation approach. It applies an innovative method for edge detection on images of varying complexity, considering different noise types and concentrations of noise. Five edges are evaluated on images with low, medium, and high detail levels. This study focuses on medical images from three distinct datasets: retinal images, brain tumor segmentation, and lung segmentation from CT scans. The importance of noise analysis is heightened in medical imaging, as noise can significantly obscure the critical features and potentially lead to misdiagnoses. Images are categorized based on the complexity, providing a multidimensional view of noise’s effect on edge detection. The algorithm utilized the grid search (GS) method and random search with nine values (RS9). The results demonstrate the effectiveness of the proposed approach, especially when using the Canny operator, across diverse noise types and intensities. Laplace operators are most affected by noise, yet significant improvements are observed with the new approach, particularly when using the grid search method. The obtained results are compared with the most popular techniques for edge detection using deep learning like AlexNet, ResNet, VGGNet, MobileNetv2, and Inceptionv3. The paper presents the results via graphs and edge images, along with a detailed analysis of each operator’s performance with noisy images using the proposed approach.

The paper analyzed the received ѕignal in the FЅO communication ѕyѕtem, which waѕ modeled by the Gamma-Gamma diѕtribution. Average bit error rate (ABER) valueѕ were calculated for the caѕe when the ѕignal waѕ modulated by BPЅK, DPЅK, OOK, POLЅK and MPPM modulation ѕchemeѕ. Baѕed on analytical expreѕѕionѕ, numerical reѕultѕ are given in the form of graphѕ, where the dependence of ABER on variouѕ parameterѕ of the communication FЅO channel can be determined baѕed on the behavior of the graph.

The paper discusses the operation of wireless sensor networks consisting of nodes based on the IEEE 802.15.4 ZigBee transceiver operating in the presence of Rayleigh or Nakagami-m fading, additive white Gaussian noise (AWGN) and interference. Analytical expressions for bit error rate (BER) for the IEEE 802.15.4 network were obtained when Rayleigh and Nakagami-m fading were processed with a selection-combining (SC) and maximum-ratio-combining (MRC) combiner and when AWGN and interference were present. Analytical results are presented graphically in the form of BER change, depending on the signal-to-noise ratio (SNR) for different values of network parameters: fading parameter (m), number of branches of MRC combiner (L), modulation parameter (M), and spreading sequence lengths (L_c). Graphical results are presented for the system when there are no combiners and when the SC and MRC combiners are included. Numerical results were confirmed by Monte Carlo simulation. Analysis of the SC and MRC combiner application impact on the performance improvement of the IEEE 802.15.4 network and the received signal was performed.

This work deals with the structure of TV channels that are distributed from satellite positions where DTH platforms offer their services in European countries. The structure is being considered via service availability (FTA and PAY TV), resolution (SDTV, HDTV and UHDTV), standards of broadcasting (DVB-S and DVB-S2), satellites and satellite positions, as well as market share of leading satellite operators at European market through which DTH providers do their services to the ultimate users. We also represent the market of TV channel distribution through the number of household which use cable, satellite, terrestrial and IPTV. Collected data are represented as a table and graph for the period from 1996 to 2020.

In this paper, the Average Bit Error Rate of the signal in the Free Space Optical system modulated with On-Off keying scheme is calculated and analysed. The Average Bit Error Rate is determined in the case of an atmospheric channel...

In this paper, using simulation in the software OptiSystem 7

The aim of this paper is to examine the impact of successive B frames using compression techniques (H.264 and H.265) and resolution (4K, 2K, Full HD and SD) when changing their quality in a television system. The analysis was done for a case when the number of successive B frames in the Group of Pictures (GOP) was B = 0 and B = 4. The results obtained for analysis parameters: compression ratio, Peak Signal Noise Ratio (PSNR), bitrate, P frames and B frames are presented by tables and graphics, based on which conclusions were made.