## 3 Methods of Determining of Image Number Lines
### The Analysis of Obtained Results  
The analyses were carried out on the basis of test images presented in Figure 7, which were the sources of undesirable emissions during their processed in the graphic tracks of IT devices. Signals corresponding to these emissions were recorded and used in the rasterization process, i.e., their reconstruction also in the form of images. The images presented in Figure 7 are only examples. The authors carried out several statistical tests for which other images were used (Figure 19). Obtained results for mentioned images only confirmed the conclusions stated below. During conducted tests, different scenarios were adopted. DVI, HDMI, and VGA graphic standards, printer displays, and display of terminal VoIP were tested (Table 5). These allowed us to check proposed methods and conventional methods from the viewpoint of suitability for determination of the number lines of reconstructed images. Results of detailed analyses are presented for images from Figure 7.  
For the process to be successful, however, the basic raster parameters are necessary, which are the length \(d\) of the image lines (image width) and the \(B\) number of image lines (image height). At the beginning, an assumption was made about the knowledge of the image line length \(d\) and the pre-estimated number \(B_{Entr}\) of the image line, which was carried out on the basis of the analysis of amplitude time variability of the revealing emission signal. The authors' experience shows that the accuracy of the rough calculation of the number of lines in the image is \(\pm 20\) lines. The rough estimation of the \(B_{Entr}\) parameter allowed for the estimation of \(B_{Corr}\) based on the methods of contrast evaluation (methods I, II, III, and IV) and the methods proposed by the authors of the article (methods V, VI, and VII). Taking into account the accuracy of the rough estimation of \(B_{Entr}\) quantity, the maximum value of the measure, calculated in the variability range \((B_{Entr}\pm n)\), where \(n=0,\ 1,\ 2,\dots,\ 20\), was adopted as the criterion for the correctness of determining the number of image lines. This means that the image height was decreased and increased in increments of \(1\), up to a maximum of \(20\) lines. As a result of the performed calculations of the values of the adopted measures (methods I to VII), the appropriate number of \(B_{Corr}\) lines for each reproduced image was determined (Table 6). Figure 18: Images reconstructed from the revealing emission signal measured at the frequency \(f_{o}=235\) MHz, for the number of lines of this image determined in accordance with the criterion of the maximum value of the measures presented in Figure 17: (**a**) the number of image lines determined in accordance with method V (\(B=273\), the number of lines smaller than required), (**b**) number of image lines determined in accordance with method I, II, III, IV, VI, and VII (\(B_{Corr}=288\), correct number of lines). Considering the effectiveness of the adopted methods, however, a discussion should be held on the dynamics of changes in the calculated values of the adopted measures in accordance with the relationships (2), (8), (11), (14), (22), (26), and (29).