## 5 Conclusions
However, the use of the CZT transform requires the use of a hardware platform equipped with a significant amount of RAM, while the simulation results presented above indicate that even then the accuracy of the calculations may not be sufficient to obtain the raster parameter values that enable synchronous summation of signals corresponding to high-resolution images (Full HD and more). Therefore, the exact determination of the raster parameter values with the use of FFT and CZT transforms requires the use of additional mechanisms to refine these values using, for example, assessment measures of image quality. At a later stage of the work, it is planned to propose a measure of image quality assessment obtained on the basis of coherent summation and a criterion that will determine the acceptance of the image. Failure to meet the given criterion will force in further more accurate estimation of the image line length until the adopted criterion is met. For this, methods of the objective price of the images should be considered. The methods of objectively assessing the quality of visual content rely on the use of a computational algorithm, which, based on the analysis of visual content parameters, is able to approximate the average assessment that a given video sequence would obtain in the case of tests involving a group of testers. Due to the knowledge of the source information, the algorithms used in objective methods can be divided into three groups:  
* Algorithms using full knowledge of the source information;
* Algorithms using limited knowledge of the source information;
* Algorithms without access to knowledge about source information. The current methods of accepting of the determined values of the image line length and the number of lines in the image are based on visual assessment. Directly related to this is the ability to read graphic data contained in the reconstructed image. However, such a process is unacceptable due to the long time taken for the analysis of decision making. Automation of the process of determining basic rastering parameters is required. For this purpose, in a further stage of the research, measures and their acceptability criteria (image quality) will be proposed, which will allow for faster actions in the scope of determining the optimal line length and the number of lines in an image. Further work will focus on the analysis of the algorithm using full knowledge of the source information, i.e., sequences of high-quality visual content, and comparing this content with distorted content (the case that occurs in laboratory conditions during test device according to [41], which can process classified information). The measures that can be used to compare the reconstructed image with the reference image and which will be analyzed are:  
* Mean Absolute Error (MAE);
* Mean Square Error (MSE) or its Root Mean Square Error (RMSE);
* Peak Signal to Noise Ratio (PSNR). The described algorithm of line length estimation for the reconstructed images is extremely important for the effectiveness of the electromagnetic infiltration process and the assessment wireless communication devices from view point of their electromagnetic immunity. This is related to the quality of the recorded electromagnetic emission signals, which are strongly noisy signals. Conceptualization, A.P. ; methodology, A.P. and I.K. ; software, A.P. ; validation, I.K. ; formal analysis, A.P. and I.K. ; investigation, A.P. ; resources, I.K. ; data curation, A.P. ; writing--original draft preparation, A.P. and I.K. ; writing--review and editing, A.P. and I.K. ; visualization, A.P. and I.K. ; supervision, I.K. ; project administration, A.P. and I.K. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The authors declare no conflict of interest.