## 1 Introduction  
Undoubtedly, the sense of sight is the most important human sense. It is estimated that 85% of the perception of information from the environment is made by visual observation. The perception of images, including their colors, by humans is a process that takes place in the brain [1,2]. Our eyes only detect electromagnetic radiation [3]. Additionally, the objects around us have no colors. They only reflect or absorb light waves of a certain frequency. Light is an electromagnetic wave, and an image, also colored, is a sensation evoked in the brain by nerve impulses generated in the retina of the eye.  
Taking into account properties of human vision, a solution for coloring images obtained in the process of electromagnetic infiltration has been proposed. Such images are reproduced using a palette of shades of gray [4,5]. The recorded compromising emanations contain information about the processed data in a graphical form. There is no information about the colors used on the primary side. Hence, in many cases, the obtained images are poorly readable, and the perception of the data contained in them is very difficult.  
It should be noted that the proposed image-coloring algorithm does not reproduce the actual colors of the data used by the user on the primary side. Coloring is primarily intended to improve their perception and thus increase the effectiveness of their analysis and perception of details that were not noticeable in the image in shades of gray [6,7].  
The existing methods of pseudo-coloring images are based on ready-to-use color-mapping tables (Look-Up-Table, LUT), which were created for other types of imaging. The images reproduced from the compromising emanation signals have a different specificity, they are usually noisy, disturbed, and their fragments corresponding to the information contained in the source images are distorted (they reflect only the vertical edges of the objects contained in them). Ready-made color maps are therefore of limited use in this case. It seems that the LUTs based on the use of exponential functions proposed in the article may be more useful, especially in the case of allowing the observer to change their parameters. The use of modified LUTs as a method of filtering the reproduced images is the subject of further work.  
An important problem related to the implementation of the proposed method is the strong variability of the conditions in which the generation and recording of compromising emanation signals takes place. They arise as one of many side-channel emissions related to the operation of various components of the tested device [8; 9; 10; 11; 12]. Even for different copies of the same type of equipment, they can differ significantly. Therefore, it can be difficult to prepare fixed color-mapping functions that are suitable for all cases. Therefore, it becomes necessary to allow the operator to change their parameters. This makes the final colorization results related to the operator's action, his experience, and subjective feelings. One possible solution to this problem could be the use of artificial neural networks. However, adapting them to different measurement scenarios requires a significant increase in their complexity.