## 4 Discussion
The characters 'a', 'c', 'n', 'o', 'u' and 'v' can be easily confused with each other (they have an almost identical shape in the restored image) and also the letters 'g' and 'y'. Next, we increased the font size to see if the quality of the restored image is improved and the results are not positive in this sense (the text is not intelligible), as can be seen in Figure 16.  
For intelligibility reasons, we have introduced blank spaces between alphanumeric characters written with secure asymmetrical and secure symmetrical fonts. The result can be seen in Figure 17. In this case, we consider that the letters 'b', 'c', 'd', 'f', 'p', 'q', 'r','s' and 't' can be identified for the secure asymmetrical font and the letters 'b', 'f','m', 'p', 'q', 'r','s' and 't' for the secure symmetrical font. The numbers from 1 to 7 can be identified for the secure symmetrical font, while the secure asymmetrical font makes it impossible to identify the numbers 5 and 6. Figure 13.0 Image recovered with Font 28: Arial, Times New Roman, secure asymmetrical and secure symmetrical. Figure 13.1 Image recovered with Font 28 with blank spaces: secure asymmetrical and secure symmetrical. Figure 13.2 Image recovered with Font 24: Arial, Times New Roman, secure asymmetrical and secure symmetrical. As we mentioned before, we can conclude that secure asymmetrical font is safer than secure symmetrical and for this reason we repeated the test in which all the alphanumeric characters were displayed with the fonts Arial, Times New Roman (TNR) and secure asymmetrical with dimension 28 (we skipped over dimension 24), as illustrated in Figure 13.3  
We can observe in Figure 18 that the fonts Arial and Times New Roman are 100% intelligible, while the secure asymmetrical font is not intelligible at all. We have further introduced blank spaces between alphanumeric characters to increase the degree of intelligibility, as illustrated in Figure 13.4  
Our attempt was partially successful, meaning that the letters 'C', 'E', 'F', 'G', 'L', 'P' and 'T' are 30% intelligible, as well as the numbers '5', '6' and '7'. Next, we wrote the alphanumeric characters with bold and the result can be seen in Figure 13.5 As we can see, the level of intelligibility for the secure asymmetrical font does not increase compared to Figure 13.6  
Since we were not successful in understanding the information written with secure asymmetrical font contained in the video restorations illustrated above, we increased the font to the maximum possible size from our point of view, respectively size 72. We have also left the font size 36 and 28 for comparison reasons and the result is shown in Figure 13.7  
In order to analyze the characteristics of each alphanumeric character of the secure asymmetrical font, we continued the tests only with the display of the size 72 characters and numbers, both for upper and lower case letters, as can be seen in Figure 22a-c.  
Figure 13.8 Font 28 with blank spaces: Arial, TNR and secure asymmetrical. Figure 13.9 Font 28: Arial, TNR and secure asymmetrical—upper case. From Figure 22, we can observe that certain alphanumeric characters have similar shape characteristics and can be very easily confused between each other if they are not even identical:  
1. lower case letters that have similar shape (Figure 22a) * the letters 'a', 'c' and 'o'; * the letters 'I', 'j' and 'r'; * the letters 'I' and 't'; * the letters 'g' and 'y'. 2. upper case letters that have similar shape (Figure 22b) * the letters 'A', 'B', 'D', 'O' and 'Q'; * the letters 'I' and 'J'. 3. the numerical characters can be differentiated between each other, as we can see in Figure 22c. Additionally, some numbers can be easily confused with the capital letters as follows: '2' with 'Z', '1' with 'I' and '8' with 'B'. Figure 11:0 Size 72, 36, 28 without blank spaces: secure asymmetrical font. Figure 11:1 Font 28 with blank spaces: Arial, TNR and secure asymmetrical—bold with blank spaces. Appropriate tests were carried out for VGA standard.