## 5 Experiments and Results
### System Evaluation and Discussion  
Figures 19-23 are examples of the head views. The visual inspection of the resulting cards (represented by two examples in Figures 24 and 25) clearly shows the three-dimensional visualization effect that was expected to be produced in the viewing of the cards.  
The Card3 DFace application offers a fast and affordable way to increase security in authentication cards and travel documents. It does not need highly sophisticated camera equipment for 3D image effect creation and does not use proprietary or sophisticated software packages, allowing for the easy implementation of this application. The results present themselves as reliable and adequate, providing a 3D effect of the face in lenticular cards through the laser printing techniques of the respective head views generated.  
It is worth noting that the angle difference in the generated head views is relatively low, although it is enough to create the 3D visualization effect. This angle difference is usually up to \(\pm 20\) degrees in relation to the frontal view of the face. Higher angle differences are not allowed due to two factors: on the one hand, the most important factor is the limitation of the viewing angle to keep the visibility of the card surface by a laser beam through the lenticular structure; on the other hand, the laser personalization machines themselves have physical limitations on the rotation angle of the card, which varies from machine to machine. Additionally, the 3D model of the head is also limited as it is reconstructed  
Figure 17: The correction of a mesh obtained using DepthSense camera [43]. We first standardized the scale and sampling frequency in relation to the database, and then we corrected using our filter. Figure (**a**) shows the acquired noisy mesh, (**b**) is only the texture, (**c**) is the filtered mesh and (**d**) is the filtered mesh with texture.  
Figure 18: The results obtained by our filter on different models. Column (**a**) illustrates the model with texture, column (**b**) shows the ground truth of the mesh obtained by a 3D scanner, (**c**) is the same mesh after noise, (**d**) shows the models filtered by our method without texture and (**e**) shows the textured filtered models.  
from a single frontal photo for practical reasons. Despite these limitations, the results demonstrated that a good 3D visualization effect is created in the printed cards, which validates the approach to this technology and its use to secure a person's authentication using ID and travel documents.  
Furthermore, due to the fast development and latest breakthroughs in the smartphone industry--devices which are very likely to generally have time-of-flight technology in their cameras (Huawei, Apple, Honor and others) in the future--reflecting on the possibility of using this application in a smartphone as well is relevant. In future work, we should also consider improvements in adapting some techniques related to the removal of radial distortion in images.  
Figure 19: Example head views generated for printing.  
Figure 20: Example head views generated for printing.  
Figure 21: Example head views generated for printing.