*2.4. Defect Detection*

Solar modules are vulnerable to modifications in their surface; therefore, it is required to have a system to find faults. These kinds of faults and defects affect to the production of the module, making it not work at all in the worst cases. The problem is that the majority of faults are not detected with typical cameras (Figure 3), so it is necessary to apply different techniques such as thermography (Figure 3) or electroluminiscence (Figure 3).

The traditional way of finding faults is by performing a manual visual inspection, but the size of the solar farms has made this method almost unmanageable. In order to solve this problem, different techniques have been proposed, most of them using electroluminiscence.

**Figure 3.** Different techniques for photography modules. (**a**) Visual spectrum; (**b**) thermography; (**c**) electroluminiscence.
