For good recognition, it is very important that the code is clearly visible and rich in contrast. The flashlight, which can be activated by the small flash icon, can make an extreme differenc. Even in good lighting conditions!
The adjacent images all depict the the same coin. The code was printed with white ink on a shiny surface, which is of course very difficult.
It is easy to see that the image appears totally different, depending on the light source, the tilt of the camera and the reflections on the surface. The topmost image is ideal for OCR recognition, while the other images sometimes can only be barely recognized or not at all.
Capslock AG | Gartenstrasse 35
8966 Oberwil-Lieli | Switzerland