Any type of reflection (whether due to unwanted light or due to water/humidity) must be eliminated from the scene in order to avoid interference during the capture and/or beacon encoding.
Since the mouth is a highly humid environment, it is possible that the beacons are damp or wet before the capture is made. Therefore, it is very important to make sure before capturing:
- Minimize any light source, mainly with a high IR component, such as sunlight.
- Dry the beacons to remove any moisture they may have on the surface.