A few different light sources were tried before settling on lasers as the best option. These lasers are simple 3 volt red dot lasers that have been diffused with a piece of masking tape. The lasers were bright enough to be easily detected by the forward camera even in a brightly lit room.

Below is a screen shot showing what the forward camera is looking at (top half) and the reflection of the IR led on the eye (bottom half)

In order to recognize the beacons in software we apply some filters using Jevons Camera Veiwer software.