The O2D9 series ring lights provide uniform light to the field of
view in infrared, visible red and white light versions. Unlike many
external lights for vision sensors, these units can be triggered or
permanently on, and can be operated at high intensity for a stronger
light.

As the light is more homogenous, it helps avoid shadows on the
subject and also prevents hotspots, which can occur on curved surfaces
in particular. Stand 201