Optimising Light Source Positions to Minimise Illumination Variation for 3D Vision

Machine vision lighting systems must be designed to evenly illuminate scenes, so that objects´ appearances do not change depending on their position. This is challenging when imaging 3D scenes where the camera´s field of view or depth of field are large. This paper describes a scheme to design effective lighting systems in such situations: lighting across the scene is modelled, and positions of lights are optimised to minimise variation in illumination levels. The scheme is used to design a lighting system for an agricultural robot, which reduces variation in the appearance of crops due to uneven lighting. The lighting for a compact medical imaging device is redesigned, which will result in a 53% reduction in the range of lighting levels in the scene.