Optical realization and calibration of a light field generator
In this contribution, we introduce a novel light source allowing to generate multiple collimated light beams of which both the spatial location of the origin and the direction can be controlled. The realization of such a light field generator is based on a high-resolution display on top of which a micro lens array is mounted in the distance of its focal length. Consequently, the micro lenses emit collimated light beams if one of the underlying pixels is turned on. In order to be able to turn on a light ray originating from a certain macro pixel with a certain direction, a mapping from a two-dimensional spatial macro pixel coordinate and a two-dimensional angular coordinate to the two-dimensional coordinate of the respective pixel of the underlying display is needed. In our paper, we solve this calibration task with a suitable optical setup and appropriate processing methods. As an example application, we demonstrate how our prototype can successfully be used for the visual inspection of transparent objects by means of the inverse light field illumination method.