[Source] An electro photo receptor (EPR) was the simplest kind of sensor. It integrated information from normal light, ultraviolet, and infrared telescopes to create a composite hologram or two-dimensional image. An EPR was useful only at comparatively short ranges, but was relatively inexpensive, and often saw use as a targeting sensor. Industrial Automaton's R2-series astromech droids were fitted with electro photo receptors.