Abstract: An object sensing system comprises an array of emitters (3) and detectors (4). The emitters are arranged with overlapping fields of illumination such that each illuminates at least part of a space within which objects are to be sensed. Each detector is positioned to detect radiation reflected from the emitters towards it from any object in the space. The emitters are energized in a sequence such that the space is illuminated by each emitter in turn. The sequential energization of the emitters is correlated with an output of each detector to sense an object and its range within the space.