A spatial information detection system, which is capable of, even when detecting spatial information from a common target space by use of a plurality of detection devices, achieving accurate detection without causing interference between the detection devices. Each of the detection devices has a light emitting source for projecting light intensity-modulated with a modulation period into the target space, a photodetector for receiving light from the target space, and an evaluation portion for detecting the spatial information of the target space from a change between the light projected from the light emitting source and the light received by the photodetector. The system includes a timing control portion for controlling the timings of projecting the lights from the light emitting sources such that a light projection period of the light emitting source of one of the detection devices does not overlap with the light projection period of the light emitting source of another detection device.
Spatial information detection system including a plurality of detection devices with nonoverlapping light projection periods