| 主权项 |
1. A person-detecting sensor for an automatic water faucet provided with an imaging unit that includes an imaging element in which pixels are arranged either one-dimensionally or two-dimensionally, and a light-emitting unit disposed offset from the imaging unit in a predetermined direction, wherein the imaging unit, receiving reflected light generated by light incident from the light-emitting unit, detects a person, as a detection object, located within a predetermined detection distance range, the person-detecting sensor comprising:
an imaging operation control unit that controls an imaging operation carrying out light emission by the light-emitting unit and light receiving by the imaging unit; a readout unit that reads out the respective received-light quantities of pixels constituting the imaging element; a range-finding unit that identifies position where the reflected light is incident in a light-receiving region, which is a region in which pixels constituting the imaging element are arrayed in the predetermined direction, and that decides whether distance to the detection object derivable by the principle of triangulation from the incident position falls within the predetermined detection distance range; a received-light quantity decision unit that performs a determination by a threshold with regard to the received-light quantity read out by the readout unit, and decides whether the received-light quantity is equal to or greater than a predetermined received-light quantity threshold; a detection determination unit that determines a detection object to be under detection state when distance to the detection object is decided by the range-finding unit to fall within the predetermined detection distance range and the received-light quantity is decided by the received-light quantity decision unit to be equal to or greater than the received-light quantity threshold; and a continuation decision unit that decides whether a state of a detection object being present is ongoing; wherein in the received-light quantity decision unit, after water discharge is started upon the detection determination unit determinating a detection object to be under detection state, for a period during which the continuation decision unit decides the state in which the detection object being present is ongoing, the received-light quantity threshold is set to be lower than prior to when the water discharge is started. |
