| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an object detector capable of accurately controlling the opening/closing of a sheet shutter and the like by avoiding the problem that the sheet shutter and the like are left open though a passing object and the like do not actually exist, to the utmost, through the use of a simple constitution. <P>SOLUTION: This object detector comprises: a plurality of active optical sensors 1-4 which apply lights to a plurality of detection areas arranged on the basis of prescribed positional relationships, and which receive the respective reflected lights from within the detection areas; and a storage means 5 for storing the reference quantity of reflected light; and a control means 6 for outputting an object detection signal in a "detection-recognized state" in which a difference between the quantity of reflected light from within at least one detection area and the corresponding reference quantity of reflected light reaches a predetermined value or above in the at least one detection area, and for renewing the reference quantities of reflected light, associated with all the detection areas, when the "detection-recognized state" continues for a first predetermined period of time or longer only in less than a predetermined number of detection areas among the detection areas. <P>COPYRIGHT: (C)2008,JPO&INPIT |
