| 摘要 |
<p>PROBLEM TO BE SOLVED: To accurately monitor a monitoring area. SOLUTION: A distance sensor has a linearly extending detection area and generates output corresponding to the distance to an object existing in the detection area. A stepping motor 10 provided to the distance sensor 4 scans the monitoring area as a two-dimensional space within the detection area. This scan is performed dividing in a plurality of times. A CPU 18 controls the stepping motor 10 so that the detection area scans the scan direction between scan directions where the detection area scans in each scan, respectively in the scanning of other turn. A memory 22 stores the outputs of distance sensor 4 in non-detection state of the object at each scan direction as reference values. The CPU 18 compares the output of the distance sensor 4 in each scan direction and the corresponding reference value and the compared result is indicated on a display 26.</p> |
