| 摘要 |
<p>PURPOSE:To exactly detect the number of person, even in case plural human bodies exist adjacently, by lowering a threshold value for detecting the next maximum point, when the maximum point of an output signal of an infrared-ray detecting element has been detected. CONSTITUTION:An output of an infrared-ray detecting element 2 which has been scanned by a scanning optical system 1 is amplified by a preamplifier 3, and brought to an A/D conversion, etc. in a signal processing part 4. Subsequently, in a maximum point counting part 51 of a deciding part 5, the number of the maximum points by which an inclination of an output signal from the signal processing part 4 exceeds a prescribed threshold value is counted as the number of persons. In that case, when the maximum point has been detected by the maximum point counting part 51, the threshold value is lowered by a threshold value changing part 52. In such a way, even in case plural human bodies exist adjacently, the number of persons can be detected exactly. Also, from an output signal of the maximum point counting part 51, person number information is outputted in an output part 6.</p> |
