| 摘要 |
PURPOSE:To measure the number of persons with high accuracy even if a detection area is wide, by measuring the number of persons by counting the maximum value of a signal obtained by scanning circularly the visual field of an infrared-ray detecting element. CONSTITUTION:A scanning optical system scans the visual field of an infrared ray detecting element. An output of the infrared-ray detecting element 2 is amplified 3, allowed to pass through a band-pass filter 41, and thereafter, A/D- converted 42, and outputted to a microcomputer 51 for constituting a judgement part 5. The microcomputer 51 inputs data of an input waveform accumulated in an input buffer, by one period portion of a circular scanning optical system 1. Subsequently, the microcomputer 51 reads out a reference waveform stored in advance from a memory, and subtracts it from the input waveform. As a result, a comparison processing waveform is generated. From this comparison processing waveform, the detection of the maximum point, and the counting of the detected maximum point are executed, and based on a result of counting of the maximum point, person number information is outputted. |
