| 摘要 |
PURPOSE:To improve the number of persons counting accuracy by obtaining number of persons information based on an output signal at the time of rotating a circular scanning optical system in both normal and opposite directions in an infrared ray receiving type person number detector. CONSTITUTION:An infrared ray detecting element converts radiation heat information from a visual field scanned by the circular scanning optical system 1 to an electric signal, the output of the infrared ray detecting element 2 is fed to a deciding part 5 through a preamplifying part 3, a signal processing part 4 and the deciding part 5 decides the number of the persons based on a signal from the signal processing part 4. Herein, the output of a synchronizing signal part 7 is fed to the rotational direction signal part 52 of the deciding part 5, a direction reversing signal is fed to a control part 8 from the rotational direction signal part 52 and the scanning direction of the circular scanning optical system 1 is controlled. In such a way, a small output signal is prevented from being hidden by a large output signal produced immediately before by scanning in the normal and the opposite directions to detect the number of the persons in a detection area with the high accuracy. |
