| 摘要 |
<p>PURPOSE:To highly accurately detect a heat body even if a background temperature is changed by providing the title device with an infrared detecting means, a threshold level signal generating means and a comparing means. CONSTITUTION:The infrared detecting means 11 including a detecting element 1a generates an electric signal corresponding to infrared ray energy in a prescribed area. The threshold level signal generating means 12 forms a threshold level signal corresponding to the quantity of infrared ray energy radiated from the prescribed area. The comparing means 13 compares both level signals outputted from the means 11, 12 with each other and decides the existence of a heat body. Since the heat body is detected by comparing the signal outputted from the detecting means 11 with the threshold level signal, the influence of a changed in a background temperature due to the influence of sunbeams or the like or variation in a detecting signal level due to the fine movement of a static human's hand, foot, etc., in a monitoring area can be suppressed at its minimum.</p> |
