| 摘要 |
<p>PURPOSE:To accurately update a waveform when there is no people as a reference waveform by deciding whether or not an input waveform and the wave in the last period are constant within a prescribed threshold value range, and updating the reference waveform when judging that they are constant continuously by a prescribed value indicating a preset period. CONSTITUTION:A waveform W1 which continues for a certain period (specific value T') in the past is the waveform in the absence of a human body and stored in a 2nd waveform storage part 52 while being considered to be updated as the reference wave with high possibility. Thus, when a human body enters a detection area temporarily and exits from the detection area immediately, the value C1 of a 1st counter 53 is not recounted from 0, but counted from the value right before the human body appears. Consequently, even if a human body enters the area and exits frequently, the reference waveform R can be updated.</p> |
