| 摘要 |
<p>PURPOSE:To reduce the effect of noise and to enable detection of a human body moving at a low speed, by a method wherein threshold values prescribing the upper limits of a time difference between output times and being used for removing the noise and detecting the human body are changed over by outputs of infrared ray detecting elements delivered from a signal processing unit. CONSTITUTION:Two kinds of upper-limit threshold values T'MAX and TMAX of a time difference between output time are set beforehand in a decision unit 5. When a mutual time difference t of times tA to tD when outputs of infrared ray detecting elements A to D exceed a threshold value Vgamma does not satisfy a second determining condition TMIN < t < T'MAX ( where TMIN is the lower limit of the time difference t) on a human body, the respective output values FK(t) of all the elements A to D at the time when the time of the threshold value T'MAX passes from an output start time nt of an element (n) outputting first are checked up by an inequality ¦FK(tn +T'MAX¦ > Vgamma, and when no elements A to D satisfy this inequality, it is determined that the human body is absent. If any one of the elements A to D satisfies this inequality, the second determining condition is checked up again by using the threshold value TMAX. When this condition and further a first determining condition VMIN/VMAX > S (where VMIN and VMAX are the minimum and maximum values of peak values of the elements, and S a threshold value) are satisfied, it is determined that the human body is present.</p> |
