JP3557949B2 - Human body detector - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a human body detector that determines human body detection from signals in two detection areas, and for example, to a human body detector used in a security alarm device or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a passive infrared human body detector has been used for a security alarm device that detects an intruder in a predetermined detection area and turns on and blinks an illumination lamp or warns with a buzzer or a siren. .
[0003]
This type of infrared human body detector constantly expands the detection area and constantly monitors the amount of infrared energy that changes in the area, and when a human body enters the area, the infrared light that enters the infrared detection element via the optical system Since the amount of energy changes to increase or decrease the amount of infrared energy radiated from the human body with respect to the amount of infrared energy radiated from the background in the area, the human body is detected from the change in the amount of infrared energy. I have.
[0004]
Furthermore, in the infrared type human body detector as described above, in order to prevent false reports and noise by small animals, and false reports on heat sources such as sunlight, a plurality of detection areas are configured, and each signal in the detection areas is A human body is determined by means such as AND of each signal (here also referred to as AND even if they are not all at the same time) so that the human body is determined if it occurs within a predetermined time difference. I have.
[0005]
[Problems to be solved by the invention]
However, in the conventional signal processing method in which two detection areas are formed and each signal is ANDed, the interval between the two detection areas differs from the initial setting depending on the height at which the sensor unit is mounted, and the detection area adjustment is performed. If possible, there is a problem that the setting differs from the initial setting depending on the angle of the detection area.
[0006]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a human body detector capable of easily resetting a time difference for detection determination to an optimum value. is there.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a pyroelectric element that converts incident infrared energy into an electric signal corresponding to the amount of fluctuation thereof, an amplifier circuit that amplifies the electric signal, and an infrared light condensing element that focuses infrared light on the pyroelectric element. An infrared type human body detector comprising an optical system for incidence, comprising a pyroelectric element unit, an amplifier circuit unit, and an optical system for configuring two detection areas for generating independent signals, and comprising a pyroelectric element and an optical system. The detection area determined by the positional relationship is arranged before and after with respect to the invasion direction of the human body, and is set so as to be separated by a predetermined interval without overlapping each other,
According to the first aspect of the present invention, the height at which the sensor unit is mounted is changed in a human body detector that performs detection determination when two detection signals in each independent area are generated within a predetermined time difference. In this case, there is provided means for simultaneously changing the time difference value for detection and determination in accordance with the area interval that changes when the angle of the detection area changes.
[0008]
According to the second aspect of the present invention, in the human body detector according to the first aspect, the value of the height at which the sensor unit is mounted and the angle between the two detection areas can be input by a switch or the like, and the optimum value is obtained based on those values. It has a calculation unit having a calculation function for resetting a time difference.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing an internal configuration of a human body detector according to the present invention. In FIG. 1, a human body detector includes a set of optical systems 11 and 12 for collecting infrared rays emitted from a human body, a set of pyroelectric elements 21 and 22 for detecting the collected infrared rays, and a pyroelectric element. A set of amplifiers 31 and 32 for amplifying the output of the above, a set of bandpass filters 41 and 42 for removing unnecessary frequency components and extracting only necessary signals, and an output from an amplifying circuit exceeding a preset threshold value Two signal outputs of the comparison circuits 51 and 52 for generating a pulse indicating the signal portion, the signal output circuits 61 and 62 for outputting the signals generated by the comparison circuit, and the signal output circuits 61 and 62 are generated with a predetermined time difference. In this case, the detection logic output circuit 70 that outputs the detection logic as being established, the mounting height input external switch SW1, the detection area angle input external SW2, etc., and the input mounting height value of the main body and two detections. A calculation unit 80 having a calculation function to reset the optimum time difference from the angle of the area, and a.
[0010]
As an example of the calculation in the calculation unit 80, a case where a detection area as shown in FIG. 2 is configured will be considered. Here, assuming that the moving speed of the human body G is v (m / s) and the detection area interval in the initial setting is L0 (m), a time difference T0 effective for human body detection is represented by the following equation (1).
Equation (1): T0 = L0 / v
Next, a case where the mounting height of the human body detector including the sensor unit is changed will be considered. When the height of the initial setting is H0 (m) shown in FIG. 2B and is changed to the height H1 (m) as shown in FIG. 3, the detection area interval L1 (m) becomes the following (2) Expression. Equation (2): L1 = L0 × H1 / H0
Until now, since the time difference T0 does not change, the time when the human body G actually passes through the detection area interval is different from the time L1 / v. In the case of H1 ≦ H0, the time when the human body G passes through the detection area interval is longer than the time. Since the signal is also detected and determined, the malfunction rate increases, and when H1 ≧ H0, the effective time is shorter than the time during which the human body passes through the detection area interval, so that the human body cannot be detected.
[0011]
Therefore, by resetting the time difference T1 to the time L1 / v during which the human body G actually passes through the detection area interval, that is, by setting T1 = L1 / v, the human body detection can be reliably performed without changing the signal processing method. become. Further, as in the above equation (2), L1 is determined by H1, so that it can be easily calculated.
[0012]
Also, consider a case where the angle between the two detection areas is changed. If the angles formed by the two detection areas with respect to the wall surface from the main body in the initial setting are θ1 (rad) and θ2 (rad) as shown in FIG. 2B, respectively, when L0 is the height H0, )
Equation (3) L0 = H0 × (tan θ1−tan θ2)
Next, as shown in FIG. 4, when the angles after the change are set to θ3 (rad) and θ4 (rad), respectively, the detection area interval L2 (m) becomes the following equation (4).
(4) Formula L2 = H0 × (tan θ3−tan θ4)
Here, by resetting the time difference T0 to L2 / v, that is, by setting T0 = L2 / v, the detection of the human body is ensured without changing the signal processing method. Note that L2 is two inputs of θ3 and θ4 when the two detection areas can be changed independently, and when the two detection areas change in conjunction, (θ3−θ4) is always constant and θ3 is constant. Alternatively, it is determined by inputting any one of θ4.
[0013]
Various definitions can be made for the detection area intervals described above, such as the intervals between the axes of the detection areas and the intervals between the ends of the detection areas, but these can be properly used according to the purpose. In addition to the input method using the DIP switch such as SW1 and SW2, for example, an ultrasonic sensor (not shown) may be provided by a structural mechanism to recognize the current height. Is automatically input to the calculation unit, so that the time difference can be automatically set.
[0014]
Further, in the detection logic output circuit 70 of FIG. 1, an output circuit for generating an output having a delay time when the detection logic output occurs a set number of times, that is, a timer that operates for a predetermined time when the detection logic output occurs once, By having a counter that counts the number of detection logic outputs that have occurred within a predetermined time of the timer from the occurrence of one detection logic output, it is also possible to set the number of occurrences of the detection logic output for detection determination according to the purpose It is possible.
[0015]
In addition, as described above, in the case of these embodiments, the two detection areas are considered with the configuration using the PIR sensor, but the present invention is not limited to this. Other sensors such as a combination of a PIR sensor and an IR sensor or a combination of a PIR sensor and an ultrasonic sensor are also possible.
[0016]
【The invention's effect】
As described above, according to the first and second aspects of the present invention, in the signal processing method in which two detection areas are configured and each signal is ANDed, the interval between the two detection areas is such that the sensor unit is attached. Depending on the height or the detection area adjustable, even if it changes from the initial setting due to the angle of the detection area, by resetting the time difference for detection judgment to the optimal value, There is an effect that the human body detection can be reliably performed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an internal configuration of a human body detector according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a detection area developed by the human body detector.
FIG. 3 is a diagram illustrating a detection area interval when the installation height of the human body detector is moved.
FIG. 4 is a diagram illustrating a detection area interval when an angle between detection areas of the human body detector is changed.
[Explanation of symbols]
11, 12 Optical system 21, 22 Pyroelectric element 31, 32 Amplifier 41, 42 Bandpass filter 51, 52 Comparison circuit 61, 62 Signal output circuit 70 Detection logic output circuit 80 Calculation unit H0 Initial installation height H1 Moving installation height L0 Initial detection area interval L1 Detected area interval L2 after moving the installation height L2 Detected area interval T0 where the angle formed by the detection area is changed Time difference T1 Optimal time difference v Human body moving speed

Claims (2)

Infrared human body detection comprising a pyroelectric element that converts incident infrared energy into an electric signal corresponding to the amount of fluctuation, an amplification circuit that amplifies the electric signal, and an optical system that collects infrared light and makes the pyroelectric element incident on the pyroelectric element In the vessel, two independent detection areas are arranged side by side with respect to the invasion direction of the human body, and are arranged so as to be separated from each other by a predetermined interval without overlapping each other. Is a human body detector that performs detection determination when the two detection signals are generated within a predetermined time difference, and includes a pyroelectric element when the height at which the human body detector is mounted is changed. Means for changing to a predetermined time difference value for a predetermined detection determination in accordance with the area height that changes when the mounting height of the part or the angle of the detection area is changed. The human body detector for the butterflies. Input means for inputting the value of the height at which the human body detector is mounted and the angle between the two detection areas is provided, and the optimum time difference for detecting and judging detection is calculated based on the value from the input means, and reset to the optimum time difference. The human body detector according to claim 1, further comprising an operation / setting unit having a function of performing the operation.

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