JPH01140281A - Number of persons detector - Google Patents

Abstract

PURPOSE:To improve the accuracy for detecting the number of persons by alternately scanning an instantaneous visual field near to the center of a rotation and an instantaneous visual field remote from the center of a rotation at every half rotation by a circular scanning optical system for scanning the visual field of an infrared ray detecting element. CONSTITUTION:The circular scanning optical system 1 rotates elongated instantaneous visual fields Fa0, Fb0 by making the longitudinal direction a radial direction, thereby, circularly scans the visual field of the infrared ray detecting element 2. Then, the optical system 1 alternately scans the instantaneous visual field Fa0 near to the center of the rotation and the instantaneous visual field Fb0 remote from the center of the rotation at every half rotation. The light receiving output of the detecting element 2 is A/D converted by a signal processing part 4 and inputted to a decision part 5. A synchronizing signal part 16 generates a pulse P7 as soon as the visual field Fa0 enters the range of a detection and a pulse P2 as soon as it starts therefrom and generates a pulse P3 as soon as the visual field Fb0 enters the range of the detection and a pulse P4 as soon as it starts therefrom. The pulses P1-P4 are inputted to the decision part 5, a semi-circular visual field is divided radially into two to improve resolution and the number of person detecting accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an infrared receiving type people detection device that detects the number of people by detecting infrared rays emitted from a detected human body.

(Background Art) Conventionally, a number of people detection device as shown in FIG. 8 has been proposed (Japanese Patent Application No. 61-281301). This number of people detection device includes an infrared detection element 2, a circular scanning optical system 1 that circularly scans the field of view of the infrared detection element 2, a preamplifier 3 that amplifies the output signal of the infrared detection element 2, and a preamplifier 3 that amplifies the output signal of the infrared detection element 2. a signal processing section 4 that converts the output signal of the amplifier section 3 into a signal necessary for detecting the number of people; a determining section 5 that determines the number of people based on the output signal of the signal processing section 4; and an output signal of the determining section 5. and an output section 6 that outputs information on the number of people, and is capable of detecting the number of people within a wide detection area with high precision.

FIG. 9 is a diagram illustrating the configuration of the circular scanning optical system 1 used in the above-mentioned number of people detection device. This circular scanning optical system 1 has a concave cylindrical mirror 11 attached to a rotary plate 14 so that its generatrix direction is parallel to the radial direction.
0 rotation plate 1 configured by rotating by 3
The rotation axis 15 of No. 4 is arranged on the field of view center C of the light-receiving surface of the infrared detection element 2 . Infrared rays emitted from the background or the human body are reflected by a mirror 11 attached to a rotating plate 14 and guided to an infrared detection element 2.

The output of the infrared detection element 2 is amplified by a preamplifier 3 and then input to a signal processor 4. In the signal processing section 4, first, the input signal is input to a bandpass filter to cut unstable low frequency components and unnecessary high frequency components, thereby improving the S/N ratio. The output of the bandpass filter is A/D converted,
0 input to the judgment unit 5 In the judgment unit 5, the input waveform when there is no human body in the detection area is stored in advance as a reference waveform in the memory, and the input waveform is compared with the reference waveform in the memory. The presence or absence of human bodies and the number of people are determined at the same time. FIG. 10 is an explanatory diagram showing this situation, showing the input waveform (FIG. 10(b)) and the reference waveform (FIG. 10(b)).
a)), and the result is a new difference waveform (Figure 10 (C)). In the difference waveform, the voltage level is almost zero in the part where the human body is not present, and the voltage level is almost zero in the part where the human body is present. A convex waveform appears in the part. The determination unit 5 detects maximum points for this difference waveform, and calculates the number of maximum points as the number of people. In the differential waveform, if the number of detected persons is 0, the current input waveform is updated as a reference waveform and stored in the memory. In this way, by storing the reference waveform when a human body to be detected is present as background data in advance and performing comparison calculations with the input waveform, it is possible to detect the number of people without being affected by environmental changes within the detection area. It can be carried out.

However, since the optical system shown in FIG. 9 does not have resolution in the radial direction, as shown in FIG. 11(a), the human body M1. When M2 overlaps slightly, as shown in FIG. 12(a), the maximum point of the difference waveform becomes one, which may cause an error in detecting the number of people.

Furthermore, as shown in FIG. 11(b), since the distances from the detection device to the human bodies M + and M 2 are different, the energy of infrared rays incident on the detection device from the two human bodies M + and M 2 is large. In other cases, even though the human bodies do not overlap, as shown in FIG. 12 (1), there is only one maximum point, resulting in an error in detecting the number of people. In addition, FIG. 11(a).

In (b), arrow A indicates the scanning direction, and in both cases, short distance WX! The human body M1 on the side is the human body M on the far side
Scanned earlier than 2. Therefore, the small local maximum point due to the human body M2 is made inconspicuous by the large local maximum point due to the human body M.

In addition, as shown in Fig. 13(a), when the people detection bag Hs is used as a wall-mounted type, on the floor, the elongated instantaneous field of view F0 becomes visible as shown in Fig. 13(b). By rotating as shown by arrow A around the center C, a semicircular overall field of view F is obtained, but in this case, although it originally has an effective field of view of 360 degrees, only 180 degrees of it can be obtained. There was a problem that it could not be used.

(Object of the invention) The present invention has been made in view of the above points, and
The purpose of this is to make the instantaneous field of view of the circular scanning optical system switch between the short-range N side and the short-range I side every half cycle, so that a single infrared detection element can be used to switch between the short-range side of the semicircular field of view and the short-range side. An object of the present invention is to provide a number of people detection device that obtains human body information from a long distance and improves the accuracy of number of people detection.

(Disclosure of the Invention) In order to achieve the above object, the number of people detection device according to the present invention has an infrared detection element 2 and an elongated instantaneous field of view, as shown in FIGS. 1(a) and (b). Fao.

a circular scanning optical system 1 that circularly scans the field of view of the infrared detection element 2 by rotating Fbo with its longitudinal direction as the radial direction; a preamplifier 3 that amplifies the output signal of the infrared detection element 2; a signal processing unit 4 that converts the output signal of the preamplifier 3 into a signal necessary for detecting the number of people; a determining unit 5 that determines the number of people based on the output signal of the signal processing unit 4; and an output of the determining unit 5. In a number of people detection device comprising an output unit 6 that outputs number of people information from a signal, the circular scanning optical system 1 alternately scans an instantaneous field of view Fao close to the center of rotation and an instantaneous field of view Fbo far from the center of rotation every half rotation. It is characterized by having an optical system.

FIG. 2 shows a schematic configuration of a circular scanning optical system 1 used in an embodiment of the present invention. In this optical system, as shown in FIG. 2(a), two cylindrical mirrors 11
．． 12 is attached to the rotating plate 14, and each mirror 1
The generatrix direction of 1.12 is parallel to the radial direction. Moreover, these two mirrors 11 and 12 are shown in FIG. 2(b).
As shown in the figure, the respective generatrix lines are attached so as to form an angle of 180 degrees. The mirror 11 is attached at a position close to the rotation axis 15, and the mirror 12 is attached at a position far from the rotation axis 15. The rotating shaft 15 of the rotating plate 14 is arranged on the field of view center C of the light receiving surface of the infrared detecting element 2, and is rotationally driven by the motor 13.

The field of view on the floor obtained by this circular scanning optical system 1 is as shown in FIG.
a and the field of view Fb provided by the mirror 12. Also,
The instantaneous field of view due to each mirror 11.12 is Fao
, becomes Fbo. In the case of a wall-mounted type, the left half of the field of view is hidden, so the only part that is effective as a detection range is the right half, resulting in a 180-degree semicircular field of view. However, in reality, if a field mask is provided in the detection device to create a fan-shaped field of view of 180 degrees or less, as shown in Figure 3(,), mirrors 11 and 12 simultaneously absorb infrared rays from the human body. This is to prevent reflection.

The infrared rays reflected by the mirrors 11 and 12 are received by the infrared detection element 2 and converted into an electrical signal. The output of the infrared detection element 2 is amplified by a preamplifier 3 and then input to a signal processor 4. In the signal processing section 4, first, the input signal is input to a bandpass filter to cut unstable low frequency components and unnecessary high frequency components, thereby improving the S/N ratio. The output of the bandpass filter is A/D converted and input to the determining section 5.

The synchronization signal section 16 monitors the rotation of the circular scanning optical system 1, and generates a pulse at the moment when the instantaneous field of view of the mirror 11 or 12 enters the detection range and at the moment it leaves the detection range. The pulses generated by the synchronization signal section 16 are shown in FIG.

The pulse P1 is a pulse generated at the moment the instantaneous field of view Fao of the mirror 11 enters the detection range, and the pulse P2 is a pulse generated at the moment the instantaneous field of view Fao leaves the detection range. Moreover, the pulse P is the instantaneous field of view Fbo of the mirror 12
Pulse P4 is a pulse that is generated at the moment when Fbo enters the detection range, and pulse P4 is a pulse that is generated at the moment when instantaneous field of view Fbo leaves the detection range.

By inputting these pulses P and -P4 to the determining section 5, the determining section 5 can determine which field of view, far or near, the circular scanning optical system 1 is currently viewing.

In the determination unit 5, the input waveform when a human body is not present in the detection area is stored in advance as a reference waveform in the memory, and the input waveform is compared with the reference waveform in the memory.

In this embodiment, a comparison operation is performed between the input waveform and the 9-point waveform, and the result is used as a new difference waveform. Maximum points are detected for the differential waveform, and the number of maximum points is counted as the number of people. When the number of detected people is 0, the reference waveform is updated by the input waveform as in the conventional example. Output section 6
In this case, based on the number of people information given from the judgment section 5,
It displays the number of people and transmits it to a remote location if necessary.

In this embodiment, the functions of the first determining section 5 are realized by a microcomputer program. FIG. 7 is a flowchart showing the processing contents of the determining section 5. first,
When the pulse Pl from the synchronization signal section 16 is detected, the time of detection is set as the zero point on the time axis, and the variable representing time is set to 1.
=0. Then, the input value from the signal processing unit 4 to the determination unit 5 at that time is memorized in the array variable Ia(t).9 It is determined whether or not there is a pulse P2 from the synchronization signal unit 16,
If pulse P2 is not detected, a variable t representing time is counted up, and the input value at that point is stored in an array variable Ia.
Q). Hereafter, in the same manner, 1-〇, 1,
2. ... and the array variable Ia(0).

Store in Ia(1), Ia(2),... In this way, the input waveform Ia(t) in the field of view Pa on the short distance chick side can be captured.

When the pulse P2 from the synchronization signal unit 16 is detected, the value of the variable t at that time is memorized as the end time Ta,
A temporary stop signal P is sent to the motor 13. Next, an array variable Ra(t) indicating a reference waveform for the near field of view Fa is read from the memory. The array variable Ra(t) is
t" 0, 1, 2, -, Ta, the values of the reference waveform on the short distance side are stored in memory. For each time L=0.1.2..., Ta, Da(
t) = I a(t) - Ra(t) is calculated to obtain an array variable Da(t) indicating a differential waveform in the field of view Fa on the short distance side. Maximum points are counted for the differential waveform obtained in this way, and the detected number of maximum points is n and the detection times are stored as ta and -tan. If n=0, for each time t=0, 1, 2, -, Ta, assign the value of array variable I a(t) to array variable Ra(t) and update the reference waveform with the input waveform. Next, the motor 13 is started, and the pulse P from the synchronization signal section 16 is
Wait until it is detected.

When the pulse P3 is detected, the time of its detection is set as the zero point on the time axis, and the variable t representing time is set to 1=0. Then, the input value from the signal processing section 4 to the judgment section 5 at that time is stored in the array variable lb(L). Synchronization signal section】6
If the pulse P4 is not detected, a variable t representing time is counted up, and the input value at that point is stored in the array variable Ib(t). Similarly, t=o, t, 2. ... are input into array variables 1b(0), Ib(1), Ib(
2) Store in memory.

In this way, the input waveform r b (t) in the far field of view Fb can be captured.

When the pulse P from the synchronization signal unit 16 is detected, the value of the variable t at that time is memorized as the end time Tb,
A temporary stop signal P is sent to the motor 13. Next, an array variable Rb(t) indicating a reference waveform for the far field of view Fb is read from the memory. The array variable Rbm is L=
0.1, 2. ..., the value of the reference waveform on the far side in the case of Tb is stored in memory. Each time t=o,
1, 2. ..., for Tb, D b(L) = I
b(t) −Rb(t), and array variable D b(t
). For the difference waveform obtained in this way, local maximum points are counted, and the number of detected local maximum points is one, and the detection time is tb.
, ~tbm. -10, each time t=o, 1, 2. ..., for Tb, the array variable r
The value of b(t) is assigned to the array variable Rh(t), and the reference waveform is updated with the input waveform.

Next, the detection times ta, ~tan on the short distance side are compared with the detection times tb, ~tbm on the long distance side, and if there are matching detection times, the number k is counted. Then, add the number of people detected on the near side n and the number of people detected on the far side m, and subtract the number k whose detection times match on the near side and far side to find the number of people detected M. Next, the motor 13 is started, and the process waits until the pulse Pl from the synchronization signal section 16 is detected, and the same operation is repeated thereafter.

Next, the number of people detection operation will be explained using a specific example. In FIG. 3, when two human bodies Ma and Mb are standing, the difference waveform on the short distance side is shown in FIG. 5(a), and the difference waveform on the long distance side is shown in FIG. 5(b). Similarly, one human body Me
Figure 5 (c) shows the difference waveform on the short distance side when
Figure 5(d) shows the difference waveform on the far side.The difference waveforms in Figures 5(a) to (d) all have one peak, but the difference waveform in Figure 5(a) Comparing the difference waveform and the difference waveform of 5th [Z(b), the times at which the maximum points are taken are different, whereas the times at which the maximum points are taken are the same for the difference waveforms in Figures 5(c) and (d). be. Therefore, the number of local maximum points 1 in the difference waveform on the short distance side and the number m of local maximum points in the difference waveform on the long distance side are summed, and the maximum points of the difference waveforms on the short distance side and the long distance side are selected at the same time. By subtracting the number k of maximum points from , the accurate number of people detected M can be determined.

In addition, by dividing the field of view into two in the radial direction in this way, in the case shown in FIG. Even if it is applied to Fb, in the field of view Fb on the far side, the infrared energy from the human body M1 on the near side becomes relatively small, and in the difference waveform on the far side, there are two maxima due to the human body M1 and human body M2. You will get points together. The difference waveform on the short distance side at this time is shown in Figure 6 (a).
FIG. 6(b) shows the differential waveform on the long distance side. In this case, the difference waveform on the short distance side includes one maximum point Y1, and the number of detected people is n=1. In addition, the difference waveform on the long distance side includes two local maximum points Y2. Y, is divided, and the number of detected people is m=2. Among these, the maximum point Y1 and the maximum point Y2 occur at the same time tA, so the number of maximum points at the same time is 1. Therefore, the number of detected people can be determined as follows: M=n+m-=1+2-1=2.

(Effects of the Invention) As described above, the present invention provides an infrared receiving type people detection device that detects the number of people by circularly scanning the field of view of an infrared detection element and detecting infrared rays emitted from a detected human body.
Every half rotation, the instantaneous field of view close to the center of rotation and the instantaneous field of view far from the center of rotation are scanned alternately, so if you use a wall-mounted type, you can increase the resolution by dividing the semicircular field of view into two in the radial direction. This has the effect of improving the accuracy of detecting the number of people.

[Brief explanation of the drawing]

Figure 1 (a) is an explanatory diagram showing the field of view of the people detection device of the present invention, Figure (b) is a block diagram showing the basic configuration of the present invention, and Figure 2 (a) is a diagram of the circular scanning optical system used in the same. Front view, Figure (b) is a bottom view of the same as the above, Figure 3 (a) is a plan view showing the detection range of the above, Figure (b) is a side view of the same as the above, Figure 4 is the same as the above. 5 and 6 are waveform diagrams for explaining the operation of the present invention, and FIG. 7 is a flowchart for explaining the operation of the determining section used for the present invention. Fig. 8 is a block diagram of the conventional example, Fig. 9 is a front view of the circular scanning optical system used in the above, and Fig. 1
Figure 0 is a waveform diagram for explaining the operation of the same as above, Figure 11 (,)
, (b) is an explanatory diagram showing the visual field of the same as above, FIG. 12 (a),
(b) is a waveform diagram for explaining the operation of the same as above, and FIG.
) is a side view showing the detection range of the wall-mounted type of detection device;
FIG. 13(b) is a plan view showing the detection range same as above. 1 is a circular scanning optical system, 2 is an infrared detection element, 3 is a preamplification section, 4 is a signal processing section, 5 is a judgment section, 6 is an output section, Fa
o is the instantaneous visual field on the near side, and Fbo is the instantaneous visual field on the far side.

Claims (1)

[Claims] (1) An infrared detection element, a circular scanning optical system that circularly scans the field of view of the infrared detection element by rotating an elongated instantaneous field of view with its longitudinal direction as the radial direction, and a front panel that amplifies the output signal of the infrared detection element. a signal processing section that converts the output signal of the preamplification section into a signal necessary for detecting the number of people; a determination section that determines the number of people based on the output signal of the signal processing section; In the number of people detection device, the circular scanning optical system includes an optical system that alternately scans an instantaneous visual field close to the rotation center and an instantaneous visual field far from the rotation center every half rotation. A device for detecting the number of people.