JPS5983078A - Apparatus for detecting crowdedness degree - Google Patents

Abstract

PURPOSE:To make it possible to measure the number of persons with good accuracy while obtaining signals corresponding to the number of persons in a visual field, by a method wherein an output signal is held as a sample value and output is generated when the difference of said output signal and the sample value exceeds a predetermined value. CONSTITUTION:When the analogue switch 84 connected to a condenser 82 is short circuited to the earth, a current is flowed to the condenser 82 and the instantaneous value of an analogue signal to zero volt is sampled. When the analogue switch 84 is opened, the sample value at that point of time is charged to the condenser 82 and the potential Vg at a G-point is imparted as the difference of potential Vi of 21c and the sample value. A comparator 86 compares the potential Vg at the G-point and the potential Vr at a R-point to outputs potential of 21c. That is, a formula Vg=1 (Vg=Vr) is formed. Herein, Vr is a threshold value imparted by a volume 87. By this method, the signals corresponding to the number of persons in a visual field is obtained and the number of persons can be measured with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that measures the number of people from infrared radiation emitted by a human body. The invention relates to a signal processing circuit that separates and detects signals based on infrared radiation from the floor and the background.

For example, it is very effective when it is required to know the number of people in a given place such as an underground mall, a station, a road intersection, an elevator ball or an escalator entrance, and to know the degree of congestion depending on the situation. As such, the applicant has previously proposed a congestion degree detection device. This congestion level detection device is
There is a method of measuring the number of people by scanning at a fixed period with a scanning mirror and using the relationship that the width of the output signal waveform of a detection element that responds to changes in incident infrared rays is proportional to the number of people being measured. explain.

Figure 1 is a diagram for explaining the above scanning method, and (a)
(b) shows the object plane scanning method, and (b) shows the image plane scanning method. In FIG. 1, 1 is a scanning mirror, 2 is a condensing lens, 3 is a detection element, 4 is an imaging plane, and 5 is infrared rays emitted from a measurement target. Object plane scanning in (a) is a method in which a detection element is placed on or very close to the optical axis, and scanning is performed by changing the direction of the optical axis by rotating or swinging a mirror. In this scanning method, the detection element is placed on the optical axis or very close to the optical axis, so the angle of view of the optical system can be small, and good optical performance can only be achieved close to the optical axis. good.

However, the scanning mirror needs to have a large diameter, and rotating or swinging it involves various difficulties. -・way,
The image plane scanning method (b) is a method in which scanning is performed without changing the direction of the optical axis and by moving the detection element arranged on the image plane. In this case, the detection element is actually fixed, and the focused energy is imaged on the detection element by rotating and swinging the mirror, which is placed after the condensing system. In this method, it is necessary that the entire scanning width of 1.1 points is focused on the image plane, so an optical system with a wide angle of view is required, and good optical performance can be achieved even in areas far from the optical axis. However, since the scanning mirror can be placed close to the image plane, it can be small and the scanning mechanism can be simplified. In principle, the scanning method of the present congestion level detector may be the h method, but an example in which the image plane scanning method is adopted in order to simplify and downsize the mechanism will be described below.

m21A c shows an example in which the congestion degree detection device 10 is installed at an angle of depression on the ceiling of an elevator hall and detects infrared rays 14 emitted from waiting customers 13. 12
is an elevator car. 31'4 shows the optical system of the mixing degree detection device [tL]. 11 is an optical system housing case, 15
is a rotating plane mirror (nephroscope), and its 1J4 structure emits infrared radiation on the surface of synthetic Tfil fat (very good glass).
It is made by vapor-depositing aluminum or chromium with 1 flaw at a rate of A=1, /IS, Tl ('J motor 16 rotates with rotation +lb 16a. 17 is a synchronous pulse detection section and a photointerrupter rotates with the same rotation! II
This signal is generated and sent to a synchronization circuit, which will be described later.

13a to 13e are infrared detection elements, in which a plurality of inexpensive pyroelectric detection elements having high quality and stable characteristics are arranged. For these elements, a window material (not shown) with a cut-on filter that blocks light with a wavelength of 671 m or less is used to eliminate the influence of sunlight and bright light. 19 is an infrared lens. It is required to have high transmittance for infrared rays emitted from the human body in the wavelength range of 45 to 20 pm.Germanium lenses and silicon lenses are suitable for this purpose.The purpose of using this lens is to transmit infrared rays. In order to ensure the operation of the detector, the lens focuses infrared rays and increases the energy density of the element's light-receiving surface, increasing the output signal, but when the target is relatively close (within a few meters) ), depending on the application, it is not necessary to use a lens (the radiation energy density decreases in inverse proportion to the square of the distance).The important points of the optical system as shown in Fig. 3 are as follows.

(]) The two-dimensional field of view is covered by the rotation of the scanning mirror 15 in the X direction.
multiple infrared detection elements 18 arranged in the X direction.
Depends on a~θ. Note that the number of detection elements is not limited to five, and may be selected depending on the resolution of the field of view in the X direction and the degree of accuracy required.

(2) Image plane scanning is performed by the scanning mirror 15, and in order to maximize the field of view in the X direction, the lens 19 and the detection elements 18a to θ are installed closest to the rotating outer edge of the scanning mirror 15; Even so, the visibility in the X direction (determined by the position of the sensing element in the y/j direction, the theoretical limit angle can be close to 180°)
Compared to this, the viewing angle in the Xb direction is relatively narrow determined by the F value (focal length/'aperture) of the lens.

(3) Due to the image plane scanning method using the scanning mirror 15, the lens 1
As the scanning angle (left, right) increases from the center of 9's C axis, the red light from the target increases! Ij'l 'A・I or the optical path of the path reaching the sensing elements 18a-e (lens 1
In addition to reducing the effective surface of ff1 and the force iρ of 9, the detection element +8
Person q・t rfI increases from a to e) 11・k
The contribution of the radiation inside the sensor is increasing. The inner temperature of the yC academic accommodation case 11 has a taste.

(4) Depending on the setting of the optical gain including the infrared transmittance of the lens 19, the equivalent temperature of the amount of infrared radiation incident on the sensing elements +8a to θ generally differs from the actual temperature (
The equivalent temperature is based on the internal radiation amount based on the sensor inner wall temperature).

(5) Pyroelectric elements are used as the detection elements 18a to 18e, and a feature of their operation and function is that they do not respond to constant incident infrared rays. Therefore, although information on the ambient temperature of the sensing elements 18a to .theta. is lost, information on the difference from other radiation due to scanning, that is, information on the alternating current component, remains. Therefore, the electric signal waveforms from the detection elements 18a to 18e reflect the amount of radiation fluctuation based on the inner wall temperature of the sensor, and the absolute values of all voltage levels have no meaning, only the potential difference between them. has meaning.

The waveform of the amount of infrared radiation incident on the detection elements 113a to 113e obtained as the scanning mirror 15 rotates will be explained based on the scanning characteristics of the optical system described above. For convenience, only the field of view in which the sensing element 113c can detect ijJ will be considered here (
The other four sensing elements also differ in the field of view to be detected, but the functions described below are exactly the same.)

FIG. 4(a) shows an example where there are three targets, one near the edge of the visual field and one at the center of the visual field.

The dash-dotted line represents the internal radiation of the sensor, which decreases from the field edge toward the center of the field, rises again, and becomes an internal-only radiation level again at the opposite field edge. On the other hand, for the target, as shown by the solid line, it is maximum at the center of the visual field and small near the edges of the visual field. The dashed line represents the optical gain curve. The vertical axis shows the radiation amount as an absolute amount. The sum of radiation from the target and radiation inside the sensor enters the sensing element 18c.

In reality, the radiation from the indoor floor attracts people, but for the sake of simplicity, we will ignore it here. The total radiation amount distribution is shown in Fig. 4(b).

As can be seen from the figure, because of the optical gain curve, the radiation from the target is quite small near the field of view edge (= J), but on the contrary, the internal radiation is large, so the two are added together and the peak value of the radiation amount distribution within the field of view However, as mentioned above, the absolute level in Fig. 4(b) is not preserved (for example, the internal radiation level varies upward depending on the waveform), and only the radiation fluctuation is important. Become.

That is, the output voltage θ of the sensing element 18C is the incident radiation jI'(
,' Since the output is proportional to the change in W, if you take the change based on the waveform in Figure 4(b), the peak value will be almost constant, and if an appropriate threshold value is given, it will be within the field of view. Relatively uniform pulsing results in [iJ performance. As for the signal waveform, due to the resolution of the optical system and the response characteristics of the detection element, the target waveform is quite blurred, and the cedar shape is approximately triangular waveform. However, the falling time constant is particularly long, so it is a bit of an integral wave.
It has been transformed into a shape. Therefore, compared to the peak value of an isolated waveform with one LI target, the peak value of a waveform with two people standing close to each other is approximately twice as large. Since the general shape is triangular, the width (it) will also be approximately twice as large (if the sensing element is of a high-speed response, small resolution type, the peak value will remain the same and the width will be doubled).Experiment According to the three great blessings-
It was found that in the case of 1-, the peak value is about twice that of the case of one person, and only the width is multiplied by the number of people (in the case of three people, it is six times, and 4
4 times for humans). In other words, only the width shows a proportional relationship with the number of people. The congestion level detection device utilizes this relationship, and has become capable of detecting the number of people regardless of the density of the people or their location (as the peak of the signal is not used). From the results of experiments, it has been found that a large number of people can be detected with high accuracy by IY, which determines the number of people from the width of each waveform using the width of the waveform for two targets (in a continuous state) as a reference.

Next, a fifth example of the configuration of the circuit 111η of the congestion level detection device is shown. In addition, the same thing as in Figure 3 61 times - l? It is shown in No. 9. In FIG. 5, 18a' to 18o' are the output signals C1) of the sensing elements fA8a to 18θ in FIG.
20a to 20e in ii constitute five systems, which are manually powered by the band filter circuit group 21. Here 7・fru's fi
The t-range cutoff frequency can be determined by considering the scanning circle 1jJl of the scanning mirror as -, and is preferably about 0111z (the higher the chopping frequency, the lower the response sensitivity of the imbalance detection element). Also, the high cutoff frequency is approximately 40117mm to remove noise components caused by the commercial power frequency. Just set it to . Outputs 21a~ from 5 systems of bandpass filters 21
21θ is input to the main amplifier circuit group (5 systems) 22.

The configuration of the main amplifier circuit group 22 is as shown in FIG. 6, and there are five systems, but since it is simple 4i, only the bandpass filter output 21c will be considered for one system (signal from FIG. 3 18c). 31 is an amplifier, 31c is its output, and 32 is a comparator, which outputs a pulse signal 52c with a signal higher than a predetermined threshold level. 63 is an A N D circuit that can be detected only during the time of the wind pulse 26a (details will be described later) and outputs an output 22c. FIG. 7 shows the waveforms and timing of each part of the sixth part. FIG. 7(a) shows the waveform of 31c, and if there is a person within the detection field of view, the waveform will be as shown by the broken line in the same figure. (b) The figure shows a 32G signal waveform, and the threshold level T is determined by the comparator 62.
Only signals of 11 or more are taken out and become pulses of positive logic level. Figure (C) shows the waveform and timing of the wind pulse 26a, which is generated by the same Iυ1 circuit 26 in Figure 5 (details will be described later), where 0'■' is the opening timing and CT is the closing timing. and these are variable, being the time between OT and CT or the time width of the oral channel. This wind pulse 26a
By providing this, the field of view of the detector can be adjusted. In addition, A! '; You can also avoid the action.

The example shown in FIG. 7 is a waveform when there are four people in the field of view, and one person is being poked by b', two people (there are people in a row - C), and b''b''''.

Returning to FIG. 5, 23 is a tintal multiplexer circuit which outputs five systems of pulse power as one system of pulse trains. This tintal multiplexer circuit 23
In order to measure the width of the pulses as shown in FIG. 7(b) taken out by the outputs 22a to 22e of the main amplifier circuit group 22, as an example, it is output as a sequence of the number of clock pulses corresponding to the width of each pulse. 23a is taken out. t of the tintal multiplexer circuit 23 in FIG.
, l, 7 configurations are shown. In FIG. 8, a clock pulse 31a is generated by a 311t; lt astable multi-by-break, which is further divided by a decimal ring counter 32,
Five systems of clock pulse groups 32a shifted by 115 cycles
-32e is generated. 33 to 37 are NAND gate circuits, 43 to 47 are gate circuits, 50 is an inverter, and P is a positive power supply. Therefore, when a pulse is input to 22a to 22θ, a sequence of the number of clock pulses corresponding to the width of the pulse can be taken out as the output 23a.

Returning to FIG. 5, 26 is a synchronous circuit, and the main amplifier circuit 2
2, and outputs 26a and 26b which provide the operation timing of the argument circuit 24, respectively.

Controlled by 26c. Synchronous circuit 26
The configuration is shown in FIG. 9, and the timing chart is shown in FIG. 10. In FIGS. 9 and 10, 17a is a synchronization signal (timing pulse) taken out by the photointerrupter 17 shown in FIG. Shown in Figure (a).

Reference numeral 26b is a reset pulse obtained by the timing pulse j7a via the delay circuit 65, which is used to reset the counter contents of the 3t number circuit 24, and its waveform is shown in FIG. 10(b).

Reference numeral 61a is a start pulse obtained through the intermediate stable multivibrator 61, whose waveform is shown in FIG. 10(C), or the time width T can be set arbitrarily. 62
a is a pulse for determining the publishing timing of the wind pulse 26a, and 66a is a pulse for determining the publishing timing of the wind pulse 26a.
These are the pulses for determining the closing timing of the start pulses 61a and 2.63, which are obtained from the start pulses 61a and 2.63, respectively, and are shown in Fig. 10(d).
) and (e) show the waveforms. 64 is NOT circuit and A
It consists of an ND circuit, and by manually inputting the pulse 7S2a to the NOT circuit and combining this output and the pulse 63a with an AND circuit, a wind pulse 26a can be obtained as shown in FIG. 10(f). As mentioned above, by setting the wind pulse 26a, the detection field of view can be limited, and since the humidity inside the optical system housing case (back side) is not detected, there is a small way to avoid malfunctions caused by this.
is the same as the timing pulse 17a, and the counting circuit 2
Four messages are sent, and the contents of each column are searched until the next message is sent. FIG. 10(g) shows the waveform of the output 22C of the main amplifier circuit 1; 122 when there are four people within the detection field of the detection element 13c as explained in FIG. It is. Figure 10 (h) (Well, the waveform of the clock pulse 31a in Figure 8 is shown in Figure 10 0) to (m)
are clock pulse trains frequency-divided by the decimal ring counter 32, and have waveforms 32a to 32111, respectively.

Therefore, Figure 10(n) is 220 in (g) and 32 in (k).
It represents the waveform of FIG. 8 23a synthesized from signals c, and corresponds to a pulse width of 220, that is, the number of people in the field of view. ＜You can obtain the Rus sequence.

Returning to FIG. 5, 24 is a word count circuit composed of a counter. In this circuit, a signal 23a is used to count the number of pulses manually, or to an IIT that rotates a scanning mirror once, and outputs a signal 24a representing the number of people within the field of view. 25 is an output device.

Output device (such as a number of people display or a control signal device that outputs according to the degree of congestion).As a number of people display,
For example, a 7-segment LED may be driven by a Tecoder (omitted). Also, the control signal output in response to the degree of interference can be obtained, for example, by using a flip-flop circuit (omitted).

In the above embodiment, the field of view of each detection element in the X direction in FIG. 3 differs depending on the characteristics of the lens system (18
a, 18θ or minimum, 18c or maximum). Therefore, the wind pulse can be varied for each channel, and unnecessary areas can be cut, making it possible to clearly see the field of view for each channel and avoiding the effects of temperature fluctuations on the inside of the case. sensing element). Furthermore, by making the wind pulse variable, the detection field of view can be set arbitrarily, increasing the degree of freedom in the installation environment.

Further, if the threshold level of the comparator shown in @6 Fig. 62 can be automatically adjusted according to the ambient temperature, sensitivity unevenness due to seasonal temperature fluctuations can be suppressed.

To achieve this, a temperature sensor is built into the optical system housing case (as a thermistor or a temperature sensor controller).
), the threshold level should be set by using the fluctuation of the output voltage due to temperature (circuit omitted)
.

In addition, in the embodiment described in -1-, the coating on the back surface of the scanning mirror was applied only to one side of the flat plate, but the coating may be applied to both sides of the flat plate. In this case, the synchronization signal extracted by the photointerrupter The scanning mirror is −
・It is sufficient to generate two pulses in the rotating ITf. In this case, the rotational speed of the motor may be reduced to 1/2, which is effective in reducing rotational noise. Further, the shape of the scanning mirror is not limited to a flat surface, but may be a polygonal column (polygon mirror) or a curved surface.

FIG. 11 shows another embodiment of the scanning mirror. In this example, the scanning mirror 70 has a flat coating surface 7 on a rotating shaft 71.
0a, and a coating surface 70b that is oblique to the rotation 1111I171. With this configuration, when the output from the detection element obtained by parallel scanning of the coating surface 70a (parallel to the Oblique to 41+)? By combining the output signals from the sensing elements, it is possible to increase the ability to reach 1 m outside the layer, and eliminate the presence of insufficient field of view (dead zone) due to the gap between the sensing elements. .

The above is the content of the congestion degree detection device 61 proposed earlier.

By the way, as the detection element of the above-mentioned congestion 1 degree detection device, an inexpensive and high quality Xiao 1L type is used.

As mentioned above, this is a differential type in principle and can provide an output proportional to the fourth power of the humidity difference between the background temperature and the object to be measured, but it does not respond to steady incident infrared rays. That is, by scanning, only information on the difference from other radiation (information as an alternating current component) is output. In addition, due to the influence of ambient temperature, etc., the internal radiation level of the detection unit fluctuates up and down, and the detection element output signal waveform also changes. Setting a fixed threshold value may cause false alarms. Furthermore, depending on the threshold acid ffl, it is necessary to narrow the width of the wind pulse and therefore the detection field of view.

The present invention has been made in view of these points, and its purpose is to detect signals based on infrared radiation from human targets without being affected by ambient temperature or narrowing the detection field of view. It is an object of the present invention to provide a device that can separate signals based on internal radiation and therefore can accurately determine the number of people 1i (II).

A feature of the present invention is that a sample value is held at a rotation angle corresponding to the internal radiation amount to provide a reference potential for comparison, and the sample value is held using a zero-volt clamper and a diode clamper. , 1 non-plink at a fixed timing and zumbling at a timing corresponding to the point of change in the sign of the signal. Furthermore, by performing zero-volt clamping, it is possible to simultaneously perform gate action.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 12 is a diagram showing the circuit configuration of the congestion degree detection device according to the present invention, which corresponds to the main increaser circuit IF in FIG. Although only one of the systems (corresponding to Fig. 6) is shown, the same applies to the other systems. Note that the parts omitted from illustration are the same as those in No. 51J, and the same parts as in FIG. 5 are designated by the same reference numerals.

In Fig. 12, reference numeral 81 is a harmonium amplifier for inputting analog signals at low impedance (J''In).
2 is a content for clan pink. 87 is a volume for setting a threshold voltage, and 83 and 84 are analog switches. When the analog switch 84 following the capacitor 82 is short-circuited to ground A↓, current flows through the capacitor 82 and the instantaneous value of the analog signal with respect to the zero halt is sampled. When the analog switch is opened, the sample value at that point is charged to the capacitor 82 at λt, and G
The potential Vg at the point is rj, which is obtained as the difference between the potential Vi of 21c and the linear pulley 1 (1, that is, Vgtt) - (contact 01tl of the switch 84) V
g(t) = Vi(t)-Vi(ts) (switch 8
4 contact is OFF) (fμ, t represents time, ts is when switch 84 is OFF)
Indicates the time at the moment it becomes FF. ) Furthermore, depending on the path of the analog switch 83, 0N-OFF is different from the unconditional sampling described above, and polar sampling (condition (=J key ring)) by the diode 85 is added. That is, in the ON state, Vg (shi) = o (Vg (7)
O) Vg(t) = Vj,(t) −Vi(t
s) (Vg(t) > 0) However, ts is the time at the moment when Vg(shi) changes from negative to positive.

A comparator 86 compares the potential Vg at point G and the potential Vr at point R, and outputs vo of 22c. That is, Vo-+ (Vg≧Vr) Vo = D (Vg<Vr) Here, -CVr is the threshold value determined by J. Ryuno, 87.

P' is the power supply voltage at the end, 62' (corresponding to the 9th [hyphen 62]) f
Pulse 62a' (Fig. 9, 62
Equivalent to a, opening timing pulse is abbreviated as O
63' (corresponding to 63 in Figure 9) is an analog switch 8.
Pulse 63a' that defines the interval 1111 from opening 4 (unconditionally -+ at J) and then closing the gate.
(corresponding to 63a in FIG. 9, hereinafter referred to as a closing timing pulse for short as CTP) is a monostable multivibrator which is the same as that shown in FIG. 9.

The die AD 85 is for performing polarity summing, the analog switch 83 is of a normally open type, and the analog switch 84 for performing unconditional summing is of a normally closed type.

61a is a start pulse that determines the timing of OTP and CTP, and is the same as that shown in FIG.

Next, before explaining the operation of this circuit, the characteristics of the waveform to be processed and the necessary items to be processed will be summarized below. 1st
FIG. 3 shows an example of the signal 2IC to be processed.

(++ When the target does not exist within the field of view (see the solid line waveform in Fig. 131), the periods B-0 and C-D for looking at the floor, which is the target field of view, are different from the detection unit internal scanning periods A to B. Generally, it is in the negative direction.The first reason is that the temperature of the detection part is higher than the temperature around the gradient due to the self-heating of the detection part (heating of the motor, heat generation of the preamplifier).The second reason is that the temperature of the detection part is higher than the temperature around the gradient. Because it is located higher than the floor, the ambient temperature of the detection part is higher than the floor due to the temperature difference between high and low due to the normal temperature distribution in the room (the ceiling is high and the floor is low).For this reason, A-B The potential difference between B and D changes every moment.Here,
Even if there are changes in the floor temperature or the temperature of the detection part, it is essential that false alarms are not issued and that the target is not missed.

The human body 1" mark is always higher than the floor temperature 19, so IJJi
Do I have to choose a high threshold value?
The target humidity value is not necessarily higher than the detection unit σ for each month. Intermediate or detection part. It is a must to set the temperature ≦ threshold value. At that time, in order not to issue false alarms near both ends of the field of view, the gate function (11J et al.) is necessary.As this gate function, the timing OT to open the gate and the timing C and T to close the gate are set.
OTP from star I/pulse generation timing, respectively.
It is necessary to generate an OTP and electrically limit the field of view, and it is necessary to hold the OT's V 1 (t) to 1 non-pull value.

(Many) When there is a goal of one major favor (see the broken line waveform in Figure 13).

The figure shows an example where an isolated single target exists at the center of the visual field. It is sufficient to add a threshold value Vr to the sample value in OT and to pulse the portion exceeding the threshold value (hunted portion). Here, if the OT is fixed, the pulse will not be emitted if the target is at the OT position, and in that case, even if there are rlrJ other targets or the target is full, the Yampuru value at the OT is the equivalent humidity from the 1" mark
= 1, so it has the serious drawback that no pulse can be obtained.

That is, in the case of OT fixation, that position becomes a singular point, which is affected by the existence of a human being there, which essentially causes a reduction in the viewing angle. Therefore, to prevent this, OT
During the period P, if there is a target, the differential coefficient of the signal waveform will always be positive, so if the positive inversion position is set as the actual OT, the above-mentioned drawbacks will be eliminated. The present invention realizes a combination system of Precera l-OT and automatic OT (automatic adjustment of OT) with a simple combination of elements (details will be described below).

Next, the operating principle of this circuit will be explained in terms of operation mode and distribution of marks.

FIG. 14 shows the relationship between operation modes and timing pulses. (a) is the start pulse 61a, which corresponds to when T=0 in FIG. 10(c), and is the timing pulse in FIG. 10(a).

': Pj14 Figures (b) and (c) are the opening timing pulse (OTP) and closing timing pulse (CTP), respectively, which are based on the synchronization that occurs at the special 5P position with the scanning mirror rotation angle. Published on. 62' and 63' in FIG. 12 are used to perform this function. The timing when the OTP changes from 1 to 0 is defined as the closing timing (OT), and the timing when the CTP changes from 1 to 0 is defined as the closing timing (CT). O
TP is OT analog switch 83 in Figure 12. P is 8
Used to control 4ヲFfilJ. The analog switch 83 circuit is connected to ground through a diode 85, and the analog switch 84 circuit is unconditionally connected to ground. Therefore, the parallel circuit of analog switches 83 and 84 is o'rp-i It7J ItU, f
From JIJ start pulse generation timing (ST) to O
During the period up to T, if Vg < O, it is a short circuit, and Vg ≧
If it is 0, it is an open condition.

Next, during the period from OT to OT, it operates in an unconditionally open mode (mode I+) without short circuits.

Finally, during the period from OT to ST, it operates in a mode (mode m) in which there is no release and an extremely short connection.

Therefore, according to the present invention, when a target exists between ST and OT, a sample value at a timing one center relative to the point of change in the sign of the signal is given as a comparison reference potential, and a target between OT and OT is provided as a comparison reference potential. Since the sample value at a fixed timing is given as the reference potential for comparison, it not only prevents the influence of ambient temperature etc.
The detection field of view can be widened regardless of the setting position.

Next, the operation will be explained based on specific signal waveforms.

■For the waveform shown in Figure 13 a) Mode m of the previous cycle, ! 7- At the moment when the end ST starts the mote month, the Vi(t
) or the potential difference across the capacitor 82 vt (sT).

Clamping gate voltage Vg(t) Vgl)
= v i(shi) −v 1(sv) = 0
te′j, can be obtained.

b) In the 1)n and a half of mote I, the detector is looking at the internal radiation q・1 as in the 13th L's A to B, and almost all Vi (tl is constant and Vg (tl is also almost constant) , if it changes with a slightly positive slope (differential coefficient) as shown in the same figure, the gate is open for the purpose of 61, and v g(t) -v tit) -v 1(s7)
>.

However, if the threshold voltage Vr is not exceeded, the output will fail. It doesn't appear.

That is, vo = O (Vg (t) - Vr = Vi (t) - Vi (5 guns)
-Vr<O) is satisfied.

C) In the second half of Mode I, when the end of the visual field becomes visible (OT from B in Figure 13), if there is no target, the floor becomes visible. Then, V j,(t) changes in the negative direction.

V g(t)=V 1(t)−V i(sT)<
When it becomes 0, the diode 85 becomes conductive and short-circuited;
closes. f21J becomes Vg(t) −0.

d) Mode I ends when it becomes OT, so switch to SWIN-J-
83 opens, the sample value Vi (0) at the time of OT becomes the potential difference between both ends of the content 82, and the gate unconditionally shifts to Ij>J<Mode II. Therefore V
g(t)-vl)-vlk) given by vo #-1 (Vg(t) -Vr -vl(t+-vi(oT)
-Vr≧0)Vo =O (Vg(t) -Vr -Vi(t) -Vi(07)
−Vr<O) under the pulsed condition,
If there is a target, it will be pulsed.

e) C! When it reaches T, mode 11 ends and the mode moves to mode ■J゛. That is, since the switch 84 is closed and an unconditional short circuit occurs, Vg(t,)=Q.

■If the waveform is close to the target or aT (, 1).

a), b) Mode ■1 ends, mode ■11
The process up to the halfway point is exactly the same as a) and b) of ① above.

C) When entering the second half of mode I and seeing the floor, Vi(t
;) changes in the negative direction ・V g(t) −V
1(1;) -V 1(sT) < 0, and the diode 85 becomes conductive and short-circuited, closing the gate. That is, Vg(t) −0.

However, before I became an OT, my goal became clear to me. (1
) begins to change in the positive direction, then Vg) -Vi (tl -Vi(t') > 0, and the value zumbling at the timing of t' is equal to the voltage difference across the capacitor 82 and 4" Due to the action of the diode 85, the gate automatically opens isometrically.

Therefore, Vo=1 (Vg(t)-Vr=Vi(t)-Vi(t')-V
r≧0) Vo=O (Vg(tl −Vr= Vi(shi)−Vi(t’)
It is pulsed under the condition of -Vr <O) and has the effect of the automatic OT described above, so that it can be detected even if there is a target near the OT.

d) When Vi(t) is still in the increasing process, OT
, the potential difference across the capacitor 82 is V i (o
r), the gate remains open at V i (t'), and the operation is the same as in (2) and (a) above. If OT comes after Vi(t) decreases, it will be the same as ■ and e).

e) After CT, it is exactly the same as ``11J description ■, e).

Therefore, even if a target exists before the fixed timing OT, it can be detected and the detection field of view can be widened.

■When the waveform is such that the target is present throughout the field of view.

As for the waveform, B-c-D in FIG. 13 is higher than A-B. In other words, it becomes a passing wave, with a rising waveform of 8-, B-, and C. Is the analog 17 switch 83 closed?Is the gate isometrically open at the timing of ST due to the action of the diode 85 and moves to the mote II? Do J.

The subsequent steps are the same as d) and e) in ■.

As mentioned above, the capacitor 8
It can be realized by a simple combination of 2, analog switch 8, 84 and diode 85.

In the above embodiment, the threshold voltage of the conno cerator 86 is fixed, but it can be automatically adjusted.
It is also possible to eliminate sensitivity unevenness due to fluctuations in ambient temperature.

In addition, in the above explanation, this congestion degree detection device is explained as measuring only people, but it can be measured using a moving car or motorcycle (the humidity of the engine part is sufficiently high compared to the ambient temperature). It can also be applied to measuring traffic volume.

As described below, according to the present invention, the number of people can be measured accurately without being affected by the ambient temperature and without narrowing the detection range, and the circuit configuration is made of extremely simple elements. Since it can be realized by a combination, this congestion degree detection device, which essentially requires a multi-channel signal processing circuit, has a very large effect on miniaturization and economical efficiency.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are diagrams for explaining the scanning method of the congestion level detection device, Figure 2 is a sectional view of the elevator hall, and Figure 6 shows the configuration of the optical system of the congestion level detection device. figure,
Figures 4 (a) and (b) are diagrams showing the distribution of the amount of infrared radiation incident on the detection element, Figure 5 is a diagram showing the conventional circuit configuration of an infrared detection device, and Figure 6 is a diagram showing the main amplifier. A diagram showing the conventional circuit configuration of the circuit group, Figures 7 (a) to (c) are diagrams explaining how to obtain a signal corresponding to the number of people in the field of view from the output of the detection element, and Figure 8 is a diagram showing the digital multi Figure 9 is a diagram showing the circuit configuration of the breaker circuit, Figure 9 is a diagram showing the circuit tj/7 configuration of the synchronous circuit, Figures 10 (a) to (n) are time charts of each signal, and Figure 11 is the diagram of the scanning mirror. 12 is a diagram showing a part of the circuit configuration of the mixing degree detection device according to the present invention; FIG. 13 is a diagram showing the relationship between the signal waveform and each timing; FIG. (a) to (d) are diagrams showing the relationship between operation modes and timing pulses. 1.15. ,, Scanning mirror 2, 19 Lens filter, 18
a-18e, Detection element 5.14. , Infrared 16, Waiting for customers 20,...
Preamplifier group 210. Bandpass filter circuit group 224. Main amplifier circuit group 233. Digital multiplexer circuit 24...
il number circuit 251. Output device 26, synchronous circuits 62', 66', medium stable multi-vibration break 81,
Buffer amplifier 82, capacitor 83.84. ,. Analog switch 85, diode 86, converter 8
7. Voltage setting volume special d1 Applicant: Fujichik Co., Ltd. Figure 1 (α) Neck 1 Dog meeting Ib) Image #Matakai No. 2 Mouth 47 3 Figure 8 (4-glance procedure correction writing method) % formula % Display of 1 item 1988 Patent Application No. 192763 2 Name of the invention Crowd level detection device 3 hti City person/if Relationship with fT 1 system Patent applicant 11i ! (Flight number 550

Claims (1)

[Claims] A detection element that responds to changes in incident infrared rays, a scanning mirror that rotates at a constant cycle, and a synchronization circuit that sets the field of view of the detection element in synchronization with the scanning mirror, and detects the area within the field of view from the output signal of the detection element. In an apparatus for counting the number of people or determining the degree of congestion, means for holding a sample value of the output signal at either a fixed timing or a timing corresponding to a point of change in the sign of the output signal; A crowding degree detection device comprising means for generating an output when a difference from the sample value exceeds a predetermined value, and obtaining a signal corresponding to the number of people within the field of view.