JPH0337234B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to situations where the number and position of people in a limited space such as an elevator car is detected using a pyroelectric infrared sensing element. This invention relates to improvements in monitoring equipment.

[Description of prior art and problems]

Patent application 1986-107303 ``Situation monitoring device'' as a device that detects the number and position of people within a limited range by pinhole scanning using a pyroelectric infrared sensing element
There is.

First, the above-mentioned situation monitoring device will be explained.

The situation monitoring device includes a fixed slit for setting the field of view, a rotary plate having a slit that intersects the fixed slit, and a detection element (pyroelectric infrared detection element) that outputs a signal in response to changes in incident infrared rays.
and a signal processing section that processes the output signal of the detection element to determine the number and position of people.

The pinhole is formed at the intersection of the fixed slit and the slit of the rotary plate, and scanning is performed by rotating the rotary plate.

In addition, to divide the field of view, multiple fixed slits are provided, and the slits corresponding to each fixed slit are placed on the rotary plate at different positions, so that the timing of pinhole scanning is different for each field of view. Detection of each field of view is performed using .

FIG. 1A is a diagram showing the appearance of one embodiment of the sensing section of the situation monitoring device. In the figure, 1 is the entire sensing section, 2 is a case, 3 is a rotating plate attached to the front of the case 2, It is driven at a constant speed by a scanning motor (not shown). The rotating plate 3 has slits S1A to S1C.
and S2A to S2C are provided, and play a role as a reticle plate.

FIG.
LA to LC are provided, and as the rotating plate 3 rotates, the slits S1A and S2A change to the slit LA.
Similarly, slits S1B and S2B intersect with slit LB, and slits S1C and S2C intersect with slit LC. 4 is a detection element fixed inside the case 2. In addition, rotating plate 3
Although the reticle plate is shown attached to the outside of the case 2 for convenience of explanation, it is actually preferable to attach it to the inside of the case 2 for reasons of design and the like.
Furthermore, the number of sensing elements 4 may be one, but the number corresponding to each slit may be attached.

FIG. 2 is a partially enlarged view of FIG. 1, showing how pinholes are formed by the intersection of the slits. Here, a pinhole P formed by the slits LA and S1A is shown, and as the rotary plate rotates in the direction of the arrow, the pinhole P moves from the left end to the right end of the slit LA. Similarly, pinholes are sequentially formed in the slits LB and LC, which move as the rotary plate 3 rotates.

FIG. 3 is a diagram showing, as an example, a state in which the sensing section is attached to the ceiling of the car. 5 is an elevator car, and here the field of view is divided into three fields of view, A to C zones, and each zone is further divided into three zones, A to C, by a synchronization signal, which will be described later.
It is divided into 9 sections in total. A
The three divisions of zones a to c are determined by the distance between the slit LA and the sensing element 4 and the size of the slit LA, and similarly, the B zone is defined by the slit LB.
The c zones are respectively set by the slits LC. When the rotary plate 3 rotates, zones A to C are sequentially scanned by the movement of the pinhole, and in this example, each zone is scanned twice in one rotation of the rotary plate 3.

Figure 4 shows the relationship between the scanning position for each zone in one scan and the waveform of the output signal of the detection element 4 over time on the horizontal axis, and A indicates the division of each zone. , b shows an example of the waveform of the output signal of the sensing element. Hall is a synchronization signal corresponding to each section, and since the rotary plate 3 rotates at a constant period, these signals can be easily obtained using, for example, a photo interrupter and a timer.

Note that t ₁ is the point at which scanning of the A zone starts, that is, the point where slits S1A and LA begin to intersect, and t ₂ is the point at which the A zone begins to intersect.
At the end of zone scanning, that is, at slit S1A
and LA end their intersection, respectively, and
Similarly, t ₃ and t ₄ indicate the scanning period of the B zone, and t ₅ and t ₆ indicate the scanning period of the C zone.

Here, the output waveform of the detection element is a of the A zone.
The waveform is shown when there is one person in section b and two people in section b of zone B. As shown in the figure, when two people are in close proximity, the output of the detection element is approximately 2h, which is approximately twice as large as h when there is only one person, so it is necessary to set an appropriate threshold value. It is possible to determine whether there are people present or not, and to determine whether there are one person or two people, and furthermore, by performing an AND with each of the synchronization signals, a signal corresponding to the number of people in each section can be obtained.

In this way, the situation monitoring device described above can detect the number and location of people within a limited range, but if a normal single element is used as the detection element, external vibrations and changes in ambient temperature can be detected. Because it is greatly affected by
The detection accuracy was not fully satisfactory.

[Means for solving problems]

The present invention was made to solve the above problems, and uses dual elements connected in series and with opposite polarities as detection elements, and the sensitivity characteristics and resolution vary greatly depending on the arrangement of the dual elements. Focusing on this, the present invention is characterized in that the dual elements are not arranged at right angles to the scanning direction, but are arranged at an angle from the scanning direction that corresponds to the length of the dual elements and the facing interval.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in comparison with a conventional one.

FIG. 5 is a diagram showing the relationship between the arrangement of the elements and the output voltage when a single element is used as the detection element, and A shows the relationship between the single element 4 arranged on the substrate 6 and the scanning direction; B shows the output voltage waveform of element 4 when one person stands within the field of view in state A, and C shows the output voltage waveform when two people stand side by side within the field of view in state A. This is what is shown. If two people are standing side by side without touching each other, the width of the waveform will be approximately twice that of one person, so if you set the threshold value Th appropriately and detect the width of the waveform, you can detect the difference between one person and two people. can be distinguished.

6 to 8 illustrate the present invention and show the case where the sensing element is a dual element. Similarly to FIG. 5, A shows the relationship between the arrangement of the elements and the scanning direction.
B shows the output voltage waveform in the case of one person, and C shows the output voltage waveform in the case of two people. Since element 4a and element 4b are connected in series with opposite polarity,
When both elements 4a and 4b are arranged facing each other parallel to the scanning direction as shown in Fig. 6A, the output voltages of both elements cancel each other out, and the output voltage waveforms are as shown in Fig. 6B and C. becomes very small. However, as shown in FIG. 7A, elements 4a, 4
When b are placed facing each other at right angles to the scanning direction,
Scanning creates a phase difference between the output voltages of both elements,
The output voltage waveform, which is the sum of these, is as shown in FIG. 7 (b) and (c). Using dual elements in this way provides superior resolution compared to single elements, but experiments have revealed that the sensitivity characteristics and resolution can be further improved by changing the arrangement of the elements.
In other words, the sensitivity characteristics and resolution are greatly affected not only by the size of the dual element and the distance between the elements, but also by the inclination of the element arrangement with respect to the scanning direction. As a result of experiments, it was found that the best characteristics were obtained when θ=tan ⁻¹ a/b, where θ is the inclination of the element with respect to the scanning direction. For example, if a=1 mm and b=2 mm, the optimum inclination θ is tan ^-1 1/2≈30°.

FIG. 8 shows an example of the arrangement of elements when the elements are tilted with respect to the scanning direction, and the state of the output voltage waveform at that time. As is clear from FIG. 8, if the arrangement of the elements is inclined with respect to the scanning direction, the resolution becomes even better.

〔Effect of the invention〕

According to the present invention, the sensitivity characteristics and resolution of the detection element are greatly improved, and the degree of influence from external vibrations and fluctuations in ambient temperature is reduced, so that the detection accuracy is greatly improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the external appearance of the sensing section of the situation monitoring device, FIG. 2 is a partially enlarged view of FIG. Figure 4 is a diagram showing an example of the relationship between the scanning position for each zone and the waveform of the output signal of the detection element, Figure 5 is a diagram showing the relationship between the arrangement of a single element and its output signal waveform, and Figure 6 ~FIG. 8 is a diagram showing the relationship between the arrangement of dual elements and their output signal waveforms. 1... Sensing section, 4, 4a, 4b... Detecting element, 6...
Substrate, P...pinhole, a...distance between elements, b...
Length of the element, θ...Inclination of the element with respect to the scanning direction.

Claims (1)

[Claims] 1. A fixed slit for setting a field of view, a rotary plate having a slit intersecting the fixed slit, means for driving the rotary plate, and outputting a signal in response to changes in incident infrared rays. In the situation monitoring device, the situation monitoring device includes a detection unit including a detection element, and a signal processing unit that determines the number of people and positions within the field of view based on the output signal of the detection element, wherein the detection elements are arranged facing each other at a distance a. A dual element in which two elements of length b are connected in series and with opposite polarity, and the dual elements are arranged so that the facing directions of the dual elements are tilted by approximately θ=tam ^-1 a/b with respect to the scanning direction. A method for arranging elements in a situation monitoring device characterized by: