JPH07270545A - Human body detection device - Google Patents

Abstract

(57) [Summary] [Purpose] Even if the temperature of the detection area changes or the human body stands still in the detection area, it is possible to accurately determine the presence or absence of the human body. When a human body detection is judged to be performed by the fact that the differential output level output from the differential output means 3 exceeds a predetermined threshold value set in advance, a human body detection signal is preset every time the judgment is made. While continuously outputting for one off delay time, the addition output level output from the addition output means 5 within the first off delay time is a predetermined level or more than the addition output level before the human body detection signal is output. When the height is high, the control means 6 is provided to control so that the output of the human body detection signal is continued for a preset second off-delay time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to applications such as determining the presence of a human body by detecting infrared rays emitted from the human body and controlling on / off of a desired device such as a lighting device accordingly. To an improved human body detection device.

[0002]

2. Description of the Related Art As a human body detecting device of this type, for example, a type using a pyroelectric element as an infrared detecting element is known. Since this pyroelectric element outputs an electric signal of a level corresponding to the change in temperature, when the human body is operating, such as when the human body passes through the detection area, proper human body detection is possible. It is possible. However, when the human body does not move in the detection area and stands still, or when the amount of movement is small, it becomes difficult to detect the temperature change due to the human body movement. Therefore, in such a case, there is a problem that the load of the lighting equipment or the like is unduly turned off, even though the human body exists in the detection area.

Therefore, conventionally, the infrared detecting element of the pyroelectric element type as described above is not used, but an infrared detecting element having a so-called DC output characteristic such as a thermopile, a thermistor, and a porometer is used. Attempts have also been made to perform detection. As shown in FIG. 11, the electric signal output by the infrared detector 2e receiving the infrared light and amplified by the amplifying unit 80 is compared with the reference voltage value generated by the reference voltage unit 82. This is a method of making comparison at 81. The reference voltage unit 82 is set to output a reference voltage value corresponding to an electric signal output by the infrared detection element 2e when infrared rays are received from the background portion of the detection area, and the electric signal from the infrared detection element 2e is set. Is higher than the level of the reference voltage by a certain amount or more, it is configured to judge that a human body exists.

[0004]

However, in the above-mentioned conventional device, the reference voltage output from the reference voltage unit 82 is fixed and set to a predetermined constant value, so that the background temperature of the detection region changes. When such a situation occurred, it was no longer possible to accurately determine the presence or absence of the human body. That is, in the related art, for example, if the background temperature of the detection area rises for some reason, the output value of the signal output from the infrared detection element 2e becomes large even if no human body is present in the detection area, There was a situation where the human body was mistakenly judged to exist. On the contrary, even when the human body is present in the detection area, if the human body moves in the detection area and the amount of energy incident on the infrared detection element 2e fluctuates significantly, In some cases, it was mistakenly determined to be absent. As described above, conventionally, the human body detection judgment is not accurate and its reliability is very low.

The present invention has been proposed in view of the above points, and determines whether or not a human body is present even when the temperature of the detection area changes or the human body stands still in the detection area. The purpose is to be able to make accurate decisions.

[0006]

SUMMARY OF THE INVENTION A human body detecting apparatus according to the present invention, which is proposed to achieve the above object, is for forming a constant detection area in which a plurality of detection beams are present. Infrared detection having a condenser lens and a plurality of light receiving surfaces for receiving infrared rays condensed through the condenser lens and outputting an electric signal of a level according to the amount of infrared rays received by each of the light receiving surfaces. A human body detection device including an element, and differential output means for performing differential output corresponding to a difference in level between two types of positive and negative electric signals output from a plurality of light receiving surfaces of the infrared detection element; An addition output means for performing addition output of electric signals output from a plurality of light receiving surfaces of the infrared detection element, and a differential output level output from the differential output means exceeding a predetermined threshold value. To detect human body When the determination is made, the human body detection signal is continuously output for the preset first off-delay time each time the determination is made, and the addition output level outputs the human body detection signal within the first off-delay time. And a control means for controlling so as to extend and continue the output of the human body detection signal for a preset second off delay time when the output level is higher than the previous addition output level by a predetermined level or more. ing.

According to a second aspect of the present invention, in the human body detecting device according to the first aspect of the invention, instead of the differential output means and the addition output means, output is made for each light receiving surface of the infrared detection element. Control means for calculating the differential output value and the addition output value based on the electric signal.

[0008]

In the human body detecting apparatus according to the present invention as set forth in claim 1, when the human body first enters the detection area and the detection beam in the detection area is blocked, the detection beam is detected. The difference between the value of the electrical signal output from the light receiving surface where the light is blocked and the value of the electrical signal output from the light receiving surface where the detection beam is not blocked increases, and the differential output is output from the differential output means. The level increases. Then, when the differential output level exceeds a predetermined threshold value and the control means determines that the human body is detected, the output of the human body detection signal is started at this point. That is, the output start of the human body detection signal depends only on the differential output level, and the output of the human body detection signal is not started by the change of the addition output level. Therefore, it is possible to prevent the human body from being erroneously determined to exist due to a change in the background temperature of the detection area, etc., even though the human body has not entered the detection area.

Next, the human body detection signal is continuously output for a preset first off-delay time,
When a human body is present in the detection area during this period, the amount of infrared light received by the infrared detecting element increases by the amount of the human body, and the addition output level output from the addition output means becomes higher than a certain level. And in this case,
The output time of the human body detection signal is extended by the second off-delay time and continuously output. Therefore, even if the human body that has entered the detection area is stationary within the detection area, the human body detection signal output will continue appropriately as long as the presence of the human body increases the amount of received infrared light. It The output of the human body detection signal is not immediately stopped by the human body resting.

In the human body detecting apparatus according to the present invention as defined in claim 2, the control means calculates the differential output value and the addition output value based on the electric signal output for each light receiving surface of the infrared detecting element. The human body detection signal is calculated and the same human body detection signal output processing as in the case of claim 1 is executed based on the calculated differential output value and added output value.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of a hardware configuration of a human body detection device according to the present invention. The human body detection device A includes a condenser lens 1, an infrared detection element 2 that outputs an electric signal (infrared detection signal) having an output level corresponding to the amount of received infrared light, and a differential circuit that performs a differential output described below from the infrared detection signal. 3, a bandpass filter circuit 4 for removing unnecessary frequency components in the signal output from the differential circuit 3, an adder circuit 5 for performing an addition output described later from the infrared detection signal, a CPU corresponding to the control means according to the present invention, and the like. And a signal processing unit 6 configured as described above, and an output control unit 7 that outputs a relay signal for performing on / off control of a desired device such as a lighting fixture.

Of the above, the condenser lens 1 is shown in FIG.
A dome-shaped lens as shown in (a) and (b),
The spherical surface is divided into, for example, 16 so as to constitute a so-called Fresnel lens array in which a total of 16 Fresnel lens arrays 10 for collecting infrared rays are connected in series. The material of each Fresnel lens 10 is, for example, polyethylene resin, and the thickness thereof is, for example, 0.8 [mm].
The infrared rays transmitted through each lens are suppressed from being attenuated by being made constant. The focal length of each of these Fresnel lenses 10 is set to, for example, 14.5 [mm].

As the infrared detecting element 2, for example, a so-called four-element type DC output type infrared detecting element having four light receiving surfaces 20 (20a to 20d) as shown in FIG. 3 is applied. As the DC output type, a thermopile, a thermistor, or a porometer type infrared detecting element is applicable. Each light receiving surface 20 of the infrared detecting element 2
Is to individually output an electric signal (infrared detection signal) having a voltage level corresponding to the amount of received infrared rays. That is, when infrared rays are received by each light receiving surface 20 and the temperature thereof rises, an electric signal of a voltage level corresponding to the temperature rise is output. As a specific size of each light receiving surface 20, for example, the dimension S of one side is 1.1 [mm],
The mutual dimension Sa is set to 1.5 [mm]. still,
Around the light-receiving surface 20, a total of four temperature-compensating light-receiving surfaces 21 are hidden by the visual field frame 22 so as not to receive infrared rays from the detection area. These temperature compensating light receiving surfaces 21 are for detecting the ambient temperature of the infrared detecting element 2.

By using the infrared detecting element 2 and the condenser lens 1 described above, the human body detecting device K according to the present embodiment has the structure shown in FIG.
As shown in (a) and (b), it is possible to obtain a detection area A in which a plurality of detection beams b are arranged at regular intervals. As a specific example of this, when the human body detection device K is mounted downward on a ceiling surface having a height H from the floor surface of 2 [m], the width Sb of each detection beam b formed on the floor surface is approximately The distance between the detection beams b can be set to about 20 cm, and the distance between the detection beams b can be set to be substantially equal to that.

Further, in FIG. 4A, the electrical characteristics of the detection beams b, b adjacent to each other are described as "+" and "-", which are different from each other, but this difference will be described later. It shows the electrical characteristics of the detection beam b when obtaining a dynamic output. That is, in this state, when the human body blocks the “+” detection beam b, the light receiving surface 2 corresponding to the detection beam b is detected.
When the human body detection signal of positive voltage is output from 0 and the detection beam b of “−” is blocked, the human body detection signal of negative voltage is output from the light receiving surface 20 corresponding to the detection beam b. .

As shown in FIG. 5, the differential circuit 3 includes two light receiving surfaces 2 out of the four light receiving surfaces 20 (20a to 20d).
When the human body detection signals output from 0a and 20c have an electric characteristic of "-" and the human body detection signals output from the other two light receiving surfaces 20b and 20d have an electric characteristic of "+", these positive and negative A differential output corresponding to the level difference of the human body detection signal is performed. This differential output is
Since it is weak as it is, an amplifier circuit (not shown) for amplifying it is also provided in the differential circuit 3.

As shown in FIG. 6, the adder circuit 5 makes all the human body detection signals output from the four light receiving surfaces 20 (20a to 20d) have "+" electric characteristics, for example. The addition output corresponding to the total value of the detection signals is performed. The adder circuit 5 is also provided with an amplifier circuit for amplifying the added output.

The value of the addition output output from the adding circuit 5 has a property of being influenced by the ambient temperature. For example, when the ambient temperature rises, the value of the addition output also increases. Therefore, as a means for eliminating such difficulties and performing temperature compensation,
For example, it is desirable to have a configuration as shown in FIG. That is, the configuration shown in FIG.
By inputting both the signal output from the adder circuit 5 connected to 0 and the signal output from the temperature compensating light-receiving surface 21 to the differential amplifier 50, a value corresponding to the difference is added. It is configured to be output as an output signal. With this configuration, a signal of a level corresponding to the ambient temperature is output from the temperature compensating light receiving surface 21, and a signal having a value corresponding to the difference between this signal and the signal output from the adding circuit 5 is output to the differential amplifier. Since it is output from 50, an addition output signal that is not affected by changes in ambient temperature can be obtained.

The signal processing unit 6 is composed of, for example, a CPU and the like, and determines the presence / absence of human body detection based on the signals of the differential output from the differential circuit 3 and the addition output from the addition circuit 5 described above. It is determined and the output of the human body detection signal to the output control unit 7 is controlled. The signal processing unit 6 determines that a human body is present when the value (absolute value) of the differential output from the differential circuit 3 exceeds a preset positive or negative threshold value VTH1, and detects a predetermined human body. Output a signal. The signal processing unit 6 is
When outputting the human body detection signal, the human body detection signal is continuously output for a preset first off-delay time T1. This first off delay time T1
Is reset each time the value of the differential output exceeds the threshold value VTH1, and is newly timed from that point.

Further, in the signal processing unit 6, the addition output level output from the addition circuit 5 within the first off-delay time T1 becomes higher than the addition output level before the human body detection signal is output by a predetermined level or more. During this time, the human body detection signal is controlled to be extended and continued for a preset second off-delay time T2.

The output control unit 7 is configured to perform a relay output for turning on the lighting fixture, for example, to the lighting fixture only when the human body detection signal is output from the signal processing unit 6. There is.

Next, an example of use and operation of the human body detection device K having the above-mentioned configuration will be described. First, as shown by an arrow a1 in FIG. 8, when the human body M enters the detection area A from the outside of the detection area A, the infrared rays emitted from the human body are blocked by the plurality of detection beams b. Sensing element 2
The light is received by one of the light receiving surfaces 20 of. In this case, there is a large difference between the output value of the infrared detection signal output from the light receiving surface 20 that receives the infrared light from the human body and the output value of the infrared detection signal output from the light receiving surface that does not receive the infrared light. In addition, the value of the differential output from the differential circuit 3 becomes large. As a result, as shown by the arrow N1 in FIG. 9A, the differential output exceeds the predetermined threshold value VTH1. Then, as shown in FIG. 7B, the human body detection signal is output from the signal processing unit 6 when the differential output value exceeds the threshold value VTH1.
The output of the human body detection signal is continuously performed for at least the first off-delay time T1. Also, this first
If the differential output value exceeds the threshold value VTH1 before the off-delay time T1 of 1 has passed, the time of the first off-delay time T1 is updated each time, and the timing is newly started.

Next, the human body M that has entered the detection area A
However, if it stops at the position shown by the arrow a2 in FIG. 8, the differential output value becomes low level as shown by the arrow N2 in FIG. 9A, and this differential output value must exceed the threshold value VTH1. There is no. However, if the human body M exists in the detection area A, the addition output value output from the addition circuit 5 becomes higher than that before the human body M enters the detection area A. Therefore, in this case, as shown in FIG. 9C, the value of the addition output exceeds the predetermined threshold value VTH2. Then,
The signal processing unit 6 extends the output time of the human body detection signal by the second off-delay time T2 in addition to the first off-delay time T1. Therefore, the human body M is in the detection area A
Although it exists inside, the lighting device is not turned off immediately after the lapse of the first off-delay time T1.

As long as the human body M actually exists in the detection area A as described above, the human body M must move in the detection area A after that. Therefore, before the second off-delay time T2 is timed up, for example, as shown in FIG.
When the human body M moves as shown by the arrow a3 in FIG.
As shown by the arrow N3 in (a), the value of the differential output exceeds the threshold value VTH1 again, and the output of the human body detection signal is again extended from that time point by the first off-delay time T1. After the human body M exits the detection area A, the addition output value output from the addition circuit 5 is no longer the threshold value VTH2.
Therefore, in this case, the output of the human body detection signal ends when the first off-delay time T1 is up, and the lighting fixture is turned off.

In the above description, when the second off-delay time T2 is lengthened, the ability to detect the stationary human body M can be improved, but the value of the addition output is reduced due to environmental fluctuations. It may change. Therefore, when determining the second off-delay time T2, it is necessary to consider that the time is not too long. Considering the operating conditions of the human body, the usage environment of the human body detection device K, etc., it is usually about several minutes. Is desirable.

On the other hand, when the first off-delay time T1 is shortened, there is an advantage that the lighting fixture can be turned off immediately after the human body M exits from the detection area A, but
If this time is set too short, it becomes impossible to accurately determine the presence or absence of a human body based on the addition output within the first off-delay time T1. Therefore, it is necessary to set the first off-delay time T1 in consideration of the usage conditions, the surrounding environment, etc., and normally, for example, several tens of seconds to 1 minute is desirable. However, in either case of the first off-delay time T1 and the second off-delay time T2, the specific value of the time is not limited in the present invention.

Further, in the above embodiment, the four light receiving surfaces 20 are provided.
The case where the four-element type infrared detecting element 2 having the above is used has been described as an example, but the present invention is not limited to this. For example, as shown in FIG.
You may use the infrared detection element 2A provided with 0A and 20A. On the contrary, the number of light receiving surfaces may be increased more than that in the above-described embodiment to form a larger number of detection beams in the detection area.

Further, in the above embodiment, the infrared detecting element is connected to the differential circuit and the adding circuit to take out the differential output and the adding output (corresponding to claim 1), but the book according to claim 2 The invention is not limited to this. That is, an electric signal (infrared detection signal) output corresponding to each light receiving surface of the infrared detection element is input as it is to a signal processing unit composed of a CPU or the like, and signal processing is performed based on the level of the infrared detection signal. It does not matter even if the values of the differential output and the addition output are calculated and processed by the software processing of the unit.

[0029]

As can be understood from the above description, according to the human body detection device of the present invention as defined in claims 1 and 2, the output of the human body detection signal is started at the differential output level of the infrared detection element. Therefore, the output of the human body detection signal is not started by the change of the added output level, and the background temperature of the detection area is changed even if the human body does not enter the detection area. It can be avoided that the human body is erroneously determined to exist due to the cause. Also,
Even if the human body that has entered the detection area is stationary within the detection area and the presence of the human body cannot be determined by the differential output, the presence of the human body can be appropriately determined by the addition output, and the movement of the human body can be determined. The output of the human body detection signal is not immediately stopped by stopping the operation. As a result, there is a remarkable effect that the judgment of the human body detection can be made fairly accurately and the reliability thereof can be improved as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a hardware configuration of a human body detection device according to the present invention.

2A and 2B show an example of a condenser lens of a human body detection device according to the present invention, in which FIG. 2A is a plan view and FIG. 2B is a sectional view thereof.

FIG. 3 is an explanatory plan view showing an example of an infrared detection element of the human body detection device according to the present invention.

4A and 4B show an example of a detection region formed by the human body detection device according to the present invention, FIG. 4A is a plan view and FIG. 4B is a side view thereof.

FIG. 5 is an explanatory diagram showing an example of a connection state between an infrared detection element and a differential circuit in the human body detection device according to the present invention.

FIG. 6 is an explanatory diagram showing an example of a connection state between an infrared detection element and an adder circuit in the human body detection device according to the present invention.

FIG. 7 is a block diagram showing a configuration example in the case of performing temperature compensation of an addition output output from an addition circuit.

FIG. 8 is an explanatory diagram showing a state in which a human body enters the detection area.

9 (a) to 9 (e) are time charts showing an operation example of the human body detection device according to the present invention.

FIG. 10 is an explanatory view of a main part showing another configuration example of the human body detection device according to the present invention.

FIG. 11 is a block diagram showing an example of a conventional human body detection device.

[Explanation of symbols]

 1 Condensing Lens 2, 2A Infrared Detector 3 Differential Circuit 5 Adder 6 Signal Processor 7 Output Controller 20 (20a-20d), 20A Light-Receiving Surface 21 Temperature Compensating Light-Receiving Surface b Detecting Beam A Detecting Area T1 1st Off-delay time T2 Second off-delay time K Human detection device

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Claims (2)

[Claims] 1. A condenser lens for forming a constant detection region in which a plurality of detection beams are present, and a plurality of light-receiving surfaces for receiving infrared rays condensed through the condenser lens, A human body detection device comprising an infrared detection element that outputs an electric signal at a level according to the amount of infrared light received on each of these light-receiving surfaces, and a positive / negative output from a plurality of light-receiving surfaces of the infrared detection element.
Differential output means for performing a differential output corresponding to the difference between the levels of two negative electrical signals; and addition output means for performing an additive output of the electrical signals output from the plurality of light receiving surfaces of the infrared detection element; When it is determined that a human body is detected by the fact that the differential output level output from the differential output means exceeds a predetermined threshold value set in advance, a human body detection signal is set to a preset first off-delay every time the determination is made. The output is continued for only the time, and when the addition output level is higher than the addition output level before the human body detection signal is output by a predetermined level or more within the first off-delay time, a preset first 2. A human body detection device, comprising: a control means for controlling the output of the human body detection signal to be extended and continued for an off delay time of 2. 2. The differential output value and the addition output value according to claim 1, instead of the differential output means and the addition output means, based on an electric signal output for each light receiving surface of the infrared detection element. A human body detection device provided with control means for performing arithmetic processing.