JPH063366A - Infrared human body detector - Google Patents

Abstract

PURPOSE:To prevent the occurrence of such a state that the same state as a human body detecting state continues for a long time when a human body leaves a detecting area by comparing a detecting signal outputted from an infrared detecting element with a prescribed threshold. CONSTITUTION:A comparator circuit 5 compares the output level of an infrared detecting signal from a band-pass filter circuit 4 with either one of the two kinds of thresholds respectively set in threshold setting circuits 8a and 8b outputted by means of a change-over switch 10. When the infrared detecting signal exceeds the threshold, an delay circuit 6 delays the outputting timing of the detecting signal by a fixed period of time. When an output control section 7 receives a prescribed signal from the circuit 6, the section 7 outputs a relay signal for turning on lighting equipment. When the reception of continuous output signals from the circuit 6 is discontinued, the section 7 immediately outputs another relay signal for turning off the lighting equipment so as to make an infrared detecting element 2 to discriminate that no human body exists.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects an infrared ray emitted from a human body to detect the presence of the human body, and an infrared type human body detection applied to the purpose of controlling various facilities such as indoor lighting and air conditioning. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, an infrared type human body detecting device of a type using a pyroelectric element as an infrared detecting element has been developed. In this type of human body detection device, unlike a system in which near infrared rays are projected to detect the amount of change in the reflected light, a light emitter is not required, and the conditions of the optical system of the condenser are changed. Since it is possible to easily set different detection areas, it can be used not only for intrusion detection for crime prevention but also for switch control of lighting equipment. However, in the above infrared type human body detection device, since it is a method of capturing a change in temperature with an infrared detection element, although the detection signal can be continuously output when the human body is moving, the human body is in a certain area. If the detection beam of the human body detection device is not blocked because it has stopped or its movement is small,
The desired high-power detection signal can no longer be output. Therefore, there is a possibility that a problem such as turning off the lighting in the room may occur despite the presence of a human body.

Therefore, conventionally, as a measure for solving the above-mentioned problems, when an infrared detection signal for human body detection is once output from an infrared detection element, this signal is expanded and expanded for a certain period of time using a circuit. Therefore, a human body detection state is maintained for a certain period of time so that it is not immediately determined that the human body is absent even if the next detection signal is not output. Further, as another solution, by setting the threshold value for judging whether the infrared detection signal is due to human body detection to be very small, even if the human body is relatively small, There is also proposed a device in which the obtained detection signal of low output level can be judged as human body detection.

[0004]

In the former case, the detection beam is blocked and the detection signal of high output level is not continuously output within the delay time of the detection signal set in the delay circuit. Then, it is determined that the human body does not exist. Therefore, if the delay time of the detection signal is shortened, when the movement of the human body is small, it is determined that the human body does not exist any more in a short time and the illumination is turned off. In order to eliminate this, it is necessary to set the extension time longer, but in that case, even if the human body exits, within the extension time set for a long time after that, It will be judged that the human body exists. As a result, even after the human body exits, the lighting is unnecessarily continued to light for a long time, resulting in considerable waste.

On the other hand, in the latter one of the above-mentioned conventional ones, even if the detection signal has a small output, it is judged that it is a human body detection. However, there is a problem in that the human body detection is often detected, and errors in human body detection occur frequently.

The present invention has been proposed in view of the above points, and when the human body exits the detection area, it is prevented that a state similar to the presence of the human body is detected for a long time. At the same time, it is an object of the present invention to provide an infrared type human body detector capable of eliminating the risk of erroneously determining a low output detection signal as a human body detection signal due to a temperature change in a detection area or the like. .

[0007]

SUMMARY OF THE INVENTION An infrared type human body detector according to the present invention, which is proposed to achieve the above object, receives infrared rays from a detection area and changes the amount of received light. Infrared detection element that outputs a detection signal of an output level according to the minute, and a comparison unit that compares the detection signal output from this infrared detection element with a predetermined threshold value, and a detection signal of an output level exceeding the threshold value is output. If a detection signal with an output level exceeding the threshold value is not continuously output from the infrared detection element within a predetermined fixed time after the operation, it is determined that the human body is absent, and a predetermined signal is output to the outside. In the infrared type human body detector, at least two thresholds of the output level to be compared with the infrared detection signal are set, and it is determined that the human body is absent in the detection area in the normal setting state. , Among the two kinds of thresholds with the threshold of the high output level side it is compared with the infrared detection signal,
After the infrared detection signal exceeding the high output level side threshold value is output, the low output level side threshold value is compared with the infrared detection signal.

In the above-mentioned structure of the present invention, the concrete means for judging that the detection signal of the output level exceeding the threshold value is not continuously output from the infrared detecting element within a predetermined constant time is as follows. According to the second aspect of the present invention, a stretching circuit that stretches and outputs the infrared detection signal having an output level exceeding the threshold value for a certain period of time is provided, and the signal output from the stretching circuit continues. A means for determining that the human body is present at the time and determining that the human body is absent when the signal output is interrupted is applied. As a means different from the second aspect, the present invention, as described in the third aspect, resets the timer circuit each time the infrared detection element outputs a detection signal having an output level exceeding a predetermined threshold value. A means for performing measurement and determining that the human body does not exist when the measurement time reaches a predetermined fixed time is also applicable.

[0009]

In the infrared type human body detector according to the present invention according to claim 1 having the above-mentioned structure, in the normal setting state in which it is determined that the human body is absent in the detection area, the threshold value of the two types is high. The threshold value on the output level side is compared with the detection signal. Therefore, if the threshold value on the high output level side is set to an output level higher than the low output level detection signal output due to, for example, a simple temperature change in the detection area, a simple temperature change other than human body detection, etc. It is possible to avoid determining the detection signal output due to the human body detection signal as the human body detection signal, and appropriately prevent the human body detection error determination.

On the other hand, after the human body has entered the detection area and the infrared detection signal exceeding the threshold on the high output level side is output, unlike the above case, the low output of the two types of thresholds is output. The threshold value on the level side is determined to be an infrared detection signal. With such a threshold value on the low output level side, even if there is little movement of the human body, the operation can cause the infrared detection signal exceeding the threshold value on the low output level side to be frequently output at short time intervals. Therefore, it is possible not only to prevent the human body from being determined to be absent even though the human body is present in the detection area, but also to set the time to determine that the human body is absent due to the interruption of the human body detection signal. Even if is shortened, it is possible to eliminate the possibility that the human body is determined to be absent as long as the human body exists in the detection area and is performing some movement. As a result, after the human body actually exits from the detection area, it can be determined in a short time that the human body is absent.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an infrared human body detector K according to the present invention.
3 is a block diagram showing an example of the hardware configuration of FIG. The infrared type human body detector K shown in the figure is an infrared detecting element 2 which receives infrared rays through a condenser 1 such as a Fresnel lens, and an amplification section which amplifies an infrared detecting signal output from the infrared detecting element 2. 3. A bandpass filter circuit 4 for removing unnecessary frequency components from the detection signal amplified by the amplification unit 3 is provided. Further, in addition to them, in the subsequent stage of the bandpass filter circuit 4, the comparison circuit 5, the extension circuit 6, the output control unit 2, and the threshold value setting circuits 8a and 8 that can set two threshold values.
b, a threshold value selection processing unit 9 and the like are also provided.

Among the above-mentioned units, as an example of the infrared detecting element 2, a type using a pyroelectric element whose voltage value changes by receiving infrared rays is applied, and an output level corresponding to a change in the amount of infrared rays received. It is configured to output the detection signal of. The infrared detection element 2 and the condenser 1 are
It is preferable that a large number of detection beams are obtained in the detection region with a narrow pitch.

The threshold value setting circuits 8a and 8b are for setting two kinds of threshold values H and L whose output levels are different from each other. As the threshold value H on the high output level side, the detection beam of the infrared detecting element 2 is detected by the human body. Is slightly lower than the output level of the infrared detection signal output from the band-pass filter circuit 4 when it is blocked, but higher than the output level of the detection signal output due to a rapid temperature change in the detection area. The value applies. On the other hand, a value lower than the threshold value H on the high output level side is applied as the threshold value L on the low output level side, but is output when an appropriate operation is performed in a state where the human body remains in the same place. A value slightly lower than the output level of the detection signal applies. The threshold value setting circuits 8a and 8b are configured so that desired specific values can be arbitrarily set as the two kinds of threshold values H and L, and preferably the values can be appropriately increased or decreased.

The comparison circuit 5 includes the threshold value setting circuits 8a and 8a.
Of the two types of threshold values set in b, the changeover switch 10
This compares one of the threshold values switched and output with the output level of the infrared detection signal output from the band-pass filter circuit 4. When the infrared detection signal exceeds a predetermined threshold as a result of the comparison in the comparison circuit 5, the extension circuit 6 outputs the detection signal for a predetermined time T.
It is for extending and outputting only. When the output control unit 7 receives a predetermined output signal from the extension circuit 6, the output control unit 7 outputs a relay signal for turning on a lighting fixture as an example of a controlled object, while continuing from the extension circuit 6. When the reception of the output signal is interrupted, a relay signal for turning off the lighting fixture is output at that time. That is, the infrared type human body detector K according to the present embodiment.
Judges that the human body exists in the detection area when there is a continuous signal output from the extension circuit 6, but when the signal output is interrupted, the human body exits the detection area at that point and the human body becomes absent. It is configured to judge that it has become.

The threshold value selection processing unit 9 selects from the two threshold value setting circuits 8a and 8b so that the threshold value H or L on the appropriate side of either one is inputted to the comparison circuit 5. That is, the threshold value selection processing unit 9 first selects the high output level side threshold value H set on the one threshold value setting circuit 8a side in the normal setting state in which it is determined that the human body is not present in the detection area. In such a state, when the infrared detection signal exceeding the threshold value is output, the changeover switch 10 is set so as to select the low output level side threshold value L set on the other threshold value setting circuit 8b side at that time. Switching control is performed. Further, in the state where the threshold L on the low output level side set on the side of the other threshold setting circuit 8b is selected, when the continuous signal output from the extension circuit 6 is interrupted, the original threshold setting circuit The switching control is performed so as to select the high output level side threshold value H set on the 8a side.

Next, the operation of the infrared type human body detector K having the above structure will be described. First, in use, as shown in FIG. 2, for example, the infrared type human body detector K is attached to the ceiling surface of the room or the like, and is set so that the detection beam b can cover substantially the entire area of the room. Further, a relay signal can be transmitted from the output control unit 7 of the human body detector K to a relay (not shown) of the power switch of the lighting fixture R which is an on / off control target.

After the above setting, in the initial state when the human body is detected, one of the two threshold value setting circuits 8a and 8b is selected and the threshold value input to the comparison circuit 5 is selected. High output level side is selected.
Therefore, in the state where there is no person in the detection area, even if a temperature change occurs in the detection area, the detection signal output from the infrared detection element 2 is as shown in FIG.
As indicated by A in (a), the output is low and does not exceed the threshold value H on the high output level side. Therefore, in the normal time when the threshold value H on the high output level side is selected and compared with the infrared detection signal, a detection signal based on a mere change in room temperature other than human body detection is erroneously determined as a human body detection signal. There is no fear.

Next, in the above state, when a person actually enters the detection area and interrupts the detection beam,
As indicated by B in (a), an infrared detection signal exceeding the threshold value H on the high output level side is output. Therefore, at that point, the signal output from the extension circuit 6 is started, so that the output control unit 7 outputs a relay signal for turning on the lighting fixture R as shown in FIG. The luminaire R is turned on.

At the same time as the above, the threshold selection processing unit 9
Switches the changeover switch 10 to select the other threshold value setting circuit 8
The threshold value L on the low output level side on the b side is selected, and this threshold value is used as a comparison target of the detection signal hereafter. Therefore, even if the human body that has entered the detection area does not move much in the room thereafter and the operation is small, as shown by C1 to C3 in FIG. , The threshold L on the low output level side is exceeded, and human body detection can be appropriately performed. The signal output from the delay circuit 6 is such that the intervals t1, t2, ... Between the output timings of the respective detection signals in C1 to C3 in FIG. As long as it is, the state continues as shown in FIG. Therefore, the human body exists in the room, and
Although the detection signals C1 to C3 in (a) are output, it is not determined that the human body is absent.

On the other hand, in the above state, when the human body goes out of the room, once the detection signal of the high output level as shown by D in FIG. 3A is once output, the detection signal exceeding the threshold of the low output level is output. Will no longer be output continuously. Then, the signal output from the extension circuit 6 is D
After the output of the detection signal of 1), the operation is interrupted when a predetermined extension time T has elapsed. As a result, the output control unit 7 outputs a relay signal for turning off the lighting fixture R, and the light is appropriately turned off.

As described above, the extension time T in the extension circuit 6 is, as described above, the extension signal of the detection signal which is frequently detected at a short time when the human body is present. A short time without interruption will be sufficient. Therefore, if the extension time T is set to a short time, the time until the lighting fixture R is turned off after the human body exits,
Similarly, it can be made very short. Incidentally, after the signal output from the delay circuit 6 is interrupted after the human body exits, the threshold value selection processing unit 9 again selects the high output level side threshold value H to restore the original initial state. Therefore, it is possible to prevent the detection signal of the low output level other than the human body detection from being mistakenly determined as the human body detection after that.

In the above embodiment, it is determined that the human body is absent when the signal output from the extension circuit 6 is interrupted (corresponding to claim 2). For example, when the timer circuit is reset each time a detection signal that exceeds the threshold value is output, the subsequent time measurement is performed, and the next detection signal is not output while the timer circuit or the like measures a predetermined fixed time. May determine that the human body is present (claim 3).
Corresponding to). Further, in the above-described embodiment, the threshold value is set by the threshold value setting circuits 8a and 8b, and the value set there is hard-processed so as to be input to the comparison circuit 5. However, the present invention is not limited to this. Not limited to. For example,
The setting of the two types of threshold values and the comparison processing of the output levels may be processed by a software program using a signal processing means using a CPU or the like.

[0023]

As can be understood from the above description, according to the infrared type human body detector of the present invention, the movement of a small amount of human body is detected by the threshold value on the low output level side among the threshold values of high and low. Since it is possible to judge, it is possible to shorten the set time for judging that the human body is absent by interrupting the output of the detection signal, and judge that the human body is absent after the human body exits the detection area. Therefore, it is possible to shorten the time until the start of the operation, and as a result, it is possible to obtain a special effect that it is possible to eliminate waste such as that the lighting equipment keeps lighting for a long time after leaving the human body. Moreover, according to the present invention, in a state other than the human body detection, in order to compare the threshold value on the high output level side with the infrared detection signal, it is caused by a temperature change in the detection area other than the human body detection, for example. There is also an advantage that it is possible to eliminate the possibility of erroneously determining a detection signal of a low output level as human body detection, and to improve the reliability of human body detection.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing an example of a usage state of an infrared human body detector according to the present invention.

FIG. 3 is a time chart showing various output signals in the infrared type human body detector according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Condenser 2 Infrared detecting element 5 Comparison circuit 6 Extending circuit 7 Output control section 8a, 8b Threshold setting circuit 9 Threshold selection processing section K Infrared human body detector R Lighting fixture

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[Procedure amendment]

[Submission date] June 3, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

On the other hand, in the above state, when the human body goes out of the room, once the detection signal of the high output level as shown by D in FIG. 3A is once output, the detection signal exceeding the threshold of the low output level is output. Will no longer be output continuously. Then, the signal output from the extension circuit 6 is D
After the output of the detection signal of 1), the operation is interrupted when a predetermined extension time T has elapsed. As a result, the output control unit 7 outputs a relay signal for turning off the lighting fixture R, and the light is appropriately turned off. The human body is outdoors
High if the human body moves a lot in the room before leaving.
The output level detection signal may be output, but
The threshold value on the L side should be exceeded regardless of the output level of the intelligent signal.
If there is no signal for T seconds, the threshold level is L side
Since the configuration is selected from the H side to
If a high output level detection signal is output
Even if the threshold level is switched from L side to H side immediately
There is no such thing.

Claims (3)

[Claims] 1. An infrared detection element that receives infrared rays from a detection area and outputs a detection signal of an output level corresponding to a change in the amount of received light, and a detection signal output from the infrared detection element to a predetermined threshold value. A detection means having an output level exceeding the threshold value within a fixed time after the detection signal is output, while determining that a human body exists when a detection signal having an output level exceeding the threshold value is output. If the human body is absent when is not continuously output, it is an infrared type human body detector configured to output a predetermined signal to the outside, and an output level threshold value to be compared with the infrared detection signal. In the normal setting state in which at least two types are set and the human body is judged to be absent in the detection area, the threshold on the high output level side of the two types of thresholds is the infrared detection signal. In addition to being compared, after the infrared detection signal exceeding the high output level side threshold value is output, the low output level side threshold value is compared with the infrared detection signal. Infrared type human body detector. 2. An expansion circuit for expanding an infrared detection signal having an output level exceeding a threshold value for a fixed time and outputting the infrared detection signal, wherein the signal is continuously output from the expansion circuit. An infrared human body detector characterized by being configured to judge that a human body is present and, when the signal output thereof is interrupted, to judge that the human body is absent. 3. A timer circuit is reset each time an infrared detection element outputs a detection signal having an output level exceeding a predetermined threshold value, and time measurement is performed. The measurement time reaches a predetermined constant time. An infrared human body detector characterized in that it is configured to judge that a human body does not exist at the point of time.