JP2852582B2 - Infrared human body detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared type human body detection system which detects the presence of a human body by detecting infrared rays emitted from the human body and controls various facilities such as indoor lighting and air conditioning. Related to the device.

[0002]

2. Description of the Related Art Conventionally, an infrared type human body detecting apparatus of the type using a pyroelectric element as an infrared detecting element has been developed. This type of human body detection device does not require a light emitter and changes the conditions of the optical system of the light collector, unlike the method of projecting near-infrared rays and detecting the amount of change in the reflected light. Thus, different detection areas can be easily set, so that the present invention can be used not only for security intrusion detection but also for switch control of lighting equipment. However, in the infrared type human body detection device, since the change in temperature is detected by the infrared detection element, the detection signal can be continuously output when the human body is moving, but the human body is in a certain area. If the detection beam of the human body detection device is not interrupted because it stops or its movement is small,
It is no longer possible to output a desired high output detection signal. Therefore, there is a possibility that a problem such as turning off the lighting in the room may occur even though a human body exists.

Conventionally, as a measure to solve the above-mentioned problem, when an infrared detection signal is once output from the infrared detection element by the human body detection, this signal is extended for a certain period of time by using an extension circuit. As a result, there has been proposed an apparatus in which the 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. Another solution is to set a very small threshold value for determining whether the infrared detection signal is based on human body detection. There has also been proposed one in which the obtained low output level detection signal can be determined as human body detection.

[0004]

In the above-mentioned prior art, the detection beam is interrupted within the extension time of the detection signal set in the extension circuit, so that the high output level detection signal is not continuously output. It is determined that the human body does not exist. Therefore, if the extension 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 lighting is turned off. In order to solve this, it is necessary to set the extension time longer, but in such a case, even if the human body leaves, within the extended extension time set thereafter, It is determined that a human body exists. As a result, even after the human body has left, the illumination is kept on for a long time unnecessarily, resulting in considerable waste.

On the other hand, in the latter conventional one, even if the detection signal has a small output, the detection signal is determined to be a human body detection. However, it is determined that the human body is detected, and there is a problem that errors in the human body detection frequently occur.

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above points, and prevents a situation where the presence of a human body is detected from continuing for a long time when the human body moves out of the detection area. In addition, it is an object of the present invention to provide an infrared human body detector that can eliminate the possibility of erroneously determining a low output detection signal caused by a temperature change or the like in a detection area as a human body detection signal. .

[0007]

According to the first aspect of the present invention, there is provided an infrared human body detector according to the present invention, which receives infrared light from a detection area and changes the amount of received light. An infrared detection element that outputs a detection signal of an output level corresponding to the minute; and a comparing unit that compares the detection signal output from the infrared detection element with a predetermined threshold, and outputs a detection signal of an output level exceeding the threshold. When a detection signal having an output level exceeding the threshold is not continuously output from the infrared detecting element within a predetermined time after being performed, it is determined that a human body is absent and a predetermined signal is output to the outside. In the infrared human body detector, at least two types of output level thresholds to be compared with the infrared detection signal are set, and in a normal setting state where it is determined that a human body is not present in the detection area. , 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 threshold is output, the low output level threshold is compared with the infrared detection signal.

[0008] In the configuration of the first aspect of the present invention, as a specific 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 period of time, Has a stretching circuit for extending and outputting an infrared detection signal having an output level exceeding a threshold for a predetermined time as described in claim 2, and the signal output from the stretching circuit is continued. At this time, means for determining that a human body is present and applying means for determining that the human body is absent when signal output is interrupted are applied. Further, as another means different from the second aspect, the present invention provides a method of resetting a timer circuit by resetting a timer circuit every time a detection signal having an output level exceeding a predetermined threshold is output from an infrared detecting element. Means for performing measurement and determining that a human body does not exist when the measurement time reaches a predetermined fixed time is also applicable.

[0009]

In the infrared human body detector according to the present invention having the above-mentioned configuration, in the normal setting state in which a human body is determined to be absent in the detection area, one of the two thresholds is set to the higher value. The threshold 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 mere temperature change in the detection area, a mere temperature change other than the human body detection is performed. Therefore, it is possible to prevent the detection signal output due to the above from being determined as a human body detection signal, and it is possible to appropriately prevent an erroneous determination of the human body detection.

On the other hand, after a human body has entered the detection area and an 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 different. The threshold on the level side is determined as an infrared detection signal. With such a low output level threshold value, even if the movement of the human body is small, the operation can frequently output an infrared detection signal exceeding the low output level threshold value at short time intervals. Therefore, it is possible to prevent not only that the human body is determined to be absent, even though the human body is present in the detection area, but also to set the time for determining that the human body is absent due to the interruption of the human body detection signal. Even if is shortened, as long as the human body is present in the detection area and performs some operation, there is no possibility that the human body is determined to be absent. As a result, after the human body has actually left 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 type human body detector K according to the present invention.
FIG. 3 is a block diagram illustrating an example of a hardware configuration of the first embodiment. The infrared human body detector K shown in FIG. 1 includes an infrared detecting element 2 that receives infrared light via a condenser 1 such as a Fresnel lens, and an amplification unit that amplifies an infrared detection signal output from the infrared detecting element 2. 3. It has a bandpass filter circuit 4 for removing unnecessary frequency components from the detection signal amplified by the amplifier 3. In addition to the above, in the subsequent stage of the bandpass filter circuit 4, the comparison circuit 5, the expansion circuit 6, the output control unit 7, and the threshold setting circuits 8a and 8 capable of setting two thresholds
b, and a threshold selection processing unit 9 and the like.

As an example of the infrared detecting element 2 among the above-mentioned sections, a type using a pyroelectric element whose voltage value changes by receiving infrared light is applied, and an output level corresponding to a change in the amount of received infrared light is applied. Is output. The infrared detecting element 2 and the condenser 1
It is preferable that a large number of detection beams are obtained at a narrow pitch in the detection area.

The threshold setting circuits 8a and 8b are used to set two types of thresholds H and L having different output levels. The threshold H on the high output level side uses the detection beam of the infrared detecting element 2 for the human body. Is slightly lower than the output level of the infrared detection signal output from the bandpass filter circuit 4 when the light is blocked, but higher than the output level of the detection signal output due to a rapid temperature change or the like in the detection area. The value applies. On the other hand, as the threshold value L on the low output level side, a value lower than the threshold value H on the high output level side is applied, but is output when the human body performs an appropriate operation in a state where it stays in the same place. A value slightly lower than the output level of the detection signal is applied. The threshold setting circuits 8a and 8b are configured such that desired specific values can be arbitrarily set as the two types of thresholds H and L, and preferably, the values can be appropriately increased or decreased.

The comparison circuit 5 includes the threshold setting circuits 8a and 8
b of the two types of thresholds,
And compares one of the threshold values switched and output with the output level of the infrared detection signal output from the bandpass filter circuit 4. If the result of the comparison by the comparison circuit 5 indicates that the infrared detection signal exceeds a predetermined threshold, the extension circuit 6 sets the detection signal to a predetermined time T.
This is for extending only the output. 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 lighting a lighting fixture as an example of a control target, while continuing from the extension circuit 6. When the reception of the output signal is interrupted, a relay signal for turning off the lighting equipment at that time is output. That is, the infrared human body detector K according to the present embodiment
Determines that the human body is present 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 time and the human body is absent. It is configured to determine that no longer exists.

The threshold value selection processing section 9 selects one of the two threshold value setting circuits 8a and 8b so that the appropriate threshold value H or L is input to the comparison circuit 5. That is, the threshold selection processing unit 9 selects the threshold H on the high output level side set in the one threshold setting circuit 8a in the normal setting state in which the human body is determined to be absent in the detection area. In such a state, when an infrared detection signal exceeding the threshold is output, the changeover switch 10 is operated so as to select the low output level threshold L set in the other threshold setting circuit 8b at that time. Switching control is performed. Further, in a state where the low output level threshold L set on the other threshold setting circuit 8b side is selected, when the continuous signal output from the stretching circuit 6 is interrupted, the original threshold setting circuit The switching control is performed so as to select the threshold value H on the high output level side set on the 8a side.

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

After the above setting, in an initial state when the human body is detected, one of the two threshold setting circuits 8a and 8b is selected and one of the two threshold setting circuits 8a and 8b is selected. High output level side is selected.
Therefore, even if, for example, a temperature change occurs in the detection area in a state where no person is present in the detection area, the detection signal output from the infrared detection element 2 due to the temperature change in FIG.
As shown in A of FIG. 7A, 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 the 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 shown in B of (a), an infrared detection signal exceeding the threshold value H on the high output level side is output. Accordingly, at that time, the signal output from the extension circuit 6 is started, and the output control section 7 outputs a relay signal for lighting the lighting fixture R as shown in FIG. The lighting fixture R is turned on.

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

On the other hand, when the human body exits the room in the above state, a detection signal having a high output level as shown at D in FIG. Is no longer continuously output. Then, the signal output from the stretching circuit 6 is D
Is interrupted when a certain extension time T has elapsed since the detection signal was output. As a result, a relay signal for turning off the lighting fixture R is output from the output control unit 7, and the lighting is appropriately turned off. In addition, the human body goes out of the room
High if the human body moves significantly indoors before leaving
An output level detection signal may be output.
Exceed the threshold on the L side regardless of the output level of the knowledge signal
Threshold level is on the L side if no
To the H side from the
Output signal of high output level
Also, the threshold level immediately switches from the L side to the H side.
There is nothing.

The extension time T in the extension circuit 6 is, as described above, the extension of the detection signal which is frequently detected at short intervals when a human body is present. A short time that does not interrupt the operation is sufficient. Therefore, if the extension time T is set to a short time, the time until the lighting fixture R is turned off after leaving the human body,
Similarly, it can be very short. After the signal output from the stretching circuit 6 has been interrupted after the human body has left, the threshold selection processing unit 9 again selects the threshold H on the high output level side and returns to the original initial state. Therefore, it is possible to prevent the detection signal of a low output level other than the human body detection from being erroneously determined as the human body detection.

In the above embodiment, when the signal output from the stretching circuit 6 is interrupted, it is determined that the human body is absent (corresponding to claim 2). For example, the timer circuit is reset every time a detection signal exceeding the threshold value is output, and the subsequent time measurement is performed. When the next detection signal is not output while a predetermined fixed time is measured by the timer circuit or the like. May be determined to be a human body.
Corresponding to). Further, in the above embodiment, the case where the threshold value is set by the threshold value setting circuits 8a and 8b and the hardware value is set so as to input the set value to the comparison circuit 5 has been described. It is not limited to. For example,
The setting of the two types of thresholds and the comparison of the output levels may be performed by a software program using a signal processing unit using a CPU or the like.

[0023]

As can be understood from the above description, according to the infrared type human body detector according to the present invention, the movement of a small human body is detected by using the threshold value on the low output level side among the two types of threshold values. Since it is possible to make a determination, it is possible to reduce the set time for determining that the human body is absent by interrupting the output of the detection signal, and determine that the human body is absent after the human body exits the detection area. As a result, it is possible to obtain a special effect that it is possible to eliminate as much as possible, for example, a lighting fixture that remains on for a long time after leaving the human body. Moreover, according to the present invention, in a state other than the time of detecting a human body, the threshold value on the high output level side is compared with the detection signal of infrared rays. There is also an advantage that the possibility of erroneously determining a low output level detection signal as a human body detection can be eliminated, and the reliability of the human body detection can be improved.

[Brief description of the 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 use state of the infrared human body detector according to the present invention.

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

[Explanation of Signs] 1 Condenser 2 Infrared detector 5 Comparison circuit 6 Expansion circuit 7 Output controller 8a, 8b Threshold setting circuit 9 Threshold selection processor K Infrared human body detector R Lighting equipment

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01P 13/00 G01V 9/04

Claims (3)

(57) [Claims] An infrared detecting element for receiving infrared light from a detection area and outputting a detection signal having an output level corresponding to a change in the amount of received light; Comparing means for determining that a human body is present when a detection signal having an output level exceeding a threshold is output, and detecting the detection signal having an output level exceeding the threshold within a predetermined time after the output of the detection signal. Is not output continuously, it is determined that the human body is absent, an infrared human body detector configured to output a predetermined signal to the outside, and a threshold of an output level to be compared with an infrared detection signal In the normal setting state where at least two types are set and the human body is determined 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. The threshold value on the low output level side is compared with the infrared detection signal after the detection signal of the infrared ray exceeding the threshold value on the high output level side is output. Infrared human body detector. 2. The method according to claim 1, further comprising a stretching circuit for extending an infrared detection signal having an output level exceeding a threshold for a predetermined time and outputting the signal, and when the signal output from the stretching circuit is continued. An infrared human body detector configured to determine that a human body is present and to determine that the human body is absent when signal output is interrupted. 3. A timer circuit according to claim 1, wherein the timer circuit is reset every time a detection signal of an output level exceeding a predetermined threshold is output from the infrared detection element, and the measurement time reaches a predetermined fixed time. An infrared human body detector configured to judge that a human body does not exist at the time of the detection.