JP2691910B2 - Human body detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an infrared light receiving type that detects a difference between the amount of infrared radiation radiated from a human body and the amount of infrared radiation radiated from a background such as a floor surface by moving a human body. The present invention relates to a human body detection device.

[Conventional technology]

The infrared ray receiving type human body detection device is a device that detects a human body by detecting the temperature difference between the human body and the background as a difference in the amount of infrared energy using an infrared detection element such as a pyroelectric element. At the same time, there is a demand for improved reliability. Possible causes of the malfunction of the infrared ray detection type human body detection device include background temperature change and internal noise in the detection area, and the influence of disturbance light with large energy such as headlights and sunlight. Conventionally, various proposals have been made in order to eliminate such a problem.

As one of them, there has been proposed a human body detecting device of a system which obtains two sets of differential outputs by using four infrared detecting elements (Japanese Patent Laid-Open Nos. 58-213396 and 59-94094). ). An example of the detection operation of this human body detecting device is shown in FIGS. 6 and 7. 4 infrared detectors A ⁺ on the object surface,
Four detection areas I to IV are set by A ⁻ , B ⁺ , and B ⁻ , and each differential output v _A (between the infrared detection elements A ⁺ and A ⁻ is set by the detection areas I and IV and the detection areas II and III. output), v _B (infrared detection element B ^+, B ^- output between) are obtained. In the case of FIG. 6 (a), the human body M moves from the detection areas I and III to the detection areas II and I.
Moving to V, both differential outputs v _A and v _B as shown in FIG. 7 (a) are obtained. In the case of FIG. 6B, the human body M moves from the detection regions I and II to the detection regions III and IV, and both the differential outputs v _A and v _B as shown in FIG. 7B are obtained. . However, in the case of FIG. 6 (c), as shown in FIG. 7 (c), the differential output v _A can be obtained, but the differential output v _B is in the detection region.
Since the human body M crosses II and III at the same time, the output is canceled and the differential output v _B is not output. Therefore, in order to reliably detect the movement of the human body M, it is necessary to output the human body detection output when any one of the differential outputs v _A and v _B produces an output.

However, in this case, there is a problem that one of the differential outputs v _A and v _B produces an output due to a temperature change or the like occurring in one detection region, which causes a malfunction.

Therefore, the present inventors have proposed a highly reliable human body detection device by using a plurality of infrared detection elements and comparing the outputs of the infrared elements (Japanese Patent Application No. 62-2420).
No. 90). FIG. 8 shows a block diagram of the entire configuration of the human body detecting device. Infrared rays from the detection area are collected by the optical system 1, and the collected infrared rays are detected by a plurality of infrared detecting elements A to
The infrared detecting element section 2 made of D is used to receive light, each output is independently amplified by the amplifying section 3, and then the signal processing section 4 is used.
The signal processing is performed by the determination unit 5, the determination unit 5 detects the peak value and the output time, these are compared with each other to determine the presence or absence of a human body, and the determination unit 5 outputs the determination result.

The detection operation by this human body detection device is shown in FIG. 3 and FIG.
A description will be given based on the drawings. First, attention is paid to each output of the infrared detection elements A to D. Each of the detection areas A'to D'corresponding to the infrared detecting elements A to D is narrowed down to an area sufficiently smaller than the human body M. When the human body M moves, it is considered that the human body M passes through the entire detection areas A'to D'regardless of the moving direction, so that the peak values at the respective outputs of the infrared detection elements A to D are substantially the same. . Actually, the peak value at each output varies to some extent due to the temperature distribution on the human body surface and the like. Further, the peak value V _A ~V _D is also affected by the ambient temperature. Therefore, relative comparison may be performed for each peak value V _{A to} V _D. That is, the peak value V _{A to} V _D
The maximum value when the V _max of the threshold based on the V _max
VTA is set, and it is determined that the human body exists when all other peak values exceed the threshold _VTA . If the ratio of V _max to the threshold value V _TA is S, that is, the threshold value V _TA / V _max = S, then another peak value Vi
For (i = A, B, C, D), the condition for determining the presence of the human body may satisfy the following equation.

Vi / V _max S ... Next, pay attention to the output times t _{A to} t _D. When the human body moves in the detection areas A ′ to D ′, it does not enter all the detection areas A ′ to D ′ at the same time regardless of the moving direction.
That is, at the output times t _{A to} t D of the infrared detection elements A to _D ,
There is a time difference. This time difference can be limited to a certain range by considering the size of the detection areas A ′ to D ′ and the moving speed of the human body. Assuming that the time difference between the output times t _{A to} t _D is Δt, the condition for the existence of the human body is to satisfy the following equation.

T ₁ <Δt <T ₂ ... However, T ₁ and T ₂ are the upper and lower limits of the time difference, respectively.
In the example of FIG. 4, in any of the cases of (a), (b), and (c), the time difference is obtained as Δt = t _D −t _A , and it is determined whether this Δt satisfies the expression. Good.

By detecting the presence or absence of the human body based on the above judgment conditions, it is possible to prevent malfunctions due to general temperature changes, ambient light such as sunlight, or local changes and the effects of internal noise, etc. It becomes a detection device.

[Problems to be solved by the invention]

However, in such a human body detection apparatus, the peak value and the output time from each infrared detection element A to D are captured one by one, and the determination unit 5 compares them with each other to determine the human body. Was being judged. Therefore,
After outputting the determination result, the peak value and the output time data were cleared.

For example, as shown in FIG. 5, as the output of the infrared detection element A, the peak value V _A ′ due to noise and the output time t _A ′ are output before the output having the peak value V _A due to the human body and the output time t _A. In the case where there is an output that is included, the determination unit 5 uses the data of the peak value V _A ′ due to noise and the output time t _A ′ as the output of the infrared detection element A, and uses the data of the other infrared detection elements B to D. At the same time, the presence or absence of a human body is determined based on the mutual relationship between them. Therefore, in this case, it is determined that there is no human body, for example, based on the determination condition regarding the output time. Then, when this determination result is output, these data are once cleared. The data of the peak value V _A by the human body from the infrared detection element A and the output time t _A will be used in the next determination, but at this time, the data of the other infrared detection elements B to D are cleared. Therefore, there is a problem that it is judged that there is no human body, and eventually it will be lost.

The present invention has been made in view of the above points, and an object thereof is a human body detection device capable of reliably detecting the presence or absence of a human body even when output due to noise or the like occurs. To provide.

[Means for solving the problem]

The human body detection device of the present invention includes an optical system that collects infrared rays from a detection region, a plurality of infrared detection elements that receive the infrared rays that are collected by the optical system, and outputs of the plurality of infrared detection elements. Each of the infrared detecting element processed by the signal processing section, and a signal processing section for processing each output of the infrared detecting element amplified by the amplifying section into a signal suitable for human body detection The output time of the rising edge of the output is detected, the time difference of the output time of each infrared detection element is within a predetermined range, and the peak value of each output of each infrared detection element is the maximum among the peak values. A human body detection device comprising: a determination unit that determines that a human body is present when the ratio is equal to or greater than a predetermined ratio with respect to a value; and an output unit that outputs a determination result of the determination unit. Within a predetermined period of the device A storage unit that stores the peak value and the output time, and the determination unit determines the presence or absence of a human body by using the peak value and the output time of each infrared detection element within a predetermined period stored in the storage unit. It is characterized by doing so.

[Action]

The human body detection device of the present invention has a storage unit that stores the peak value of each output and the output time of the rise of each output within a predetermined period of each infrared detection element, and in this storage unit, the predetermined period. The peak value of the output of each infrared detection element and the output time are stored in advance, and when the peak value of the output of any of the infrared detection elements is detected, for example, a predetermined time is traced back from that time, and stored in the storage section. The stored peak values and output times of other infrared detection elements are extracted, and in the determination unit, all peak values are at least a predetermined ratio with respect to the maximum value among the extracted peak values, and each output time is Since it is determined that the human body exists when the time difference of is within the predetermined range, even if there is an output due to noise near the output of the human body, the peak value of the output by the human body and the output time are not ignored. Ah .

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.
Although the present embodiment shows a case where the number of infrared detecting elements is four, the present invention can be applied to a case where a number of infrared detecting elements other than four is used.

Reference numeral 1 denotes an optical system which collects infrared rays from a detection area using a mirror or a lens. In the case of this embodiment, infrared rays are condensed from a plurality of detection regions using a multi-segment mirror or a multi-segment lens. Reference numeral 2 denotes an infrared detecting element unit, which includes four infrared detecting elements A to D each composed of four pyroelectric elements or the like.
On the focal plane. As the infrared detection elements A to D, pyroelectric elements that can operate at room temperature were used, but thermopiles may also be used. By arranging the infrared detecting elements A to D on the focal plane of the optical system 1, as shown in FIG. 3, a plurality of detection areas A'to D'through the optical system 1 on the object plane are on the focal plane. The infrared detecting elements A to D are formed in the same arrangement as that of the infrared detecting elements A to D. When the human body moves within the detection areas A'to D ', each infrared detecting element A to D produces an output as a change in temperature difference from the background. Reference numeral 3 denotes an amplifying unit for independently amplifying the output of each of the infrared detecting elements A to D. Reference numeral 4 denotes a signal processing unit which is provided with a bandpass filter and extracts only necessary frequency components from each output, and each output passing through the bandpass filter is sequentially A / D converted by using a multiplexer and an A / D converter. You.

5 is a decision unit detects the output time t _A ~t _D of the rise of the peak value V _A ~V _D and the output from the output of the infrared detection element A~D processed in the signal processing unit 4, these The presence or absence of a human body is determined by comparing them with each other.

An output unit 6 outputs the judgment result from the judgment unit 5.

Reference numeral 7 denotes a storage unit, which includes storage units 7A to 7D for storing the data of the infrared detection elements A to D, respectively. The storage units 7A to 7D store at least the peak value of the waveform and the output time that appear in at least a predetermined period among the outputs of the infrared detection elements A to D, respectively.

Here, the process of determining the presence / absence of a human body by the determination unit 6 using the storage unit 7 and the data stored in the storage unit 7 will be described with reference to the flowchart of FIG. The peak value V _k of each output of the infrared detection elements A to D that appears in a predetermined period and the rising time (that is, output time) t _{k of} each output are paired and stored in the storage unit 7K. Then, the output time pair t _{k is} traced back to the period of the time T _max used for the condition for determining the presence or absence of the human body, and the data (peak of another element) within the predetermined period {(t _k −T _max ) −t _k } The storage unit 7 stores the value V _k ′ and the output time t _k ′).
Extract from K '(K' = A to D, except K). Here, the data of the infrared detector K (peak value V _k , output time
By comparing t _k) and the data of the other infrared detecting device (peak value V _k 'and the output time t _k'), it determines the presence or absence of a human body. Among other elements, a predetermined period {(t _k −T _max ) 〜
If having there is a plurality of data in the t _k}, to perform the determination for all combinations. The predetermined period is set based on T _max , but is not limited to this.

The detection operation of this human body detecting device will be described with reference to FIG. First, attention is paid to each output of the infrared detection elements A to D. Each detection area A'corresponding to the infrared detecting elements A to D
D'is narrowed down to an area sufficiently smaller than the human body M.
When the human body M moves, it is considered that the human body M passes through the entire detection areas A ′ to D ′ regardless of the moving direction.
The peak value at each output of the infrared detecting elements A to D is substantially the same. Actually, the peak value at each output varies to some extent due to the temperature distribution on the human body surface and the like. Further, the peak value V _A ~V _D is also affected by the ambient temperature. Therefore, relative comparison may be performed for each peak value V _{A to} V _D. That is, it is determined as the maximum value of the peak value V _A ~V _D and V _max, the threshold value is set V _TA based on the V _max, the human body is present when the other peak value exceeds all thresholds V _TA . If the ratio of Vmax and the threshold value V _TA is S, that is, the threshold value V _TA / Vmax = S, the other peak values Vi (i = A, B,
For C, D), the condition for determining the existence of the human body may satisfy the following equation.

Vi / V _max > S ... Next, pay attention to the output times t _{A to} t _D. When the human body moves in the detection areas A ′ to D ′, it does not enter all the detection areas A ′ to D ′ at the same time regardless of the moving direction.
That is, at the output times t _{A to} t D of the infrared detection elements A to _D ,
There is a time difference. This time difference can be limited to a certain range by considering the size of the detection areas A ′ to D ′ and the moving speed of the human body. When the time difference between the output times t _{A and} t _D is Δt, the condition for the human body is to satisfy the following equation.

T ₁ <Δt <T ₂ ... However, T ₁ and T ₂ are the upper and lower limits of the time difference, respectively.
In the example of FIG. 3, in any of the cases of (a), (b), and (c), the time difference is obtained as Δt = t _D −t _A , and it is determined whether or not this Δt satisfies the formula. Good. Here, in the figure, the output time is set to the rising time of the waveform for convenience, but the time when the waveform exceeds the threshold value V _TB is actually used.

The presence of the human body is detected when both the above determination conditions are satisfied.

Here, the operations of the determination unit 6 and the storage unit 7 will be described in detail with reference to FIG. As shown in FIG. 5, from the infrared detecting element A, the data due to noise (output time
t _A ′, peak value V _A ′) and data by the human body (output time t _A , peak value V _A ) are obtained. From the infrared detection elements B to D, data by the human body (output time t _B , peak value V _A ) are obtained. _B ),
(Output time t _C , peak value V _C ), (Output time t _D , peak value
Consider the case where V _D ) is obtained.

First, data due to noise (output time t _A ′, peak value
V _A ′) is stored in the storage unit 7A. At this time, storage unit 7B ~ 7D
Since the data is not stored, it judges that there is no human body. Infrared detecting element B data (output time t _B , peak value V _B ), infrared detecting element C data (output time t _C ,
Also for the peak value V _C ), the data is stored in the storage unit 7B,
It is stored in 7C, but it is judged that there is no human body because there is an element without data. Next, when the data of the infrared detection element D (output time t _D , peak value V _D ) is stored in the storage unit 7D, it means that the data from each of the infrared detection elements A to D have been prepared for the time being. The data of the element A (output time t _A ′, peak value V _A ′) is within a predetermined period ((t _D −T _max ) −
Since it is not within t _D ), it is determined that there is no human body after all.
Next, when the data of the infrared detection element A (output time t _A , peak value V _A ) is stored in the storage unit 7A, the data of the infrared detection element A (output time t _A , peak value V _A ) is a predetermined value. Period ((t _A
-T _max ~ t _A ) Since the above-mentioned judgment conditions are satisfied by mutual comparison with the data of the other infrared detection elements B to D within -T _max ~ t _A ),
It is judged that there is a human body.

That is, in the case of the conventional example, when it was determined that there was no human body at the output time t _D , all the data of each infrared detection element was cleared, but in the case of the present example, the output time of the newest data is Since the data for a predetermined period is stored retroactively, and these data are used to determine the presence or absence of a human body, there will be no false alarms.

〔The invention's effect〕

As described above, according to the present invention, an optical system that collects infrared rays from the detection region, a plurality of infrared detection elements that receive the infrared rays that are collected by the optical system, and a plurality of infrared detection elements An amplification section for amplifying each output, a signal processing section for processing each output of the infrared detection element amplified by the amplification section into a signal suitable for human body detection, and an infrared detection element processed by the signal processing section The output time of the rising edge of each output is detected, the time difference of the output time of each infrared detection element is within a predetermined range, and the peak value of each output of each infrared detection element is within the peak value. A human body detection device comprising a determination unit that determines that a human body is present when the ratio is greater than or equal to a maximum value with respect to the maximum value of the determination unit, and an output unit that outputs the determination result of the determination unit, Within the specified period of the infrared detector In the determination unit, the presence / absence of a human body is determined by using the peak value and the output time of each infrared detection element within a predetermined period stored in the storage unit. By doing so, it is possible to provide a human body detection device capable of reliably detecting the presence or absence of a human body even when an output due to noise or the like occurs.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation of the above, and FIG. 3 is a schematic diagram showing a detection area for explaining the operation of the same. FIG. 4 is a waveform diagram according to the above, FIG. 5 is a waveform diagram showing an example for explaining the operation of the above, FIG. 6 is a schematic diagram showing a detection region for explaining the operation of the conventional example, FIG. 7 is a waveform diagram according to the above, and FIG. 8 is a block diagram showing another conventional example. 1 ... Optical system, 2 ... Infrared detection element A to D ... Infrared detection element 3 ... Amplification section, 4 ... Signal processing section 5 ... Judgment section, 6 ... Output section 7 ... Storage section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Kiribata 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP 61-149887 (JP, A) Japanese Patent Publication 7-86537 (JP, B2)

Claims (1)

(57) [Claims] 1. An optical system for condensing infrared rays from a detection area, a plurality of infrared detecting elements for receiving the infrared rays condensed by the optical system, and respective outputs of the plurality of infrared detecting elements are amplified. A signal processing unit that processes each output of the infrared detection element amplified by the amplification unit into a signal suitable for human body detection, and a rise of each output of the infrared detection element processed by the signal processing unit Detects the output time of
When the time difference of the output time of each infrared detection element is within a predetermined range, and the peak value of each output of each infrared detection element is a predetermined ratio or more with respect to the maximum value among the peak values. A human body detection device comprising a determination unit that determines that a human body exists, and an output unit that outputs the determination result of the determination unit, wherein the peak value and the peak value within a predetermined period of each of the infrared detection elements It has a storage unit that stores each output time, and the determination unit is configured to determine the presence or absence of a human body by using the peak value and the output time of each infrared detection element within a predetermined period stored in the storage unit. A human body detection device characterized by: