JPH1139574A - Combined sensor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly and quickly detect masking when masking is performed on a sensor part in the combined sensor system using an MW sensor and a PIR sensor. SOLUTION: This system is provided with a sensor part 1 having a 1st sensor 3 for transmitting a microwave towards a detection area, and for receiving a reflected wave from a human body to detect the human body, and a 2nd sensor 4 for detecting the human body by receiving infrared rays from the human body in a 2nd detection area overlapped with the said detection area. Further, a discrimination circuit 19 is provided for discriminating the presence/ absence of an invader and a masking action based on human body detecting signals (m) and (p) from two sensors 3 and 4. After a human body approach- detecting signal d2 is detected by the 1st sensor 3, and only when a human body approach-detecting signal d3 from the 2nd sensor 4 is not detected within a fixed time T2, an interference detecting signal a2 is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active sensor using electromagnetic waves having a frequency lower than that of visible light, for example, a microwave sensor (hereinafter referred to as "MW sensor") and a passive infrared sensor (hereinafter referred to as "MW sensor"). PIR sensor ”).

[0002]

2. Description of the Related Art An intruder detection system using the above-described combination sensor system transmits a microwave toward a detection area, receives a reflected wave from a human body, and detects an intruder by its Doppler effect. And a PIR sensor that receives an infrared ray from the human body in the detection area and detects an intruder based on a difference between the human body and the ambient temperature. The detection area of the MW sensor and the detection area of the PIR sensor are overlapped, and the detection counts of both are counted. By taking the AND of the numbers, the weak points of both sensors are complemented, and the reliability against false alarm factors is increased.

[0003] By the way, the intruder detection system enters during the daytime when the user is not alert, and an object that does not transmit infrared light, such as paper or plastic, is attached to the lens portion on the front surface of the sensor to increase the detection area of the PIR sensor. There is a case where the human body is not detected by masking, and then enters again while the user is alert and commits a crime. In this case, P
Although the detection function of the IR sensor is impaired, since the MW sensor penetrates these masking materials to some extent, the number of detections of the human body by the MW sensor within a predetermined time period is performed in order to detect the presence or absence of such obstruction. And a detection count number of the PIR sensor. When the detection count numbers of the two are extremely different, it is determined that an obstructive action such as masking has occurred, and an interference detection signal is output.

On the other hand, if a masking action is performed during the operation of the intruder detection system, the level of the detection signal is significantly increased due to the approach of the human body to the sensor. No. 833,450 discloses a second interference detection means for outputting an interference detection signal when the detection level of the MW sensor exceeds a predetermined approach detection level, separately from the interference detection means.

[0005]

In the former intruder detection system, whether or not masking has been performed is determined by an MW sensor and a PI.
Since the judgment is made by comparing the detection counts of the R sensor, when there is little traffic in the detection area, there is a possibility that it is erroneous that the judgment time is not extended, and the judgment takes a long time. Also, when the detection area of the MW sensor passes through a wall or a window and protrudes from the room, only the MW sensor detects an outdoor pedestrian or a car.
The difference between the detection counts of the IR sensors becomes large, and the determination may be erroneous.

On the other hand, in the latter intruder detection system, M
It is configured to output a disturbance detection signal when a human body approaches the W sensor. For example, even when a cleaning person approaches the sensor for cleaning, the disturbance detection signal is output, so that it is troublesome to respond. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to accurately determine whether or not masking has been performed in a short time, and to detect an interference detection signal simply by approaching a sensor. It is an object of the present invention to obtain a combined sensor system that does not output erroneously.

[0008]

In order to achieve the above object, a first aspect of the present invention is to transmit an electromagnetic wave having a frequency lower than that of visible light toward a detection area, receive a reflected wave from a human body, and form a human body. A sensor unit having a first sensor for detecting, and a second sensor for detecting a human body by receiving infrared rays from a human body in a second detection area overlapping with the detection area, further comprising the first sensor A first detection circuit for detecting the presence of a human body in the detection area when the first detection signal from the first sensor exceeds a first threshold value; A second detection circuit for detecting that a human body has approached the sensor section when a second threshold value higher than the first threshold value is exceeded, and a second detection signal from the second sensor being a third detection signal; When a threshold is exceeded, a human body exists in the detection area A third detection circuit for detecting the door, the third within a predetermined time after detection by said second detection circuit
And a discriminating circuit for discriminating that there has been a sabotage action and outputting a jamming detection signal when the detection is not performed by the detecting circuit.

According to this configuration, the second detection circuit outputs M
After the human body approach detection signal is detected by the W sensor, the interference detection signal is output only when the human body approach detection signal is not detected by the PIR sensor within a certain time, so that an accurate interference detection signal can be output in a short time. Can be.

[0010] In a second aspect of the present invention, a third circuit is provided instead of the determination circuit.
When the detection by the second detection circuit is performed within a predetermined time after the detection by the detection circuit, and the detection by the third detection circuit is not performed within a predetermined time after the detection, it is determined that the obstructive act has occurred. Output the interference detection signal
Is provided.

According to this configuration, it is confirmed that the human body detection signal is output by the PIR sensor before detecting the human body approach detection signal by the MW sensor, so that the MW sensor malfunctions due to noise from outside. And the reliability of detection of sabotage by an intruder is increased.

Further, in the preferred embodiments of the present invention, when the detection by the third detection circuit is performed within a predetermined time after the detection by the second detection circuit, the release circuit for releasing the interference detection signal is provided. Have.

According to this configuration, even when a human body approaches the sensor, no interference detection signal is output when no interference is performed.

[0014]

FIG. 1 shows a sensor section according to an embodiment of the present invention. FIG. 1A is a front view, and FIG.
FIG. 2 is a sectional view taken along line bb in FIG. The sensor unit 1 includes a MW sensor 3 and a PIR sensor 4 in a case 2.
Is mounted, a front surface of the case 2 is covered with a cover 5 that transmits microwaves, and a Fresnel lens 6 is formed on a front surface of the PIR sensor 4.

FIG. 2 shows an arrangement position of the sensor unit 1 in the room equipped with the intruder detection system, the MW sensor 3 and the PI.
FIG. 2 is a diagram showing the relationship with the detection area of the R sensor 4;
2A is a side view, and FIG. 2B is a plan view. In FIG. 2, the sensor unit 1 is installed above a wall surface 9 a facing the door 8 among the wall surfaces 9 forming the room 7.
The detection area 10 indicated by the dashed line by the W sensor 3
Is set. The detection area 12 indicated by a hatched area by the PIR sensor 4 is set so that the interior 7 is covered with a plurality of beams by the Fresnel lens 6, and the detection area 10 by the MW sensor 3
The detection area 12 of the PIR sensor 4 overlaps. A and B in the figure are areas where people entering and exiting the room 7 normally pass, and C is a area where a human body usually approaches, except for those who perform maintenance such as inspection and cleaning of the sensor unit 1. It is an area without.

FIG. 3 is a block diagram showing an intruder detection system according to one embodiment of the present invention. In this intruder detection system, a human body detection signal m detected by the MW sensor 3 is amplified by a first amplifier 13, and an amplified signal m2 obtained by amplifying the amplified signal m1 by a second amplifier 14 is supplied to a first detection circuit. 1
5 and the amplified signal m1 is input to a second detection circuit 16. On the other hand, the human body detection signal p of the PIR sensor 4 is amplified by a third amplifier (usually a two-stage amplifier) 17, and this amplified signal p 1 is input to a third detection circuit 18.

FIG. 4 shows the signal levels of the amplified signals m1, m2 and p1 and the first to third detection circuits 15,
It is a figure which shows the relationship with the 1st-3rd threshold value r1-r3 in 16 and 18. The amplified signals m2, m1, p1 are the first
When each of the thresholds r1 to r3 is exceeded, first to third detection signals d1 to d3 are output from the first to third detection circuits 15, 16, and 18 to the determination circuit 19. The determination circuit 19 includes a human body detection circuit 20, a timer 21, a disturbance detection circuit 22, and a release circuit 23.

Next, the operation of the intruder detection system in a normal intruder detection mode will be described. The first detection circuit 15 in FIG. 3 is a circuit for detecting the presence or absence of an intruder from the amplified signal m2. When a person is present in the normal detection areas A and B (see FIG. 2), since the level of the human body detection signal m from the MW sensor 3 is low, the first and second amplifiers 13 and 14 perform two-stage amplification to amplify. The level of the signal m2 is raised and input to the first detection circuit 15. This first detection circuit 15
As shown in FIG. 3A, when the level of the amplified signal m2 exceeds the first threshold value r1, the first detection signal d1 of FIG.

On the other hand, the third detection circuit 18 outputs the amplified signal p
4 is a circuit for detecting the presence or absence of an intruder. When the level of the amplified signal p1 exceeds a third threshold value r3, a third detection signal d3 is output to the discrimination circuit 19, as shown in FIG. I do. The human body detection circuit 20 of the discrimination circuit 19 outputs the first detection signal d1 and the third signal d3 input within a predetermined time.
Are calculated, and when the calculation result is within a predetermined numerical value determined based on the actually measured data, it is determined that there is an intruder, and an alarm signal a1 is output.

In this operation mode, the level of the amplified signal m1 is low and does not exceed the second threshold value r2 set at a high level by the second detection circuit 16, so that the second detection circuit 16 does not output the second detection signal d2.

Next, in the intruder detection system according to the embodiment, a detection operation in the case where a masking act of attaching a masking material such as a blinding tape to the cover 5 of the sensor unit 1 will be described. Figure 5 shows that the intruder
The position of the intruder from entering the room 7 to approaching the sensor unit 1, performing masking and then leaving the room 7,
FIG. 4 is a diagram illustrating a relationship between a human body detection signal m of a W sensor 3 and a level of a human body detection signal p of a PIR sensor 4.

As shown in FIG. 5A, the level of the human body detection signal m of the MW sensor 3 changes according to the distance from the MW sensor 3 to the intruder, and within the detection area close to the MW sensor 3. Will be the largest. For this reason, the level of the amplified signal m2 of the second amplifier 14 becomes too high, and the signal exceeds the dynamic range of the amplifier and saturates. Therefore, the amplification of the first amplifier 13 is supplied to the second detection circuit 16. Signal m
1 is input, and the approach of the human body is detected at the second threshold value r2 higher than the first threshold value r1. Since the microwave of the MW sensor 3 passes through the masking material, the levels of the signals m, m1, and m2 do not decrease so much even after the masking.

On the other hand, the level of the human body detection signal p of the PIR sensor 4 does not largely change according to the distance from the PIR sensor 4 to the intruder as shown in FIG. Becomes

FIG. 6 is a timing chart for explaining the masking detecting operation, and FIG. 7 is a flowchart of the determining operation in the determining circuit 19. Step 1 in FIG.
(Hereinafter abbreviated as “S1”), when the intruder detection system enters an operating state, the discriminating circuit 19 in FIG.
Monitors the input state of the second detection signal d2 in S2. S
In FIG. 2, as shown in FIG.
When the detection signal d2 is input and the signal is turned off at time t2, the timer 21 is started in S3, and the third
The input state of the detection signal d3 is monitored.

In S4, as shown in FIG.
A predetermined time T required for stabilizing the output of the PIR sensor 4 from time t2 when the input of the third detection signal d3 is turned off.
After the lapse of 1 and before the lapse of the time T2, when the third detection signal d3 shown in FIG. 6D is input, the process returns to S2.
Then, as shown in FIG. 6 (f), an interference detection signal a2 is output at the end time t4 of the time T2. S4 and S5 are executed by the interference detection circuit 22 of the determination circuit 19 in FIG. When the interference detection signal a2 is output, it is notified by turning on a warning light, an alarm, or the like. Therefore, a function recovery measure such as confirmation of presence / absence of masking and removal of masking is taken by an operator.

According to this embodiment, the time T 1 + T 2 has elapsed since the intruder who performed the masking was separated from the sensor unit 1.
When the time has elapsed, it can be determined whether or not the masking has been performed. Since the time T1 is the time required for the amplified signal p1 output from the PIR sensor 4 to attenuate and stabilize, several seconds to several tens of seconds are sufficient. Since the time T2 is sufficient in a short time, the presence or absence of masking can be accurately detected in a short time.

Next, the operation during the masking removal operation of this embodiment will be described. After time t5 in FIG.
FIG. 7B is a timing chart when the worker performs the masking removal operation, and S6 to S9 in FIG.

When the interference detection signal a2 is output at time t4, the release circuit 23 of the discrimination circuit 19 monitors the input state of the second detection signal d2 in S6. In S6, as shown in FIG. 6B, when the worker enters the room 7 and approaches the sensor unit 1, the second detection signal d2 is input at time t5. When the worker moves away from the sensor unit 1 and the second time t
When the second detection signal d2 is turned off in step 6, the timer 21 is started in step S7, and the input state of the third detection signal d3 is monitored in step S8. In S8, as shown in FIG. 6 (e), after a predetermined time T1 has elapsed since the time t6 when the input of the second detection signal d2 was turned off, and before the time T2 has elapsed, the third detection signal d3 is output. S6 if not entered
Returning to FIG. 6, when the masking material has been removed and the third detection signal d3 is input as shown in FIG.
As shown in (f), at S9, the output of the interference detection signal a2 is stopped at the end time t7 of the time T2, and the process returns to S2 to enter the intruder detection mode.

According to this embodiment, by performing the masking removal operation, the output of the interference detection signal a2 can be stopped to return to the intruder detection mode, and even if a person approaches the sensor, interference such as masking can be prevented. If no action is taken, no interference detection signal a2 is output.

Next, another embodiment of the present invention will be described. The hardware configuration of this embodiment is the same as that of the embodiment shown in FIG. FIG. 8 is a flowchart of the discriminating operation in the discriminating circuit of this embodiment. The flowchart is the same as that of the embodiment shown in FIG. 7 except that S10 is provided between S1 and S2. Detailed description is omitted, and only the operation of the different part will be described below.

That is, when the system operates in S1,
The discriminating circuit 19 monitors the input state of the third detection signal d3 in S10. The MW sensor 3 in FIG. 3 may erroneously output the human body detection signal m due to a radio wave from the outside or the approach of a car, and the amplified signal m1 may exceed the second threshold value r2. On the other hand, the PIR sensor 4 does not cause such a malfunction. Therefore, in S10, PI
When the third detection signal d3 from the R sensor 4 is not input to the discrimination circuit 19, there is no intruder in the room 7, so that the process does not proceed to S2.

In S2, after the second detection signal d2 is inputted within a predetermined time after the detection of the third detection signal d3, it is monitored whether or not the second detection signal d2 is turned off. . Therefore, when the third detection signal d3 from the PIR sensor 4 is not input to the discriminating circuit 19, the interference detection signal a2 is not output, so that the accuracy of the interference detection can be improved. Here, the predetermined time is:
An error report is taken into account in consideration of the difference in the generation timing between the second detection signal d2 from the MW sensor 3 and the third detection signal d3 from the PIR sensor 4 and the reliability of ANDing the detection of both signals d3 and d2. To avoid as much as possible.

[0033]

According to the first aspect of the invention, after the approach of the human body is detected by the first sensor, the interference detection signal is output only when the human body is not detected by the second sensor within a predetermined time. With the configuration, an effect that an accurate disturbance detection signal can be output in a short time can be obtained.

According to the second invention, the approach of the human body is detected by the second detection circuit within a predetermined time after the detection of the human body by the third detection circuit, and the detection by the third detection circuit is performed within a predetermined time after the detection. When the human body is not detected, it is determined that a sabotage action has occurred and a hindrance detection signal is output, so that the effect of further enhancing the reliability of the detection of the sabotage action by the intruder can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a sensor unit used in the present invention.

FIG. 2 is a diagram showing a location of the sensor unit in a room and detection areas of a MW sensor and a PIR sensor thereof;
(A) is a side view, (b) is a plan view.

FIG. 3 is a block circuit diagram showing an intruder detection system according to an embodiment of the present invention.

FIG. 4 is a signal waveform diagram showing the relationship between the level of each amplified signal of the human body detection signal of the MW sensor and the PIR sensor and each threshold value.

FIG. 5 is a signal waveform diagram showing a waveform and a level of a human body detection signal of a MW sensor and a PIR sensor according to a position of an intruder.

FIG. 6 is a signal waveform diagram illustrating a timing of a masking detection operation according to an embodiment of the present invention and an operation at the time of masking removal.

FIGS. 7A and 7B show processing in a determination circuit according to an embodiment of the present invention, wherein FIG.
(B) is a flowchart of the interference cancellation processing.

FIG. 8 is a flowchart illustrating a process in a determination circuit according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sensor part, 3 ... MW sensor, 4 ... PIR sensor, 6
... Fresnel lens, 10 ... Detection area of MW sensor, 1
2: detection area of PIR sensor, 13: first amplifier,
14: second amplifier, 15: first detection circuit, 16: second detection circuit, 17: third amplifier, 18: third detection circuit, 19: discrimination circuit, 20: human body detection circuit, 21 ... Timer, 22 ... Interference detection circuit, 23 ... Release circuit, m ... MW
Human body detection signal detected by the sensor, m1, m2 ... amplified signal, p ... human body detection signal detected by the PIR sensor, p1
... amplified signal, r1 ... first threshold, r2 ... second threshold, r3 ... third threshold, a1 ... alarm signal, a2 ... interference detection signal, d1 ... first detection signal, d2 ... second No. 2 detection signal, d3 ... third detection signal, T2 ... fixed time.

Claims (3)

[Claims] 1. A first sensor for transmitting an electromagnetic wave having a frequency lower than that of visible light toward a detection area and receiving a reflected wave from a human body to detect a human body, and a second detection overlapping the detection area. A sensor unit having a second sensor for detecting a human body by receiving infrared rays from a human body in the area, and detecting a human body when the first detection signal from the first sensor exceeds a first threshold value. A first detection circuit for detecting the presence of a human body in the sensor section when a first detection signal from the first sensor exceeds a second threshold value higher than the first threshold value. A second detection circuit for detecting that a human body has approached, and detecting that a human body is present in the detection area when a second detection signal from the second sensor exceeds a third threshold value. A third detection circuit, after detection by the second detection circuit When the detection by the third detection circuit has not been made within a predetermined time, the combination sensor system and a discrimination circuit for outputting a disturbance detection signal to determine that there is sabotage. 2. The method according to claim 1, wherein the detection is performed by the second detection circuit within a predetermined time after the detection by the third detection circuit, and the detection is performed within a predetermined time after the detection. A combination sensor system comprising a second discriminating circuit for discriminating that a sabotage has occurred and outputting a jamming detection signal when detection by the third detection circuit is not performed. 3. The canceling circuit according to claim 1, further comprising a canceling circuit for canceling the interference detection signal when the detection by the third detecting circuit is performed within a predetermined time after the detection by the second detecting circuit. Combined sensor system equipped.