JP3936971B2 - Combination sensor system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides an active sensor using an electromagnetic wave 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 “PIR sensor”). It is related with the provided combination sensor system.
[0002]
[Prior art]
An intruder detection system using the combination sensor system includes a MW sensor that transmits a microwave toward a detection area, receives a reflected wave from a human body, and detects an intruder by the Doppler effect; A PIR sensor that receives an infrared ray from the human body and detects an intruder from the difference between the human body and the ambient temperature, overlaps the detection area of the MW sensor and the detection area of the PIR sensor, and takes the AND of the detection count number of both This compensates for the weaknesses of both sensors and increases the reliability of false alarm factors.
[0003]
By the way, entering the day when the intruder detection system is unwarmed, and masking the detection area of the PIR sensor by attaching something that does not transmit infrared rays, such as paper or plastic, to the lens part on the front of the sensor Depending on the situation, the human body may not be detected, and the person may enter the alert again and commit a crime. In this case, although the detection function of the PIR sensor is hindered, the MW sensor penetrates these masking materials to some extent. Therefore, in order to detect the presence or absence of such a disturbing action, the human body by the MW sensor within a predetermined time is detected. The detection count number is compared with the detection count number of the PIR sensor, and when the detection count numbers of the two are extremely different, it is determined that there is an obstruction act such as masking, and an interference detection signal is output.
[0004]
On the other hand, if a masking action is performed during the operation of the intruder detection system, the human body approaches the sensor, and the level of the detection signal becomes extremely high. In addition to the above-described interference detection means, there is provided second interference detection means for outputting an interference detection signal when the detection level of the MW sensor exceeds a predetermined approach detection level.
[0005]
[Problems to be solved by the invention]
In the former intruder detection system, whether or not masking is performed is determined by comparing the detection counts of the MW sensor and the PIR sensor. Therefore, when the traffic in the detection area is small, the determination time must be lengthened. There is a risk of error, and it takes a long time to make a decision. In addition, when the detection area of the MW sensor passes through a wall or window and protrudes from the room, only the MW sensor detects an outdoor pedestrian, a car, etc., so the detection count number of the MW sensor and the PIR sensor Differences can become large and misjudgment.
[0006]
On the other hand, since the latter intruder detection system is configured to output a disturbance detection signal when a human body approaches the MW sensor, for example, even when a cleaner approaches the sensor for cleaning, the disturbance detection signal is output. Is output, so there is a problem that handling is troublesome.
[0007]
The present invention has been made for the purpose of solving the above-described problems, and can accurately determine whether or not masking has been performed in a short time, and a false detection signal can be erroneously output simply by approaching the sensor. The object is to obtain a combination sensor system that does not.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the first invention is a first sensor for detecting a human body by transmitting an electromagnetic wave having a frequency lower than that of visible light toward a detection area and receiving a reflected wave from the human body, A sensor unit having a second sensor for detecting a human body by receiving infrared rays from a human body in a second detection area overlapping the detection area, and a first detection signal from the first sensor is a first threshold value A first detection circuit for detecting the presence of a human body in the detection area when exceeding the second threshold, and a second threshold value in which a first detection signal from the first sensor is higher than the first threshold value A second detection circuit for detecting that a human body has approached the sensor unit when the value exceeds the second detection circuit, and a second detection signal from the second sensor within the detection area when the second detection signal exceeds a third threshold value. A third detection circuit for detecting the presence of a human body; When the detection of human presence by the third detection circuit within a predetermined time after the detection of the human body proximity to the sensor unit by the detection circuit has not been made, and outputs an interference detection signal to determine that there is a sabotage, the A discriminating circuit for discriminating that there is no disturbing action when the presence of the human body is detected by the third detection circuit within a predetermined time after detection of the approach of the human body to the sensor unit by the second detection circuit; It is.
[0009]
According to this configuration, after the human body approach detection signal by the first sensor such as the MW sensor is detected from the second detection circuit, the human body detection signal by the second sensor such as the PIR sensor is detected within a predetermined time. Since the interference detection signal is output only when it is not detected, an accurate interference detection signal can be output in a short time.
[0010]
In the second invention, instead of the discrimination circuit, detection by the second detection circuit is performed within a predetermined time after detection by the third detection circuit, and the third detection circuit is detected within a certain time after the detection. When the detection by is not performed, a second discrimination circuit is provided that discriminates that there is an interference action and outputs an interference detection signal.
[0011]
According to this configuration, since it is confirmed that the human body detection signal is output from the PIR sensor before the human body approach detection signal is detected by the MW sensor, it is affected by malfunction of the MW sensor due to noise from the outdoors. This increases the reliability of detection of sabotage by intruders.
[0012]
Furthermore, in a preferred embodiment of both the inventions, there is provided a release circuit for canceling the disturbance detection signal when detection by the third detection circuit is made within a predetermined time after detection by the second detection circuit. .
[0013]
According to this configuration, even when a human body approaches the sensor, the disturbance detection signal is not output when the disturbance action is not performed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a sensor unit according to an embodiment of the present invention. 1A is a front view, and FIG. 1B is a cross-sectional view taken along the line bb in FIG. 1A. In the sensor unit 1, a MW sensor 3 and a PIR sensor 4 are mounted in a case 2, the front surface of the case 2 is covered with a cover 5 that transmits microwaves, and a Fresnel lens 6 is formed on the front surface of the PIR sensor 4. ing.
[0015]
FIG. 2 is a diagram showing the relationship between the location of the sensor unit 1 in the room equipped with the intruder detection system and the detection areas of the MW sensor 3 and the PIR sensor 4, and FIG. 2 (a) is a side view. 2 (b) is a plan view.
In FIG. 2, the sensor unit 1 is installed on the upper surface of the wall surface 9 a facing the door 8 among the wall surfaces 9 forming the room 7, and the detection area 10 indicated by the alternate long and short dash line is set by the MW sensor 3. ing. Further, the detection area 12 indicated by the hatched range by the PIR sensor 4 is set so as to cover the room 7 with a plurality of beams by the Fresnel lens 6, and the detection area 10 by the MW sensor 3 and the PIR sensor 4 overlaps the detection area 12. In addition, A and B in the figure are areas where people who normally enter and exit the room 7 pass, and C is that the human body normally approaches except for those who perform maintenance such as inspection and cleaning of the sensor unit 1. There is no area.
[0016]
FIG. 3 is a block diagram showing an intruder detection system according to an embodiment of the present invention. In this intruder detection system, the human body detection signal m detected by the MW sensor 3 is amplified by the first amplifier 13, and the amplified signal m2 obtained by amplifying the amplified signal m1 by the second amplifier 14 is the first detection circuit. 15 and the amplified signal m 1 is input to the 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 the third detection circuit 18.
[0017]
FIG. 4 is a diagram showing the relationship between the signal levels of the amplified signals m1, m2 and p1 and the first to third threshold values r1 to r3 in the first to third detection circuits 15, 16, and 18. It is. When the amplified signals m2, m1, and p1 exceed the first to third threshold values r1 to r3, the first to third detection signals d1 to d1 to the first to third detection circuits 15, 16, and 18, respectively. d3 is output to the discrimination 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.
[0018]
Next, the operation of the intruder detection system in the normal intruder detection mode will be described. The first detection circuit 15 in FIG. 3 is a circuit that detects 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), the level of the human body detection signal m from the MW sensor 3 is low, so that the first and second amplifiers 13 and 14 amplify and amplify it in two stages. The level of the signal m2 is increased and input to the first detection circuit 15. As shown in FIG. 4A, the first detection circuit 15 sends the first detection signal d1 of FIG. 3 to the discrimination circuit 19 when the level of the amplified signal m2 exceeds the first threshold value r1. Output.
[0019]
On the other hand, the third detection circuit 18 detects the presence or absence of an intruder from the amplified signal p1, and when the level of the amplified signal p1 exceeds the third threshold value r3 as shown in FIG. 4B. The third detection signal d3 is output to the discrimination circuit 19. The human body detection circuit 20 of the discrimination circuit 19 calculates each of the first detection signal d1 and the third signal d3 input within a predetermined time, and the calculation result is a predetermined value determined based on the actual measurement data. If it is within the numerical value, it is determined that there is an intruder and an alarm signal a1 is output.
[0020]
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 in the second detection circuit 16, so that the second detection circuit 16 to the second detection circuit 16 No second detection signal d2 is output.
[0021]
Next, in the intruder detection system of this embodiment, a detection operation when there is a masking act of attaching a masking material such as a blindfold tape to the cover 5 of the sensor unit 1 will be described. FIG. 5 shows the position of the intruder until the intruder enters the room 7, approaches the sensor unit 1, performs masking and then moves out of the room 7, the human body detection signal m of the MW sensor 3, and the PIR sensor It is a figure which shows the relationship with the level of 4 human-body detection signals p.
[0022]
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 becomes the maximum in the detection area close to the MW sensor 3. . For this reason, the level of the amplified signal m2 of the second amplifier 14 becomes too high, and the signal is saturated beyond the dynamic range of the amplifier, so that the second detection circuit 16 receives the amplification of the first amplifier 13. The signal m1 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 masking.
[0023]
On the other hand, the level of the human body detection signal p of the PIR sensor 4 does not change greatly according to the distance from the PIR sensor 4 to the intruder as shown in FIG. 5B, and becomes zero after masking.
[0024]
FIG. 6 is a timing chart for explaining the masking detection operation, and FIG. 7 is a flowchart of the discrimination operation in the discrimination circuit 19. In step 1 of FIG. 7A (hereinafter abbreviated as “S1”), when the intruder detection system enters an operating state, the discrimination circuit 19 of FIG. 3 inputs the second detection signal d2 in S2. Monitor status. In S2, as shown in FIG. 6 (b), when the second detection signal d2 is input at time t1 and then turned off at time t2, the timer 21 is started at S3, and the third detection signal at S4. The input state of the detection signal d3 is monitored.
[0025]
In S4, as shown in FIG. 6E, after the elapse of a predetermined time T1 required for stabilizing the output of the PIR sensor 4 from the time t2 when the input of the third detection signal d3 is turned off, the time T2 has not elapsed. When the third detection signal d3 shown in FIG. 6 (d) is input, the process returns to S2, and when it is not input, it is determined that there is a masking action, and in S5, as shown in FIG. 6 (f). The disturbance detection signal a2 is output at the end time t4 of time T2. S4 and S5 are executed by the disturbance detection circuit 22 of the determination circuit 19 of FIG. When this disturbance detection signal a2 is output, it is notified by the lighting of an alarm lamp, an alarm, etc., so that a function recovery measure such as confirmation of the presence or absence of masking and removal of masking is taken by an operator.
[0026]
According to this embodiment, when the time T1 + T2 has passed since the intruder who performed the masking has left the sensor unit 1, it can be determined whether or not the masking has been performed. The time T1 is the amplified signal of the output of the PIR sensor 4. Since the time required for p1 to decay and stabilize is sufficient, a few seconds to a few tens of seconds are sufficient, and the time T2 is also short. Therefore, the presence or absence of masking can be accurately detected in a short time.
[0027]
Next, the operation at the time of the masking removal work of this embodiment will be described. After time t5 in FIG. 6 (f), the timing chart when the worker performs the masking removal work, and S6 to S9 in FIG. 7 (b) are the flowcharts.
[0028]
When the disturbance detection signal a2 is output at time t4, the release circuit 23 of the determination 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 inputted at time t5. When the worker leaves the sensor unit 1 and the second detection signal d2 is turned off at the second time t6, the timer 21 is started in S7, and the input state of the third detection signal d3 is monitored in S8. . In S8, as shown in FIG. 6 (e), after the elapse of a predetermined time T1 from the time t6 when the input of the second detection signal d2 is turned off, the third detection signal d3 is received before the time T2 elapses. If it is not input, the process returns to S6. If the masking material is removed and the third detection signal d3 is input as shown in FIG. 6D, S9 is input as shown in FIG. The output of the disturbance detection signal a2 is stopped at the end time t7 of time T2, and the process returns to S2 to enter the intruder detection mode.
[0029]
According to this embodiment, the masking removal operation can stop the output of the interference detection signal a2 and return to the intruder detection mode, and even if a person approaches the sensor, there is no interference action such as masking. Otherwise, the disturbance detection signal a2 is not output.
[0030]
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 determination operation in the determination circuit of this embodiment. The flowchart shown in FIG. 7 of the embodiment is the same as that of FIG. 7 except that S10 is provided between S1 and S2. Detailed description will be omitted, and only the operation of different parts will be described below.
[0031]
That is, when the system operates in S1, the discrimination circuit 19 monitors the input state of the third detection signal d3 in S10. The MW sensor 3 of FIG. 3 may erroneously output the human body detection signal m due to radio waves from the outside or the approach of a car, etc., 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, when the third detection signal d3 from the PIR sensor 4 is not input to the discrimination circuit 19, it is assumed that there is no intruder into the room 7 and the process does not proceed to S2.
[0032]
In S2, after the second detection signal d2 is input 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 discrimination circuit 19, the interference detection signal a2 is not output, so that the interference detection accuracy can be improved. Here, for the predetermined time, a deviation of the generation timing of the second detection signal d2 from the MW sensor 3 and the third detection signal d3 from the PIR sensor 4 and the AND of the detection of both signals d3 and d2 are taken. Considering the reliability of the system, determine to avoid false alarms as much as possible.
[0033]
【The invention's effect】
According to the first aspect of the present invention, after the human body approach is detected by the first sensor, the disturbance detection signal is output only when the human body is not detected by the second sensor within a predetermined time. An effect of being able to output an accurate disturbance detection signal in time can be obtained.
[0034]
According to the second invention, the approach of the human body is detected by the second detection circuit within a predetermined time after the human body detection by the third detection circuit, and the human body detection by the third detection circuit is performed within a certain time after the detection. If it is not done, it is determined that there is an obstruction act and the obstruction detection signal is output, so that the effect of further improving the reliability of the detection of the obstruction act 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.
FIGS. 2A and 2B are views showing a position of the sensor unit in the room and detection areas of the MW sensor and the PIR sensor, where FIG. 2A is a side view and FIG. 2B 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 modes of waveforms and levels of human body detection signals of the MW sensor and PIR sensor according to the position of an intruder.
FIG. 6 is a signal waveform diagram showing a timing of a masking detection operation and an operation at the time of masking removal according to an embodiment of the present invention.
FIGS. 7A and 7B show processing in a discrimination circuit according to an embodiment of the present invention, in which FIG. 7A is a flowchart of interference detection processing, and FIG. 7B is a flowchart of interference cancellation processing;
FIG. 8 is a flowchart showing processing 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,
DESCRIPTION OF SYMBOLS 10 ... Detection area of MW sensor, 12 ... Detection area of PIR sensor, 13 ... 1st amplifier, 14 ... 2nd amplifier, 15 ... 1st detection circuit, 16 ... 2nd detection circuit, 17 ... 3rd 18 ... third detection circuit, 19 ... discriminating circuit, 20 ... human body detection circuit, 21 ... timer, 22 ... disturbance detection circuit, 23 ... release circuit, m ... human body detection signal detected by MW sensor, m1 , M2 ... amplified signal, p ... human body detection signal detected by PIR sensor, p1 ... amplified signal, r1 ... first threshold value, r2 ... second threshold value, r3 ... third threshold value, a1 ... alarm Signal, a2 ... disturbance detection signal, d1 ... first detection signal, d2 ... second detection signal, d3 ... third detection signal, T2 ... fixed time.

Claims (3)

From a first sensor that transmits an electromagnetic wave having a frequency lower than that of visible light toward a detection area, receives a reflected wave from the human body and detects the human body, and a human body in a second detection area that overlaps the detection area A sensor unit having a second sensor for detecting a human body by receiving infrared rays of
A first detection circuit for detecting the presence of a human body in a detection area when a first detection signal from the first sensor exceeds a first threshold;
A second detection circuit that detects that a human body has approached the sensor unit when a first detection signal from the first sensor exceeds a second threshold value that is higher than the first threshold value;
A third detection circuit for detecting the presence of a human body in the detection area when a second detection signal from the second sensor exceeds a third threshold;
When the presence of the human body is not detected by the third detection circuit within a predetermined time after the detection of the approach of the human body to the sensor unit by the second detection circuit, it is determined that there is an interference action and the interference detection signal is generated. A discriminating circuit that outputs and discriminates that there is no disturbing action when the presence of the human body is detected by the third detection circuit within a predetermined time after the detection of the approach of the human body to the sensor unit by the second detection circuit; Sensor system with   In Claim 1, instead of the discrimination circuit, the second detection circuit detects the approach of the human body to the sensor unit within a predetermined time after the detection of the human body presence, and after the detection, A combination sensor system including a second discrimination circuit that discriminates that there has been a disturbing action and outputs a disturbance detection signal when the presence of the human body is not detected by the third detection circuit within a predetermined time.   3. The interference detection signal according to claim 1 or 2, wherein when the presence of a human body is detected by a third detection circuit within a predetermined time after detection of human approach to the sensor unit by the second detection circuit, A combination sensor system having a release circuit for releasing.

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