JP6755451B2 - Distance measurement type intrusion detection sensor using a reflective member and its optical axis adjustment method - Google Patents

Description

The present invention relates to a distance measuring type intrusion detection sensor composed of a distance measuring sensor unit having a light emitting unit and a light receiving unit, and a reflective member having retroreflective properties.

Conventionally, there is a photoelectric sensor composed of a sensor unit having a light emitting unit and a light receiving unit and a reflective member having retroreflective properties. (See, for example, Patent Document 1 and Patent Document 2) Since it is not necessary to supply power to the reflective member side, it is often used in places where there are restrictions on wiring work.

A sensor unit and a reflective member having retroreflective properties are installed facing each other across a warning area, and a human being (intruder) blocks light emitted from a light projecting unit in the warning area to receive light. This state is detected by the unit and an intruder detection signal is output.
In order to use it in a good condition, it is necessary to obtain a sufficient amount of light received, and the optical axis is adjusted so that the optical axes between the light projecting part and the reflecting member and between the reflecting member and the light receiving part match. There is a need. If the amount of light received is low, malfunctions will occur due to sunlight, car headlights, and shaking of trees.

In addition, the presence or absence of an intruder in the caution area is determined by measuring the distance to the reflecting object by receiving the reflected light of the light projected from the light projecting unit with the light receiving element, and the intruder detection signal. There is also a ranging type intrusion detection sensor that outputs. (See, for example, Patent Document 3)

Japanese Unexamined Patent Publication No. 2000-321368 Japanese Unexamined Patent Publication No. 2004-226282 Japanese Unexamined Patent Publication No. 2013-228834

However, in a photoelectric sensor using a conventional reflective member, if the distance between the sensor unit and the reflective member having retroreflective property, that is, the warning distance is set to a long distance, a sufficient amount of light is received by the light receiving portion. It was necessary to increase the projection power of the projection section. However, if an intruder passes near the sensor unit even though it is in the caution area, the light projected from the light emitting part will be reflected by the intruder and enter the light receiving part. As a result, the detection signal is not output (missing report). Therefore, there was only a photoelectric sensor using a reflective member having a warning distance of about 10 m.

Furthermore, when adjusting the optical axis, the amount of light received is monitored and adjusted so that it becomes larger. However, if there is a reflecting object in a direction different from that of the reflecting member, the amount of light received increases even if the sensor unit is pointed in the direction of the reflecting object. Therefore, there was a problem that the assumed caution area could not be realized.

Further, in the conventional distance measuring type intrusion detection sensor, as shown in FIG. 8, the light projected from the distance measuring type intrusion detection sensor 101 spreads, so that the caution area 102 also spreads to an angle θ. Sometimes I couldn't be alert in a narrow range.

Therefore, according to the present invention, in the intrusion detection sensor using the reflective member, the optical axis can be adjusted accurately, the long-distance alert can be performed as compared with the photoelectric sensor using the conventional reflective member, no false alarm occurs, and a narrow alert area can be created. The challenge is to be able to achieve it.

In order to solve the above problems, the distance measuring type intrusion detection sensor of the present invention is a distance measuring type intrusion composed of a distance measuring sensor unit including a light emitting unit and a light receiving unit and a reflective member having retroreflective property. In the detection sensor, the distance measuring sensor unit includes a distance measuring unit, a light receiving amount measuring unit, a distance storage unit, and a light receiving amount storage unit, and measures the distance from the sensor unit to the reflecting member measured by the distance measuring unit. The distance storage unit stores the light reception amount measured by the light reception amount measurement unit at that time, and the light reception amount storage unit stores the light reception amount, and the distance measured by the distance measurement unit is a threshold value 1 preset from the stored distance. The detection signal is output when the light receiving amount changes beyond the above, or when the light receiving amount measured by the light receiving amount measuring unit changes beyond the preset threshold value 2 from the stored light receiving amount.

According to this configuration, intrusion detection is determined not only by the change in the amount of received light but also by the change in the distance, so that the detection signal can be output even if the intruder passes near the distance measurement sensor unit, resulting in loss. There is no news. Further, as shown in FIG. 7, the caution zone 3 is formed at an angle δ between the distance measuring sensor unit 1 and the reflecting member 2, and can be made narrower than the angle θ when the reflecting member 2 is not used. This angle δ can be changed by changing the size of the reflecting member to a different size, and the size of the detection target can be changed according to the change in the amount of received light.

When the conventional ranging type intrusion detection sensor 101 and the reflective member 103 are simply combined and installed near the wall as shown in FIG. 9, even if the intruder 105 enters the caution area 104, the light reflected by the wall surface 106 or the like wraps around. Then, since the optical path 107 returns to the distance measuring type intrusion detection sensor 101, if the distance of the optical path 107 does not exceed the threshold value 1 from the distance between the distance measuring type intrusion detection sensor 101 and the reflective member 103, a false report occurs. It ends up. However, since the distance measuring sensor using the reflective member of the present invention determines intrusion detection not only by the change in the distance but also by the change in the amount of received light, it is possible to prevent the misreporting due to the wraparound of the light.

Further, it is preferable that the threshold value 2 is a value obtained by multiplying the average value of the light receiving amount for the predetermined time a preset by α (where α is a constant), and is updated every predetermined time a.

By setting the threshold value 2 in this way, a detection signal is output for gradual fluctuations in the amount of light received due to weather conditions such as rain and fog, and changes in the environment such as dirt on the cover and windows of the ranging sensor unit. It can be prevented and malfunction due to changes in the environment can be prevented.

Further, during the detection signal output, the average value of the received light amount is not used, the update work of the threshold value 2 is stopped, and the average value of the received light amount calculated from the received amount after returning to the non-detection state is used. It is preferable to use it and restart the update work of the threshold value 2.

If an intruder stays in the caution area for a long time, the amount of received light is low for a long time, and if the threshold value 2 is updated at this time, the amount of received light is small, but the detection signal is not output. It will be in a state of information. However, by stopping and restarting the update work of the threshold value 2 as in the present invention, it is possible to prevent a false report when an intruder exists in the caution area for a long time.

Further, in updating the threshold value 2, it is preferable to set a maximum value for the amount of change.
When an intruder slowly invades the caution area, the amount of change in the amount of light received up to a predetermined time a may reach the threshold value of 2. If this happens continuously, even if the total change in the amount of received light is large, a false alarm state in which the detection signal is not output will occur.
In order to detect when an intruder slowly invades the caution area, the predetermined time a should be set longer, but if it is set longer, the sampling interval must be set longer when calculating the average value of the received light amount. It is not desirable because it increases the amount.
By setting the maximum value for the amount of change in the update of the threshold value 2 as in the present invention, it is possible to prevent a false report when an intruder slowly enters the caution area and to reduce the amount of data regarding the amount of received light. it can.

Further, a distance output unit for outputting the measured distance and a light receiving amount output unit for outputting the received light amount are provided, and the output range of the received light amount output unit is set by the distance measured by the distance measuring unit, and the distance output is performed. The output values of the unit and the light receiving amount output unit are output by an independent output unit or an output unit that can be switched and used.
In the optical axis adjustment, the distance between the distance measuring sensor unit and the reflecting member is measured and grasped in advance so that the output value of the distance output unit becomes the distance between the distance measuring sensor unit and the reflecting member. After roughly adjusting the direction of the sensor unit, the light receiving amount is adjusted according to the output value of the light receiving amount output unit, and the direction of the sensor unit is finely adjusted.

The light receiving amount output unit used for adjusting the optical axis of the conventional photoelectric sensor using a reflective member or the opposed type photoelectric sensor has the same output range even at different warning distances. It is clear that the longer the warning distance, the smaller the amount of light received, and the amount of light received differs between when adjusting the optical axis over a long distance and when adjusting the optical axis over a short distance, so long distances In the case, the direction of the sensor can be adjusted with a fine angle, but in the case of a short distance, it cannot be adjusted with a fine angle.

In the optical axis adjustment method of the present invention, since the output range of the light receiving amount output unit is set according to the warning distance, detailed and accurate optical axis adjustment is possible at any warning distance, malfunctions can be reduced, and stable detection performance can be achieved. Can be demonstrated.

According to the present invention, in a distance measuring type intrusion detection sensor using a reflective member, the optical axis can be adjusted accurately, long-distance warning can be performed as compared with a photoelectric sensor using a conventional reflective member, no misreporting occurs, and A narrow caution area can be realized.

It is a figure which showed the operation state of the distance measuring type intrusion detection sensor of this invention. It is a block diagram which shows one Embodiment of the ranging sensor unit of this invention. It is a figure which showed an example of the relationship between the fluctuation of the light receiving amount and the threshold value 2 in one Embodiment of this invention. It is a figure which showed an example of the relationship between the light receiving amount, the threshold value 2, and the detection state when an intruder exists in a caution area for a long time in one Embodiment of this invention. It is a figure which showed an example of the relationship between the light receiving amount, the threshold value 2, and the detection state when an intruder slowly invades into a caution area in one Embodiment of this invention. It is a graph which showed an example of the relationship between the distance measured by the distance measuring part and the output voltage of a distance output part in one Embodiment of this invention. It is a figure which showed the caution area of the distance measuring type intrusion detection sensor of this invention. It is a figure which showed the caution area of the conventional ranging type intrusion detection sensor. It is a figure which shows the case where the conventional distance measuring type intrusion detection sensor and the reflection member are combined and installed near the wall.

FIG. 1 shows an operating state of the ranging type intrusion detection sensor of the present invention.
As shown in FIG. 1, the distance measuring sensor unit 1 and the reflective member 2 having retroreflective properties are installed and operated so as to face each other with a warning area in between.

FIG. 2 is a block diagram showing an embodiment of the ranging sensor unit of the present invention.
The distance measuring sensor unit 1 is composed of a distance measuring unit 10, a CPU unit 20, and an output unit 30, and the distance measuring unit 10 includes a light emitting unit 11 and a light receiving unit 12, and is controlled by the light emitting and receiving control unit 14. In the light projecting unit 11 and the light receiving unit 12, the reflected light of the light projected from the light projecting unit 11 is received by the light receiving unit 12, and the distance measuring unit 15 receives the reflected light based on the time required from the light projection to the light receiving. Is measuring the distance to.
Further, the light receiving amount received by the light receiving unit 12 is measured by the light receiving amount measuring unit 13.

The distance measuring sensor unit 1 is installed so that the light projected from the light projecting unit 11 is reflected by the reflecting member 2 and received by the light receiving unit 12.
The distance d from the distance measuring sensor unit 1 to the reflecting member 2 measured by the distance measuring unit 15 is stored in the distance storage unit 22 in the CPU unit 20, and the light receiving amount R measured by the light receiving amount measuring unit 13 at that time is stored in the CPU unit. It is stored in the light receiving amount storage unit 21 in 20.

When the distance measured by the distance measuring unit 15 changes from the value of the distance storage unit 22 beyond the preset threshold value 1, or the light receiving amount R measured by the light receiving amount measuring unit 13 is calculated from the value of the light receiving amount storage unit 21. When the change exceeds the preset threshold value 2, the signal control / processing unit 23 determines that there is an intruder, and the detection signal output unit 31 outputs a detection signal.

By outputting a detection signal due to a change in distance or a change in the amount of light received, only monitoring of the change in the amount of light received and the misreporting caused by the wraparound of light due to a wall, etc. that occurs when monitoring only the distance as shown in Fig. 8 It is possible to prevent false alarms of light-shielding objects near the distance measuring sensor unit that occur in.

The amount of light received fluctuates due to weather conditions such as rain and fog, and changes in the environment such as dirt on the cover and window of the ranging sensor unit 1, but in this case, the amount of light received changes slowly. In order to prevent the detection signal from being output due to such a gradual change in the light receiving amount, the light receiving amount storage unit 21 averages the light receiving amount R measured by the light receiving amount measuring unit 13 for a predetermined time a set in advance. , The average value is stored every predetermined time a, and the value obtained by multiplying the stored value by α (where α is a constant) is set as the threshold value 2.

FIG. 3 is a diagram showing an example of the relationship between the light receiving amount R, the threshold value 2, and the detection state in one embodiment of the present invention. Up to time t1, the change in the amount of light received due to changes in the environment is gradual, and after time t1, the change in the amount of light received due to a person entering the caution area is rapid.

Up to the time t1, the light receiving amount R measured by the light receiving amount measuring unit 13 is averaged in the light receiving amount storage unit 21 at a preset predetermined time a, and the average value is stored every predetermined time a, and the storage thereof is performed. Since the threshold value 2 is a value obtained by multiplying the value by α (however, α is a constant, for example, α = 0.25), the threshold value 2 also changes according to the fluctuation of the received light amount R, and the threshold value changes with a gradual change in the received light amount. Does not exceed 2 and does not output a detection signal. After the time t1, the threshold value 2 changes after the change of the light receiving amount R is completed, so that the light receiving amount R exceeds the threshold value 2, the detection state is set, and the detection signal is output.

Next, the detection state when the intruder stays in the caution area for a long time will be described.
In the present invention, during the detection signal output, the average value of the received light amount R is not used, the update work of the threshold value 2 is stopped, and the received light amount calculated based on the received light amount R after returning to the non-detection state. The update work of the threshold value 2 is restarted using the average value of R.

FIG. 4 is a diagram showing an example of the relationship between the light receiving amount R, the threshold value 2, and the detection state when an intruder exists in the caution area for a long time in one embodiment of the present invention. The solid line shows an example of the present invention, and the dotted line shows the case where the update work of the threshold value 2 is not stopped.

In both the present invention and the case where the update work of the threshold value 2 is not stopped, the change amount of the received light amount R exceeds the threshold value 2 at the time t2, the detection state is set and the detection signal is output, but the update work of the threshold value 2 is not stopped. Will return to the non-detection state at time t3, resulting in a false alarm state. However, in the present invention, the detection state is continued even after the time t3, and after returning to the non-detection state, the average value of the received light amount is started to be calculated again from the time t4, and the update of the threshold value 2 is restarted from the time t5.

Next, the detection state when an intruder slowly invades the caution area will be described.
In the present invention, a maximum value is set for the amount of change in the update of the threshold value 2.
FIG. 5 is a diagram showing an example of the relationship between the light receiving amount R, the threshold value 2, and the detection state when an intruder slowly invades the caution area according to the embodiment of the present invention. The solid line shows an example of the present invention, and the dotted line shows the case where the maximum value is not provided for the change amount of the update of the threshold value 2.

In both the present invention and the case where the maximum value is not set for the update change amount of the threshold value 2, the threshold value 2 is changed at time t6, but when the maximum value is not set for the update change amount of the threshold value 2, the threshold value 2 is changed. If the amount of change in the amount of light received R does not exceed the threshold value 2 and the amount of change in the amount of light received R continues to be close to the threshold value 2 even after the time t6, the detection signal is detected even though the total change in the amount of light received is large. Will be in a misreported state without outputting. However, in the present invention, since the change amount of the update of the threshold value 2 is limited to the maximum value b, the change amount of the received light amount R exceeds the threshold value 2 at the time t7, and the detection state is reached and the detection signal is output. it can.

Next, the optical axis adjustment method of the ranging type intrusion detection sensor of the present invention will be described.
As shown in FIG. 2, the distance measuring sensor unit 1 has a distance output unit 32 that can confirm the distance measured by the distance measuring unit 15 as a voltage value and a light receiving amount R measured by the light receiving amount measuring unit 13 as a voltage value. A light receiving amount output unit 33 that can be confirmed is provided. Either the distance output unit 32 or the light receiving amount output unit 33 is output to the optical axis adjustment output unit 34 by the switch 35, and can be read by a tester.

FIG. 6 is a graph showing an example of the relationship between the distance measured by the distance measuring unit 15 and the output voltage of the distance output unit 32 according to the embodiment of the present invention. The voltage value of the distance output unit 32 is a voltage value of 0.01 V per 0.1 m of the distance measured by the distance measurement unit 15. By checking the voltage value of the distance output unit 32, the distance measured by the distance measurement unit 15 becomes clear.

Further, the output range of the light receiving amount output unit 32 is set according to the distance measured by the distance measuring unit 15. Table 1 shows an example of the distance measured by the distance measuring unit 15, the light receiving amount measured by the light receiving amount measuring unit 13, and the output voltage of the light receiving amount output unit 33. The longer the measurement distance, the smaller the amount of light received can be confirmed by the output voltage.

First, the distance d (warning distance) between the installed distance measuring sensor unit 1 and the reflecting member 2 is measured and grasped in advance with a measure or the like.
The voltage value from the distance output unit 32 is output to the optical axis adjustment output unit 34 by the switch 35, and the distance measurement sensor is used by using the sighting device (not shown) provided in the distance measurement sensor unit 1. The unit 1 is directed toward the reflective member 2 and adjusted so that the voltage value of the optical axis adjusting output unit 34 becomes a voltage value corresponding to the value of the distance d measured in advance.

At that time, the range of the light receiving amount output unit 33 may be automatically switched, or may be switched by a push button switch or the like.
Next, when the voltage value from the light receiving amount output unit 33 is output to the optical axis adjustment output unit 34 by the switch 35, the direction of the distance measuring sensor unit 1 is finely adjusted, and the light receiving amount is maximized, The optical axis adjustment is completed.

In the optical axis adjustment method of the present invention, since the output range of the light receiving amount output unit 33 is set according to the warning distance, detailed and accurate optical axis adjustment is possible at any warning distance, malfunctions can be reduced, and stable detection performance is achieved. Can be demonstrated.

In the description of one embodiment of the present invention, each output is a voltage value, but a sound, a level meter, or an LED display may be used. Further, the output value may be confirmed from each of the distance output unit 32 and the light receiving amount output unit 33 without the optical axis adjusting output unit 34.

Although the embodiments of the present invention have been described above, the above-described embodiments are presented as examples, and the scope of the invention is not limited to this, and can be implemented in various other embodiments. It is included in the scope of the invention described in the claims and the equivalent scope thereof.

1 Distance measuring sensor unit 2 Reflecting member 3 Warning area 10 Distance measuring unit 11 Light emitting unit 12 Light receiving unit 13 Light receiving amount measuring unit 14 Light receiving and receiving control unit 15 Distance measuring unit 20 CPU unit 21 Light receiving amount storage unit 22 Distance storage unit 23 Signal Control / processing unit 30 Output unit 31 Detection signal output unit 32 Distance output unit 33 Received amount output unit 34 Optical axis adjustment output unit 35 Switch 101 Distance measurement type intrusion detection sensor 102 Warning area 103 Reflective member 104 Warning area 105 Intruder 106 Wall surface 107 optical path

Claims (6)

In a distance measuring type intrusion detection sensor composed of a distance measuring sensor unit having a light emitting part and a light receiving part and a reflective member having retroreflective properties.
The distance measuring sensor unit includes a distance measuring unit, a light receiving amount measuring unit, a distance storage unit, and a light receiving amount storage unit.
The distance from the sensor unit to the reflection member measured by the distance measuring unit is stored in the distance storage unit, and the light receiving amount measured by the light receiving amount measuring unit at that time is stored in the light receiving amount storage unit.
When the distance measured by the distance measuring unit changes from the stored distance beyond a preset threshold value 1, or the light receiving amount measured by the light receiving amount measuring unit is preset from the stored light receiving amount. A distance-measuring intrusion detection sensor that outputs an intrusion detection signal when the value exceeds the threshold value 2. The distance-measuring intrusion detection according to claim 1, wherein the threshold value 2 is a value obtained by multiplying the average value of the light receiving amount for a predetermined time a preset by α (however, α is a constant) and is updated every predetermined time a. sensor. During the detection signal output, the average value of the received light amount is not used, the update work of the threshold value 2 is stopped, and the average value of the received light amount calculated based on the received light amount after returning to the non-detection state. The ranging type intrusion detection sensor according to claim 2, wherein the update work of the threshold value 2 is restarted by using the above. The distance measuring type intrusion detection sensor according to claim 2 or 3 , wherein the update of the threshold value 2 is provided with a maximum value for the amount of change. A distance output unit that outputs the measured distance and a light reception amount output unit that outputs the light reception amount are provided.
The output range of the light receiving amount output unit is set by the distance measured by the distance measuring unit, and the output values of the distance output unit and the light receiving amount output unit are output by an independent output unit or an output unit that is switched and used. The distance measuring type intrusion detection sensor according to any one of claims 1 to 4 . The method for adjusting the optical axis of the ranging type intrusion detection sensor according to claim 5.
The distance between the distance measuring sensor unit and the reflecting member is measured and grasped in advance.
After roughly adjusting the direction of the sensor unit so that the output value of the distance output unit is the distance between the distance measurement sensor unit and the reflection member, the light reception amount is adjusted by the output value of the light reception amount output unit. An optical axis adjustment method for finely adjusting the direction of the distance measuring sensor unit.

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