JP3225719B2 - Mountainside displacement measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring system for detecting a collapse of a mountain slope or an artificially formed wall before the collapse occurs due to, for example, a natural disaster. The present invention relates to a hillside displacement measuring device that measures a distance to an observation point provided with a light reflector, obtains a displacement of the observation point, and measures a hillside displacement.

[0002]

2. Description of the Related Art It is extremely important in a public and social sense to detect in advance a landslide caused by a natural disaster such as an earthquake or heavy rain, for example.

FIG. 6 is an explanatory view of a conventional example of a displacement measuring method for detecting collapse of a mountainside in advance. In this figure, a prior indication of the collapse of the mountain slope is to be detected by a change in the distance between the two points A and B, and the distance between the two points A and B is measured by light. ing. That is, the light projected by the light projector 1 is received by the light receiver 2, the distance between the two points A and B is measured, and the measurement result is reported to an observation center or the like by the cable 3, for example. By performing distance measurement periodically,
The displacement of the distance between the two points A and B is calculated, and the hillside collapse can be detected in advance.

However, according to this method, a cable 4 for transmitting power supply power and control signals between the projector 1 and the receiver 2 is used.
It is necessary to lay the cable, the cost for fixing the cable along the slope of the mountain or the like increases, and there are many problems in terms of maintenance of the cable. There is also a similar problem with the cable 3 for transmitting power supply power and signals between the light receiver 2 and the observation center.

Further, in the method of FIG. 6, only the distance between the two points A and B can be measured, and the displacement at many points on the mountain slope cannot be detected. In order to detect the displacement, there is a problem that a large number of sets of a light emitter and a light receiver must be installed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hillside displacement measuring device capable of measuring displacement at many points on the hillside without laying cables on the hillside.

[0007]

FIG. 1 is a block diagram showing the principle configuration of the present invention. In the figure, a distance measuring means 11 projects light, receives light reflected by, for example, a light reflector, for example, each of which is installed at one or more observation points on a mountainside, for example, light reflected by a corner reflector, and extends to each light reflector. The distance is measured. Further, the light projection direction control means 12
It controls the direction of light projection by the distance measuring means 11.

The image recognition and direction indicating means 13 recognizes an image indicating the position of each light reflector installed at one or more of the above-mentioned observation points, for example, an infrared image, and controls the light projection direction according to the recognition result. A direction instruction signal is output to the means 12 so that the direction of light projection by the distance measuring means 11 matches the direction toward the light reflector.

Further, in the present invention, the distance measuring means 11
The displacement of the observation point is obtained by the change in the distance to the light reflector measured by the above, and an alarm display device that displays an alarm when the displacement exceeds a predetermined value is further provided. Signs can be detected.

[0010]

In the present invention, for example, a plurality of light reflectors, for example, corner reflectors are installed over the entire hillside,
By projecting, for example, a laser beam pulse having a high directivity from the distance measuring unit 11 and measuring the time until the light pulse reflected from each light reflector is received, the distance to each light reflector is obtained, Thus, the displacement of each observation point is obtained.

In order to correctly control the projection direction of the laser light to the direction to each light reflector, an infrared image covering, for example, all the light reflectors is obtained from the image recognition and direction indicating means 13. The projection direction of the laser light pulse is controlled using the recognition result of the image.

For example, by sequentially and periodically measuring the distance to each light reflector, it becomes possible to periodically obtain information on the displacement of the entire hillside. It is also easy to add light reflectors to other observation points as needed.

[0013]

FIG. 2 is a block diagram showing the overall configuration of a hillside displacement measuring apparatus according to the present invention. In the figure, the hillside displacement side low device is
A distance measuring device 20 and a distance measuring device 20 that roughly measure the distance to the light reflector 50 installed at each observation point
Control device 25 for controlling the direction of light projected from the device, an infrared light image indicating the position of the light reflector 50 is obtained and the image is recognized, and the direction control device 25 is notified of the distance measurement device 20 And an image recognition and direction indicating device 30 that outputs a direction indicating signal so that a light pulse projected from each of the light reflectors 50 correctly travels to each light reflector 50, and issues an alarm when the displacement of the observation point exceeds a predetermined value. It comprises an alarm display device 40 for displaying.

The distance measuring device 20 includes, for example, a light projecting unit 21 for projecting a projection light pulse 41 as a laser beam, a light receiving unit 22 for receiving a reflected light pulse 42 from a light reflector, and a laser beam from the light projecting unit 21. After the pulse is projected, light receiving unit 2
2 comprises a signal processing circuit 23 for converting the time until the reflected light pulse is received into a distance.

As the light projected by the light projecting unit 21, a laser beam having a high directivity is suitable, but if the directivity is good, for example, an LED or the like can be used as a light source. The light reflector 50 is generally installed at a plurality of observation points where displacement is to be measured on the hillside, and its main body is, for example, a corner reflector 51 composed of three mutually perpendicular reflecting surfaces, A corner reflector 51 is provided by a cover 52 for preventing dirt due to earth and sand.
Is covered.

The direction control device 25 comprises a control circuit 26 for receiving a direction instruction signal 43 output from the image recognition and direction instruction device 30, and a drive mechanism 27 for directing the distance measurement device 20 to a specific reflector. Have been.

The image recognition and direction indicating device 30 receives infrared reflected light from an infrared light projecting unit 31 for projecting infrared light, for example, a plurality of light reflectors installed over the entire mountainside. Based on the infrared light receiving unit 32 and the infrared light image obtained by the infrared light receiving unit 32, that is, the image indicating the positions of the plurality of light reflectors, the direction indicating signal 43 indicating the direction of each reflector is provided in the direction. And an image recognition circuit 33 provided to the control device 25. The projection area of the infrared light projected from the infrared light projection unit 31 is set to include all of the plurality of light reflectors 50 installed on the hillside surface, and accordingly, the infrared light reception area of the infrared light reception unit 32 is set. Includes all of the plurality of light reflectors, and an infrared image showing the positions of all the light reflectors 50 is obtained.

The image recognition circuit 33 is provided with a direction indication signal 4
The measurement result of the distance to the light reflector 50 indicated by 3 is received from the distance measurement device 20 as the distance output signal 44 and stored as measurement data, and the data is compared with the previous measurement data, and is determined in advance. If the displacement is exceeded, an alarm signal 45 is output to the alarm display device 40.
Output to

FIG. 3 shows a light reflector 50 from the distance measuring device 20.
It is an explanatory view of a measuring method of a distance to an observation point where is installed. In the figure, for example, corner reflectors R _{1 to} R ₃ are respectively installed at three places A _{1 to} A ₃ on the mountainside, and each observation point A is set from the installation point S ₀ of the distance measuring device 20.
The initial value of the distance to ₁ to A ₃ and l ₁ to l _3. The projection light from the distance measuring device 20 is directed to the direction control devices 25 so as to face the respective corner reflectors R _{1 to} R _3.
Are controlled sequentially.

[0020] Measurements of the distance is performed periodically, for example 1 was measured in the following week, the distance from the point S ₀ to corner reflectors R ₁ to R ₃ has changed to l ₁ '~l _3' Then, the observation points where the respective corner reflectors are installed have changed from A ₁ ′ to A ₃ ′ as shown in the figure. Whether or not to output an alarm is determined based on whether or not the displacement of each observation point exceeds a preset value.

FIG. 4 is a detailed explanatory view of the hillside displacement measuring method according to the present invention. The figure shows a state in which, for example, nine light reflectors R _{1 to} R ₉ are installed over the entire mountainside surface. Each light reflector is, for example, 3
Is a corner reflector composed of two reflective surfaces,
The property that reflected light returns in the same direction as the direction in which the light is projected is used. Therefore, for the light pulse projected from the distance measuring device 20, only the reflected light pulse from a specific one of the plurality of corner reflectors can be received. In FIG. 4, the state in which the distance to the light reflector R ₅ is measured is shown.

On the other hand, the image recognition and direction indicating device 30
Infrared light is projected over the entire hillside as an infrared light projection area, infrared light reflected from each corner reflector is received, and an image indicating the position of each corner reflector can be obtained. From this image, each corner reflector can be obtained. R _{1 to} R
Information about the direction to ₉ is calculated, and the direction of the light projected from the distance measurement device 20 is controlled by the direction control device 25 based on the calculation result.

The reason why infrared light is used in the image recognition and direction indicating device 30 is to facilitate separation of reflected light and background light even in the daytime. By using infrared light, measurement can be performed regardless of day or night. For example, light other than infrared light can be used if the intensity of the projected light is modulated to facilitate separation from the background light, and if the S / N ratio can be sufficiently increased.

FIG. 5 is a detailed explanatory diagram of a distance measuring method using a light pulse. In this figure, it is assumed that light projection is performed at regular time intervals. At a certain time, an interval t ₁ between the projection time of the projected light pulse I and the time of receiving the corresponding light receiving pulse P ₁ matches the time interval of N clocks of a certain frequency f _1. I do. The displacement occurs in the observation point, it is assumed that the light receiving pulse is received by the time indicated in P ₂ shown in the figure, the time interval t ₂ from the time of light pulses projected a match clock N time intervals of the frequency f ₂ Shall be done. In this case, the following equation using displacement Δl difference Δt (= t ₂ -t ₁₎ of t ₂ and t ₁ and a speed C of light

[0025]

(Equation 1)

When Δt is represented by a frequency difference Δf = f ₂ −f ₁ ,

[0027]

(Equation 2)

From

[0029]

(Equation 3)

## EQU1 ## Here, Δf≪f ₁ (that is, Δt
≪t ₁ , Δl≪l)

[0031]

(Equation 4)

The displacement Δl is given by the following equation.

[0033]

(Equation 5)

The value in parentheses in the expression (5) is an amount determined by the frequency f ₁ before the displacement, and the displacement Δl is obtained by measuring the change Δf of the frequency f. Frequency measurement is easy and accuracy of 10 ^-6 can be easily obtained.

For example, when l ₁ = 300 [m] and N = 10, the clock frequency becomes

[0036]

(Equation 6)

Is as follows. Assuming that a change of Δf = f [H _Z ] occurs, from equation (5)

[0038]

(Equation 7)

It can be seen that the distance was shortened by 0.3 [mm]. The reference of how much the displacement should be before issuing an alarm can be set in advance.

[0040]

As described above in detail, according to the present invention, it is not necessary to lay cables or the like on the hillside, and it is possible to measure the distance to the light reflectors respectively installed at a plurality of observation points. It becomes possible to automatically measure the displacement of the entire hillside without increasing the cost. This makes it possible to detect in advance the collapse of a mountainside or an artificially made wall, etc., and to display a warning by comprehensively judging the displacement of each observation point.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the principle configuration of the present invention.

FIG. 2 is a block diagram showing the overall configuration of the hillside displacement measuring device of the present invention.

FIG. 3 is a diagram illustrating a method of measuring a distance.

FIG. 4 is an explanatory diagram of a hillside displacement measuring method.

FIG. 5 is a diagram illustrating a distance measuring method using a light pulse.

FIG. 6 is an explanatory diagram of a conventional hillside displacement measuring method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Distance measurement means 12 Light projection direction control means 13 Image recognition and direction indication means 20 Distance measurement device 21 Light projection unit 22 Light reception unit 23 Signal processing circuit 25 Direction control device 26 Control circuit 27 Drive mechanism 30 Image recognition and direction indication device 31 Infrared light projecting part 32 Infrared light receiving part 33 Image recognition circuit 40 Alarm display device 50 Light reflector 51 Corner reflector

Continuation of the front page (56) References JP-A-63-196809 (JP, A) JP-A-2-128114 (JP, A) JP-A-4-178514 (JP, A) JP-A-4-290915 (JP) , A) Tokuho 5-45883 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 15/00

Claims (4)

(57) [Claims] A distance measuring means for projecting light, receiving light reflected by light reflectors installed at one or more observation points, and measuring a distance to each of the light reflectors. A light projection direction control means (12) for controlling a light projection direction by the distance measuring means (11); and an image indicating a position of each light reflector installed at the one or more observation points. An image for outputting a direction instruction signal to the light projection direction control means (12) based on the recognition result such that the light projection direction by the distance measurement means (11) matches the direction to each light reflector. A hillside displacement measuring device comprising a recognition and direction indicating means (13). 2. An alarm which displays an alarm when the displacement of any of the one or more observation points measured by the distance measuring means (11) exceeds a predetermined value. The hillside displacement measuring device according to claim 1, further comprising a display device (40). 3. A light projecting unit (2) for projecting a laser beam pulse having high directivity as the light.
1); a light receiving unit (22) for receiving a reflected light pulse reflected by the light reflector; and measuring a time from the light projection by the light projecting unit (21) to the light receiving by the light receiving unit (22). 2. A hillside displacement measuring apparatus according to claim 1, wherein the signal processing circuit determines a distance to the light reflector, and the light reflector is formed by a corner reflector. . 4. The image recognition and direction designating means (1)
3) an infrared light projector (3) that projects infrared light to a range including at least two or more of the one or more observation points.
1); an infrared light receiving section (32) for receiving infrared light reflected from the light reflector as an image indicating the position of the reflector; and a reflection obtained by the infrared light receiving section (32). Recognizing the image indicating the position of the body, and controlling the light projection direction (12)
The hillside displacement measuring device according to claim 1, further comprising an image recognition circuit (33) for outputting a direction instruction signal to the hillside displacement measuring device.