JPH11213264A - Debris flow remote sensing system - Google Patents

Abstract

(57) [Summary] [Problem] To accurately detect the occurrence and scale of debris flow with high reliability. SOLUTION: A sensor unit 10 is installed at a place where debris flow is likely to occur, and a monitoring station unit 12 is installed at a safe remote monitoring center. The NaI scintillator 20 detects the environmental gamma dose, the detected level is amplified by the amplifier 24, and is compared with the threshold Vth by the comparison circuit 26. The video camera 32 is turned on by the debris flow detection output of the comparison circuit 26. The wireless transmission device 28 multiplexes the output of the amplifier 24 and the comparison result of the comparison circuit 28 with the video output of the video camera 32 and wirelessly transmits the output to the unit 12. In the unit 42, the radiation detection value is recorded by a time clock 44, and an alarm device 46 issues an alarm in response to the debris flow detection signal, and a monitor 48
Turn on the power. A video signal from the camera 32 is applied to the monitor 48.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a debris flow remote sensing system for remotely monitoring the occurrence (and scale) of a debris flow.

[0002]

2. Description of the Related Art In a conventional debris flow remote sensing system, a video camera is installed at a position where a debris flow is likely to occur (for example, a valley or the like), and the camera image is transmitted to a remote place by a wired or wireless method. A method of monitoring a hazardous place in a safe place, or a method of setting a wire so that it is cut by a debris flow generated at a place where debris flow is likely to occur, and transmitting the presence or absence of the wire to a remote location by wire or wireless Etc. are adopted. In addition, there is a method in which a person watching a place where a debris flow is likely to occur constantly monitors with a telescope.

[0003]

However, surveillance by a watchman entails a danger of life due to the need to approach danger points to some extent, and in the case where the surveillance points are not limited, a plurality of surveillance persons are required. The burden of labor costs is also large.

[0004] Remote monitoring using a video camera requires personnel who constantly monitor the monitor screen at a monitoring station.
Further, the occurrence of debris flow destroys equipment installed at the location where the debris flow has occurred, particularly a video camera and a transmission device of the camera image, but the cost becomes large. That is, this method requires a large amount of labor and equipment costs.
Water drops on the lens surface of the video camera and obstacles on the way are useless.

[0005] In the method of passing the wire sensor through the valley, the wire may not always be cut by the debris flow, and the cut by small animals or dead trees cannot be identified. That is, the debris flow sensor has problems in accuracy and reliability. Not only is it extremely difficult to wire across the valley, but you also cannot freely choose where to wire. The necessity of assuming the height of the debris flow and placing a wire lower than the height also makes it difficult to determine the installation location. Furthermore, once the wire is cut, the function stops, and the scale of the debris flow cannot be detected.

SUMMARY OF THE INVENTION It is an object of the present invention to solve such a problem and to provide a debris flow remote sensing system capable of detecting occurrence of debris flow with higher reliability.

Another object of the present invention is to provide a debris flow remote sensing system capable of detecting occurrence of debris flow with higher accuracy.

Another object of the present invention is to provide a debris flow remote sensing system that can be realized at a lower cost.

It is a further object of the present invention to provide a debris flow remote sensing system that can also sense the magnitude of the generated debris flow.

[0010]

According to the present invention, a natural radiation dose at a place where a debris flow is likely to occur is detected by a radiation detecting means, and the presence or absence of a debris flow is determined from the detected value. When debris flow is detected, a warning is issued from the warning means. As a result, a large number of dangerous points can be intensively monitored at a safe debris flow monitoring station. The magnitude of the debris flow generated can be estimated from the magnitude of the detected value.

The radiation detecting means can be used continuously even after the debris flow ends, as long as it is not destroyed by the debris flow. Therefore, the trouble of re-installation can be saved.

By using the radiation detecting means, small animals and fallen trees are not erroneously detected, and the accuracy and reliability are improved.

Since the environmental gamma dose is greatly increased by the debris flow, the debris flow can be accurately detected by using the environmental gamma ray detecting means as the radiation detecting means. Further, since the environmental gamma ray detecting means can be obtained at low cost, a system can be constructed at low cost.

By constituting the sensor unit with the radiation detecting means and the judging means, the handling becomes easy.
This is particularly useful when only the presence of debris flow is reported to a debris flow monitoring station.

By using the determination means as a comparison means for comparing the detection value of the radiation detection means with a predetermined threshold value, it is possible to easily determine whether or not a debris flow has occurred.

By using the wireless transmission means, it becomes easy to install the radiation detection means even in a steep place.

The radiation detecting means turns on a video camera installed at a location where a debris flow is likely to occur, and turns on the video display in response to the debris flow detection signal.
By providing the image display means for displaying the image of the camera, the state of the generated debris flow can be confirmed with the image.

By providing a control means for photographing the video camera in response to the debris flow detection signal, it is possible to take an image when it is really necessary and reduce power consumption.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic block diagram showing an embodiment of the present invention. This embodiment comprises a sensor unit 10 installed at a place where debris flow is likely to occur and a monitoring station unit 12 installed at a safe remote monitoring center, and both are wirelessly connected. Of course, the sensor unit 10 and the monitoring station unit 12 may be connected by wire. However, since the installation location of the sensor unit 10 is generally a dangerous place or a place where human beings are hard to step on, the wireless system is used. Is advantageous.

The sensor unit 10 includes a NaI scintillator 20 for detecting a natural radiation dose mainly containing environmental gamma rays (for example, 0.15 to 3.00 MeV). The NaI scintillator 20 has, for example, a diameter of 1 inch,
A 2 inch long NaI crystal 20a is placed in a photomultiplier tube 20b.
Of a light-incident surface. Power supply 22
Supplies the necessary power to the NaI scintillator 20, especially the photomultiplier tube 20b. The NaI crystal 20a emits light upon incidence of environmental gamma rays, and the photomultiplier tube 20b converts the generated light into a current. The NaI crystal 20a has higher sensitivity in the length direction than in the radial direction due to its size.

The amplifier 24 amplifies or current / voltage converts the output of the NaI scintillator 20 and applies it to one input of a comparison circuit 26. To the other input of the comparison circuit 26, a threshold value Vth for determining whether or not to alert is input. The value of Vth itself can be changed, and is determined to be a sufficiently large value by referring to the normal environmental gamma dose of the installation location. The output of the comparison circuit 26 is a binary signal indicating whether the output of the amplifier 24 is higher or lower than the threshold Vth. For example, when the output of the amplifier 24 is higher than the threshold Vth,
(High), otherwise L (low).

The output of the comparison circuit 26 is transmitted to a radio transmission device 28
And the output of the comparison circuit 26 for a certain time, for example, about 5 minutes,
It is applied to the holding circuit 30 for holding. The output of the holding circuit 30 is connected to the power supply control terminal of the video camera 32. When the output of the holding circuit 30 becomes H, the video camera 32 is turned on and outputs a video signal to be captured to the wireless transmission device 28. The video camera 32 is capable of shooting a wide range of places where debris flows are likely to occur,
Be placed. In recent years, since a cheap video camera can be obtained, the video camera 32 may be arranged close to the NaI scintillator 20. However, an expensive video camera is hardly affected by the generated debris flow. It may be installed in a safe place. This is because the problem can be solved by using a wide-angle shooting lens.

The output of the amplifier 24 is also
8 is also applied. The wireless transmission device 28 includes a comparison circuit 26
Is in the standby state while the output of L is L. In this standby state, the wireless transmission device 28 outputs a signal indicating the output level of the amplifier 24 to the antenna 34 and transmits the signal to the monitoring station unit 12. Thereby, in the monitoring station unit 12,
The output level of the NaI scintillator 20 can be continuously monitored. Further, the monitoring station unit 12 can know the failure of the sensor unit 10 and the like.

The monitoring station unit 1 stores the detected radiation value itself.
In the case of transmitting also to the monitoring station 2, by providing a circuit similar to the comparison circuit 26 in the monitoring station unit 12, the monitoring station can determine the presence / absence of debris flow with a unique threshold value. It is also useful for estimating the scale of the generated debris flow.

When the output of the comparison circuit 26 becomes H, the radio transmission device 28 outputs a signal indicating the occurrence of debris flow (debris flow detection signal).
Is output from the antenna 34 and the video camera 3
2 is also transmitted wirelessly. The detection value of the environmental gamma dose (output of the amplifier 24) may be wirelessly transmitted together with the debris flow detection signal. Thereby, the monitoring station unit 12
On the side, it is possible to determine whether the error is due to a malfunction or a failure.

Note that the radio transmitting device 28 is
Becomes high, the level of the video signal from the video camera 32 is also monitored, and the output of the comparison circuit 26 becomes low.
The output of the comparison circuit 26 and the video signal from the video camera 32 continue to be wirelessly transmitted to the monitoring station unit 12 while the video signal from the video camera 32 is present. When the output of the comparison circuit 26 is L and the video output from the video camera 32 disappears, for example, when the level of the video signal falls below a predetermined value, the wireless transmission device 28 enters a standby state.

Video camera 32 when debris flow occurs
By turning on the power supply, it is possible to take a truly necessary image and to minimize power consumption.

In the monitoring station unit 12, the radio signal from the sensor unit 10 is supplied to the radio receiving device 42 by the antenna 40. The wireless receiving device 42 supplies the measured amount of the environmental gamma ray (the output of the amplifier 24) to the time clock 44, and outputs the debris flow detection signal to the alarm device 46.
When the video signal is also received, the received video signal is supplied to the display monitor 48. The time recorder 44 records the time change of the measured environmental gamma dose on a recording sheet or as data on a recording medium. In a simple system, the function of wirelessly transmitting and recording the measured environmental gamma dose may be omitted.

The alarm device 46 generates an alarm (sound and light) and applies a power-on control signal to the display monitor 48 in response to the debris flow detection signal from the wireless receiving device 42. The power is turned on to the display monitor 48 by the power-on control signal, and the video camera 32 is turned on.
Is displayed on the screen of the display monitor 48.

The alarm device 46 stops outputting the alarm when the alarm output is manually turned off and when the debris detection signal is no longer input from the radio receiving device 42. The power to the monitor 48 is manually turned off.

The natural radiation dose, especially the environmental gamma dose, increases near the debris flow, and tends to increase as the scale of the debris flow increases. For example, the passage of debris flows usually doubles the environmental gamma dose. NaI crystal 2
0a is longer in the length direction than in the radial direction due to its size,
With higher sensitivity, the sensor unit 10,
In particular, if the NaI scintillator 20 is installed at a location where debris flow is likely to occur, the occurrence and stoppage of debris flow can be accurately detected, and the monitoring function is not lost even after the debris flow is stopped.

When the debris flow passes nearby, the output level of the NaI scintillator 20 increases according to the scale of the debris flow, and maintains the increased level while the debris flow is passing. By setting the threshold value Vth of the comparison circuit 26 to be smaller than the level increased by the passage of the debris flow, the occurrence of the debris flow can be wirelessly transmitted to the monitoring station unit 12.

In the wire sensor, once cut,
Although the monitoring function is stopped, the sensor unit 10 of this embodiment continues to have the monitoring function even after the debris flow is stopped unless the NaI scintillator 20 is damaged by the debris flow. That is, the sensor unit 10 can be continuously used,
Not only is it economical, but new sensors
Since the frequency of installing the unit 10 can be reduced, it can be said that the system is safer.

The environmental gamma dose is not affected by the weather,
Unaffected by small animals and dead trees. Further, since the debris flow can be detected even at night, the occurrence of debris flow can be monitored with high reliability and accuracy.

It is customary that the passage of the debris flow doubles the environmental gamma dose. In this embodiment, as an environmental gamma ray detection sensor, easy to handle, high sensitivity, and inexpensive Na
Since the I scintillator 20 is used, the cost can be reduced and an easy-to-use debris flow remote sensing system can be realized. The NaI scintillator 20 is sensitive to debris flow at a speed of 200 km / h. Although the wire sensor can detect only a debris flow having a height exceeding the stretched wire, in the present embodiment, such a restriction does not exist, so that the setting of the installation location is facilitated.

To record an image at the beginning of the debris flow, as shown in FIG. 2, a video signal output from the radio receiver 42 is delayed by a delay circuit 50 for a fixed time, and the output of the delay circuit is output to the VTR 52. May be recorded on a magnetic tape. By the debris flow detection signal output of the alarm device 46,
The VTR 52 starts recording. The recording of the VTR 52 may be stopped manually, but after the debris flow sensing signal is no longer output from the alarm device 46, the recording operation of the VTR 52 is stopped after waiting for a delay time of the delay circuit 50 or a time added to the delay time by a predetermined time. You may do so. This makes it possible to automatically record the video until the start and end of the debris flow on the recording medium.

In the above embodiment, the alarm device 46 outputs an alarm only when a debris flow is detected. However, if the measured dose of environmental gamma rays falls below a certain value, it is considered that the sensor unit 10 has failed. Therefore, at this time, an alarm indicating a failure of the sensor unit 10 may be issued.

Although the scale of the generated debris flow can be estimated from the duration of the debris flow detection signal, the instantaneous scale can be estimated if there is a radiation detection value.

[0040]

As can be easily understood from the above description, according to the present invention, the occurrence of debris flow can be remotely monitored at low cost, with high accuracy and with high reliability.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a first embodiment of the present invention.

FIG. 2 is a schematic block diagram of a modified embodiment of the present invention.

[Explanation of symbols]

 10: Sensor unit 12: Monitoring station unit 20: NaI scintillator 20a: NaI crystal 20b: Photomultiplier tube 22: Power supply 24: Amplifier 26: Comparison circuit 28: Wireless transmission device 30: Holding circuit 32: Video camera 34: Antenna 40: Antenna 42: Wireless receiver 44: Time recorder 46: Alarm device 48: Display monitor 50: Delay circuit 52: VTR

Claims (10)

[Claims] 1. A radiation detecting means for detecting a natural radiation dose, a determining means for determining whether or not a debris flow has occurred from a detection value of the radiation detecting means, and outputting a debris flow detection signal indicating the occurrence of the debris flow. Warning means for generating a warning in response to the debris flow detection signal output from the determining means, wherein the radiation detecting means is installed at a location for detecting a natural radiation dose in a place where a debris flow is likely to occur, and the warning means is provided. A debris flow remote sensing system installed at a debris flow monitoring station. 2. The debris flow remote sensing system according to claim 1, wherein said radiation detecting means is environmental gamma ray detecting means. 3. The debris flow remote sensing system according to claim 2, wherein said environmental gamma ray detecting means comprises a NaI scintillator. 4. The radiation detecting means and the determining means,
The sensor unit according to claim 1, wherein the sensor unit constitutes a sensor unit.
The debris flow remote sensing system according to the paragraph. 5. The apparatus according to claim 1, wherein said determining means comprises comparing means for comparing a detection value of said radiation detecting means with a predetermined threshold value.
The debris flow remote sensing system according to any one of claims 4 to 4. 6. The debris flow remote sensing system according to claim 1, further comprising wireless transmission means for wirelessly transmitting a detection value of said radiation detecting means to said debris flow monitoring station. 7. The wireless communication device according to claim 1, further comprising a wireless transmission unit configured to wirelessly transmit a detection value of the radiation detection unit and a determination result of the determination unit to the debris flow monitoring station.
The debris flow remote sensing system according to the paragraph. 8. A video camera, wherein the radiation detecting means is installed at a place where debris flow is likely to occur,
The debris flow remote sensing system according to any one of claims 1 to 7, further comprising: an image display unit that turns on an image display in response to the debris flow detection signal and displays an image of the video camera. 9. The debris flow remote sensing system according to claim 8, further comprising control means for causing the video camera to perform a shooting operation in accordance with the debris flow detection signal. 10. The remote sensing of debris flow according to claim 9, wherein the control means sets the video camera in a photographing operation state while the debris flow detecting signal is present and for a predetermined period after the debris flow detecting signal is lost. system.