JPH0723850B2 - Tunnel inner surface property detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to unevenness, cracks (cracking) and crevices (steps) along the cracks generated on the wall surface of tunnels used for headraces, roads, railways, etc. The present invention relates to a tunnel inner surface property detecting device for accurately detecting defects such as wear.

[Conventional technology]

Many of the waterway tunnels have deteriorated about 50 years after construction, and if an accident such as destruction occurs, it will hinder the power supply and have a great impact on the public. In addition, tunnels such as roads and railroads are aging, and if an accident such as destruction occurs, there is a risk of human life. Under such circumstances, inspection and inspection of tunnels are extremely important.

By the way, as a conventional method for detecting defects such as unevenness, cracks, crosses, and wear on the tunnel wall surface, several inspectors entered the tunnel in the dark and lit the wall with light such as electric lights. However, it was mainly done by visual confirmation such as sketching or taking a picture.

Other detection methods include, for example, JP-A-60-49260.
As shown in the publication, the ultrasonic transmission / reception sensor is closely attached to the inner surface of the tunnel lining to emit ultrasonic waves, and by measuring the propagation time until the reflected wave from the outer surface of the lining is received, the strength of the tunnel lining and the There is a way to estimate the dimensions.

[Problems to be solved by the invention]

However, the above-mentioned visual confirmation method has different judgments depending on the person depending on the number of years of experience of the inspector and differences in subjectivity, etc. Had various problems such as requiring a lot of labor such as increasing the number of inspectors.

In addition, the above-mentioned method using ultrasonic waves is intended to estimate the strength and size of the lining, and the following problems occur even if this method is applied to the detection of the inner surface properties of tunnels. It is thought that. That is, in this ultrasonic method, since it is necessary to bring the ultrasonic transmission / reception sensor into close contact with the inner surface of the lining, the ultrasonic transmission / reception sensor should be rotated along the tunnel circumferential direction and moved forward in order to measure the entire tunnel. Then, there is an inconvenience that it takes a lot of time for measurement. Also, the wall surface of the tunnel is usually made of concrete, but the ultrasonic wave propagation characteristics in concrete are much worse than that of steel, so when applying this ultrasonic method to detect the properties of the tunnel, There is a problem that the measurement accuracy deteriorates, and that the measurement accuracy also depends on the variation of the contact state of the sensor due to the unevenness of the wall surface.

[Means for solving problems]

Therefore, the present invention is directed to a laser scanning means arranged at a predetermined position of a vehicle for rotating and scanning a laser beam in a direction perpendicular to the longitudinal axis of the vehicle, and an imaging for imaging a scanning locus of the laser beam on a tunnel wall surface. Means, light receiving means for receiving scattered light of the laser beam on the tunnel wall surface, position detecting means for detecting a moving position of the vehicle along the tunnel longitudinal direction, output of the image pickup means, and light reception of the light receiving means. A recording unit that records the output and the detection output of the position detecting unit together with the vehicle is installed, and defects such as irregularities, cracks, and claws along the crack formed on the tunnel wall surface are detected based on the recorded contents of the recording unit. To do so.

[Action]

The laser scanning means two-dimensionally scans the laser beam along the inner circumferential surface of the tunnel, and the laser scanning means is moved in the longitudinal direction of the tunnel as the vehicle advances, whereby the entire wall surface of the tunnel is irradiated with the laser beam. At the same time, the scanning locus of the laser beam on the tunnel wall surface and the scattered light are picked up and received by the image pickup means and the light receiving means mounted on the vehicle, respectively. The imaging output and the scattered light reception output are recorded in the recording means together with the position data along the tunnel longitudinal direction of the vehicle detected by the position detection means, and then the recorded contents are processed into data, for example, into a two-dimensional graph. Image data or scattered light reception data on the entire wall surface of the tunnel is obtained by displaying or printing out an image. The output of the light-receiving means has a significantly reduced light-receiving output due to a shadow effect in the presence of cracks, so by discriminating the scattered-light received data displayed or printed out, the crack generated on the tunnel wall surface can be detected. The size, position, shape, etc. can be detected in detail. Further, defects such as unevenness, dents and wear formed on the wall surface of the tunnel can be detected by analyzing the imaging data.

〔Example〕

FIG. 1 shows a laser beam scanning system 1 according to an embodiment of the present invention.
Is shown conceptually. In the scanning system 1, when the laser beam L is incident from the laser projector 5 onto the mirror 4 fixed to the mirror holder 3 which is rotated in the arrow direction by the electric motor 2, the laser beam L is moved by the mirror 4 in the incident direction. It is reflected in the vertical direction, and then the mirror holder 3
It is incident on the tunnel wall surface 8 through the window portion 6 and scans the tunnel wall surface 8 in the circumferential direction. Therefore, if the laser beam L is emitted from the laser projector 5 so as to be parallel to the longitudinal direction of the tunnel wall surface, the laser beam L
After being reflected by the mirror 4, it will enter the tunnel wall surface 8 vertically. Further, the laser beam L incident on the tunnel wall surface 8 substantially vertically is then reflected vertically to the wall surface 8 and scattered. The scanning system 1 includes a plurality of light receiving sensors 9-1, ... 9-n including photomultipliers and the like, and the plurality of light receiving sensors 9-
The laser beam L scattered by the wall surface 8 is received by 1, ... 9-n. In addition, the laser beam reflected by the mirror 4 is rotated once in the half mirror 7 during one rotation.
The laser beam reflected by the half mirror 7 is incident on the light receiving sensor 10 including a photodiode or the like. Therefore, the light receiving sensor 10
Detects the beam every time the laser beam L is scanned once by the rotation of the mirror holder 3. The light receiving sensor 10 is used for detecting the start end of laser rotation scanning.
Further, in the scanning system 1, since the trajectory of the rotationally scanned laser beam on the tunnel wall surface is imaged,
Multiple TV cameras using CCD image sensor etc. 1
1-1, ... 11-n are provided, and the plurality of cameras 11-1,
The tunnel wall surface 8 can be imaged over the entire circumference by 11-n.

FIG. 2 shows the electric motor 2, the mirror holder 3, the mirror 4,
1 shows a measurement vehicle in which a laser beam scanning system 1 including a laser projector 5, a half mirror 7, a light receiving sensor 10 and the like is housed in casings 12 and 14 provided above a driver's seat, and a laser beam L is a casing 12 It is radiated through the window 13 formed in the tunnel and then reflected on the tunnel wall surface.

In this case, two light receiving sensors 9-1 and 9-2 for receiving the scattered light on the tunnel wall surface of the laser beam are provided on the left and right in front of the casing 14 arranged in the upper part of the vehicle, and the light receiving sensor 9 is also provided. -1, 9-2, two television cameras 11-1, 11- for imaging the laser beam trajectory
Two TV cameras 11-3, 11 are provided on the left and right of the bumper of the vehicle to capture the trajectory of the laser beam.
-4 is provided. That is, in this case, the two light receiving sensors 9-1 and 9-2 receive the laser scattered light on the tunnel wall surface, and the four television cameras 11-1, ... 11-
The laser trajectory of the entire circumference of the tunnel is imaged by 4. In addition, this vehicle has a mileage measuring device that outputs a number of pulse signals proportional to the mileage to the left rear wheel 15 in order to detect the vehicle position along the longitudinal direction of the tunnel. A pulse generator 16 (see FIG. 3) is attached.

FIG. 3 is a block diagram showing an electric circuit of this embodiment, and the operation of this embodiment will be described below with reference to FIG.

First, the detection of defects such as irregularities formed on the wall surface of the tunnel, differences, abrasion (water channel tunnel), etc. will be described.

When the measurement operation is started, the controller 23 drives the electric motor 2
The master lock signal is input to the motor 2
Is operated at a constant speed.

When the mirror holder 3 is rotated by the electric motor 2, the laser beam is rotationally scanned on the tunnel wall surface 8. The light receiving sensor 10 receives the laser beam L each time the laser beam L is scanned once, and applies the received light output to the synchronizing circuit 17 and the signal processing circuit 24 as a rotation start end position signal.
The synchronizing circuit 17 divides the input rotation start position signal having a predetermined frequency into a signal having a frequency of 60 Hz, and outputs the divided output to the signal processing circuit 18 as a synchronizing signal. When the scanning locus of the beam is formed on the wall surface of the tunnel by the scanning of the laser beam, the scanning locus of the entire circumference of the tunnel is divided by the plurality of television cameras 11-1, ... Is imaged.

Now, assuming that the vehicle is traveling at 10 km / h, as shown in FIG. 4, the traveling distance of the vehicle in 1/60 seconds is about 4.
It will be 6 cm. Here, set the readout frequency of each TV camera to 6
When the frequency is 0 Hz, the laser beam is scanned a predetermined number of times (for example, 2880 times) while the vehicle travels 4.6 cm, so the number of times the image is written to the camera during this read cycle is 48 times (2880/60). As a result, a plurality of 48 beam scanning loci are drawn close to each other on the image pickup surface of each camera. In this case, when the image data is read from the television camera, the average value of the plurality of images is read at the TV rate.

In this way, the plurality of television cameras 11-1, ... 11-n
The respective image pickup data read out from the above are added to the signal processing circuit 18, where the image pickup data of the entire circumference of the inner surface of the tunnel is formed by performing a combining process or the like, and then recorded in the VTR (video tape recorder) 19. Note that the image pickup surface of the camera can be temporarily stored and integrated, and the above reading is performed on the image data written on the image pickup surface one field before. Further, the above-mentioned read processing is performed in synchronization with the synchronizing signal from the synchronizing circuit 17.

In addition, as the vehicle travels, a pulse generator for distance measurement 16
The number of pulse signals that are proportional to the distance traveled by the vehicle is output from and is input to the correction circuit 20. The correction circuit 20 performs processing such as thinning / addition of input pulses for error correction based on vehicle inclination or slip, and outputs one pulse each time the vehicle travels 1 mm. mm pulse signal to PCM (Pulse Code Modulation) circuit 21
Output to. The PCM circuit 21 integrates and codes the input pulse signal of 1 pulse / mm. Therefore, the mileage data of the vehicle is output from the PCM circuit 21, and the mileage data is input to the VTR 19.

Then, the distance data from the traveling start point is sequentially recorded in the VTR 19 together with the image pickup data. It is also possible to record audio data from the microphone 22 at the same time, and image data is recorded on the video track, and traveling distance data and audio data are recorded on the audio track.

As described above, the image pickup data recorded in the VTR 19 is thereafter stored in a dedicated image memory (not shown) by off-line processing, and then subjected to appropriate signal processing and then, for example, displayed or printed out as an image. The inspector detects defects such as irregularities formed on the wall surface of the tunnel, crosses (steps) along the cracks, wear (water channel tunnel), etc. based on the display or the printing result.

Next, the measurement of cracks will be described. As shown in FIG. 5 (a) or (b), when there is no crack on the road surface irradiated with laser light, a predetermined amount of scattered light is incident on the photodetector 9. If there is a crack CR on the road surface as shown in Figure (c),
The so-called shadow effect significantly reduces the amount of light incident on the light receiver 9. Note that FIG. 5 (a) shows a case where the wall surface is smooth, and FIG. 5 (b) shows a case where the wall surface is rough. Therefore, assuming that FIG. 6 (a) is a rotation start end position signal output from the light receiving sensor 10, when a crack exists on the wall surface, as shown in FIG. 6 (b), the laser scanning beam indicates a cracked portion. The output of the light receiver 9 decreases at the time of passage, and the position of the signal indicating the decrease in output corresponds to the position of the crack in the circumferential direction of the wall surface. The photodetector 9 for detecting the wall-scattered light of the laser beam L is arranged at a position where an optimum shadow action can be obtained.

In FIG. 3, when the laser beam L is scanned, a plurality of light receiving sensors 9-1, 9-2, ... 9 provided above the vehicle.
In -n, scattered light from the tunnel wall surface is received, and the time-series received light output is input in parallel to the signal processing circuit 24. The signal processing circuit 24, based on the rotation start end position signal input from the light receiving sensor 10, receives the plurality of light receiving sensors 9-1, ...
The plurality of pieces of laser scattered light amount data input from 9-n are added to synthesize the plurality of pieces of light amount data, and the added output is input to the VTR 25.

In addition to the laser scattered light amount data, the VTR25 also contains the P
The traveling distance data from the CM circuit 21, the voice data from the microphone 22 and the sampling pulse signal from the correction circuit 20 are input. In the correction circuit 20, in addition to outputting the above-mentioned pulse signal of 1 pulse / mm to the PCM circuit 21, based on the pulse signal input from the pulse generator 16,
A pulse signal (see FIG. 6 (c)) consisting of a large number of equally spaced pulse trains corresponding to the data sampling pitch (eg, 1 mm pitch) for the entire circumference in the tunnel crossing direction is formed, and this pulse signal is input to the VTR 25. . This pulse signal is used as a signal indicating the sampling interval of the scattered light data output from the signal processing circuit 24, and the scattered light data is sampled at time intervals corresponding to the frequency of the pulse signal.

Then, in the VTR 25, the scattered light data input from the signal processing circuit 24 to the video track is recorded according to the sampling interval pulse signal input from the correction circuit 20, and in the audio track from the PCM circuit 21. The input traveling distance data and voice data from the microphone 22 are recorded according to a predetermined format.

In the above description, the cracks are detected at the 1 mm pitch in the longitudinal direction of the tunnel along the entire circumference in the transverse direction, but the desired measurement and sampling pitch, for example, 0.5 mm pitch in the longitudinal direction of the tunnel (1 pulse / 0.5 mm (Signal) and measurement at a sampling pitch of 0.5 mm in the transverse direction are also possible by the output signal switching function provided in the correction circuit 20.

The series of operations described above is controlled by the controller 23.

As described above, the scattered light data recorded in the VTR 25 indicating the cracks on the tunnel wall surface is stored in the dedicated image memory by the offline processing together with the traveling distance data.

For example, the scattered light data for crack detection and the traveling distance data recorded in the VTR 25 are read by the reading circuit 26 and input to the writing control circuit 27. This write control circuit 27
In order to control the address when storing the scattered light data and the traveling distance data in the image memory 28, the data is stored in the image memory 28 in the manner shown in FIG. In the figure, the X direction is the tunnel traveling direction, and the Y direction
The direction corresponds to the transverse direction, and the Z direction is the scattered light data on the wall surface indicated by the X and Y addresses. The X-direction address indicates the traveling distance of the vehicle, and the Y-direction address indicates the traveling distance of the laser light, that is, the circumferential distance of the tunnel wall surface. The data stored in the image memory 28 is binarized by the image processing circuit 29 by the threshold value Ls shown in the figure, and data below the threshold value Ls is used as crack data, and the crack position is determined based on this crack data. Incidentally, in the example shown in FIG. 7, the hatched portion corresponds to the crack.

The image processing circuit 29 applies predetermined signal processing such as image enhancement and scaling to the data stored in the image memory, and then outputs the data to the printer 30 to make a hard copy, or a screen display on the CRT 31. Or magnetically record on the magnetic tape 32.

FIG. 8 shows the appearance of the apparatus of this embodiment applied to a waterway tunnel or a road tunnel, and FIG. 9 shows the appearance of the apparatus applied to a railway tunnel.

Note that the configuration for rotationally scanning the laser beam toward the tunnel wall surface is not limited to that shown in the above-mentioned embodiment, and, for example, a polygon mirror or the like may be used to achieve the same function. .

Further, if the apparatus is made more compact, the present invention can be applied to the detection of cracks on the inner wall surface of a sewer pipe, a conduit for electric wires, a pipeline or the like.

〔The invention's effect〕

As described above, according to the present invention, the laser scanning means two-dimensionally scans the laser beam along the inner circumferential surface of the tunnel, and the laser scanning means moves in the tunnel longitudinal direction as the vehicle advances. The entire wall surface of the tunnel is irradiated with the laser beam by means of the imaging means, and the scanning locus of the laser beam on the tunnel wall surface is imaged by the imaging means and the scattered light of the laser beam on the tunnel wall surface is received by the light receiving means mounted on the vehicle. The imaging output and the scattered light reception output are recorded in a recording means together with position detection data along the longitudinal direction of the vehicle, and defects such as unevenness, crossing, wear and cracks on the tunnel wall surface are detected based on the recorded data. Therefore, defective parts can be detected efficiently and accurately, and the cost and labor required for detection can be greatly reduced. It can be reduced. Further, since the data is recorded in the recording means, data processing and analysis by a computer or the like can be facilitated, and the processing speed and accuracy can be increased.

[Brief description of drawings]

FIG. 1 is a side view conceptually showing a configuration example of an optical system of a tunnel inner surface texture detecting device according to the present invention, and FIG. 2 is a perspective view showing a measurement vehicle equipped with the tunnel inner surface texture detecting device of the present invention, FIG. 3 is a block diagram showing an electric circuit of a tunnel inner surface property detecting device according to the present invention, FIG. 4 is a perspective view showing an image pickup mode of a television camera, and FIG. 5 is a reflection of a laser beam on a tunnel wall surface. Fig. 6 shows a mode, Fig. 6 is a waveform diagram showing an output waveform of an optical sensor when a crack is present on the road surface, and Fig. 7 shows a mode in which data about the crack is stored in an image memory. Conceptual diagram showing the eighth
FIG. 9 is a perspective view showing the appearance of the present invention applied to a water channel or road tunnel, and FIG. 9 is a perspective view showing the appearance of the present invention applied to a railway tunnel. 1 ... Laser beam scanning system, 2 ... Electric motor, 3 ... Mirror holder, 4 ... Mirror, 5 ... Laser projector, 6,12 ...
… Window, 7 …… Half mirror, 8 …… Tunnel wall, 9,10
…… Light receiving sensor, 11 …… TV camera, 12,14 …… Casing, 16 …… Distance measuring pulse generator, 17 …… Synchronizing circuit, 18,24 …… Signal processing circuit, 19,25 …… VTR, 20 ... Correction circuit, 21 ... PCM circuit, 22 ... Microphone, 23 ... Controller, 26 ... Read circuit, 27 ... Write control circuit, 28 ...
Image memory, 29 ... Image processing circuit, 30 ... Printer, 31
…… CRT, 28 …… Magnetic tape.

Claims (1)

[Claims] 1. A laser scanning means which is arranged at a predetermined position of a vehicle and which rotationally scans a laser beam in a direction perpendicular to a longitudinal axis of the vehicle, and an imaging device for imaging a scanning locus of the laser beam on a tunnel wall surface. Means, light receiving means for receiving scattered light of the laser beam on the tunnel wall surface, position detecting means for detecting a moving position along the tunnel longitudinal direction of the vehicle, output of the image pickup means, and light reception of the light receiving means. A tunnel inner surface property detecting device comprising: a recording means for recording the output and the detection output of the position detecting means in a vehicle.