JPH0823259B2 - Borehole automatic crack measuring device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a borehole automatic crack measuring device suitable for use in a geological survey of rock or ground in the field of civil engineering and construction.

[Conventional technology]

The investigation of cracks in boreholes is a basic investigation item in the geological investigation work of rock and ground.

Conventionally, when excavating underground cavities such as dams and tunnels, it is necessary to conduct a geological survey of the construction site, reflect it in the design, and make sure to select the construction method to be adopted, the method of construction work, safety measures, etc. Is. In the geological survey in such a case, it is generally necessary to know the direction, slope and properties of the fractures in the rock, as well as the direction and slope of the formation. For this reason, investigations have been conducted by boring the construction site and observing the core, or by directly observing the bore wall of the borehole.

[Problems to be solved by the invention]

However, in the conventional crack investigation as described above, it takes a considerable period of time from the investigation plan to the report, and the accuracy of the distribution, direction, and width of the crack and the measurement points and the number of cracks depend on the skill and personality of the investigator. Since the difference depends on the difference, the data storage method of the crack investigation result cannot be unified, the data preservation is incomplete, and it is difficult to make a time-series study such as comparison with the investigation result conducted previously. In addition, the current image input / processing /
The recording device has a problem that it cannot be put to practical use because the storage capacity required for recording data is enormous.

The present invention is to solve the above-mentioned problems, and to provide a borehole crack automatic measuring device capable of performing a borehole crack investigation with a simple operation and obtaining survey data with constant accuracy without individual differences. With the goal.

[Means for solving problems]

Therefore, the automatic crack measuring device for a borehole of the present invention is an automatic crack measuring device for a borehole that measures a crack by processing image data obtained by imaging the wall surface of the borehole, and moves up and down along the wall surface of the borehole. A scanner built in the sonde for acquiring image data of the wall surface, a binarizing means for binarizing the image data by setting a threshold value, and thinning for obtaining the center line of the pixel group in which the binarized data are connected. The present invention is characterized by comprising processing means, vectorization means for vectorizing the center line, and crack detection means for detecting crack information from the vectorized center line and image data.

[Action]

In the automatic crack measuring device for a borehole of the present invention, the light and dark image data obtained by imaging the wall surface of the borehole is binarized, and the center of the cracked portion is obtained by obtaining the center by the thinning processing means for the connected pixel group. A line is required. The vectorizing means vectorizes the center line of the crack portion, and the crack detecting means detects the crack width and other crack information in vector units. Noise such as dirt and scratches can be effectively removed through each step of the series of processes.

〔Example〕

 Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1 is a diagram showing a state of use of an automatic crack measuring device for a borehole according to the present invention, FIG. 2 is a diagram showing a concrete configuration example of an image input device, and FIG. 3 is a hole scanned by a light beam. FIG. 4 is a diagram showing the locus of the wall development surface, and FIG. 4 is a diagram for explaining the detection angles of the azimuth meter and the inclinometer. In the figure, 1 is an image input device (imaging unit), 2 is a main unit, 3 is a winch for hoisting the image input device, 11 is a borehole, 12 is a sonde, 13 is a turning motor, 14 is a direction indicator, and 15 22 is a lens, 16 is a mirror, 17 is an optical head, 18 and 21 are slits, 19 is a photoelectric converter, 20 is a half mirror, 23 is a light source,
24 is an azimuth meter, 25 is a tachometer, and 26 is an inclinometer.

The main body device 2 shown in FIG. 1 includes an input image control unit 32, a monitor CRT 33, a data processing device (computer) 34, a magnetic tape 35 and a floppy disk 36, which will be described later with reference to FIG.
A storage device such as a magnetic disk 38, a printer 37, and the like are appropriately incorporated. Image input device (scanner) 1
Captures an image of the wall surface while moving up and down in the borehole, and is connected to a main body device 2 shown in FIG. 2 to be described later and image data is transmitted to the main body device 2. The winch 3 lifts and lowers the image input device 1. When the image input device 1 captures an image of a wall surface and the image data is sent to the main body device 2, the process described below is performed and the crack information is extracted. FIG. 2 shows a specific configuration example of the image input device 1.

In FIG. 2, the image input device (scanner) is mounted on the sonde 12 and moves up and down in the borehole 11. An optical head 17 including a direction indicator 14 and a lens 15 and a mirror 16 is connected to the turning motor 13 on the sonde 12. Further, through the half mirror 20, a light source 23 for sending a light beam to the optical head 17, a lens 22 for forming the light beam, a slit 21, and a slit 38 for detecting a reflected beam from the optical head 17. A photoelectric converter 19 is provided. With such a configuration, the light from the light source 23 is made into a beam shape by the lens 22 and the slit 21, and is applied to the inner wall of the borehole 11 through the half mirror 20, the mirror 16 and the lens 15. Then, the intensity of the reflected beam is measured by the photoelectric converter 19 through the lens 13, the mirror 16, the half mirror 20, and the slit 18. Therefore, the turning motor
When the sonde 12 is lowered while rotating the optical head 17 by means of 13, the inner wall scan u of the borehole 11 is performed as shown in FIG. 3, and an electric signal corresponding to the intensity of the reflected beam is obtained from the photoelectric converter 19. Will be done.

In addition to the above scanner components, the sonde 12 also includes an azimuth meter 24 and an inclinometer as hole bending measurement means.
26. A tachometer 25 is provided as a means for measuring the orientation of the scanner head. The azimuth meter 24 is rotatable about first fulcrums A and A'which are rotatable about a line l that coincides with the axial direction of the sonde 12 as shown by a dotted line and a line m orthogonal to the line l. It is attached to the sonde 12 at the fulcrums A and A'through the second fulcrums Q and Q ', and the measurement unit is supported in a state that does not always change in the vertical direction from the ground. For example, it incorporates a magnet and measures the tilt direction angle of the sonde 12. Similarly, the inclinometer 26 has fulcrums R and R'rotatable about the line 1 and at the points B and B '.
It is attached to 12, and the measuring unit is adapted to rotate around the line 1 in accordance with the inclination of the sonde 12, and for example, incorporates a weight and measures the inclination angle of the sonde 12. Further, the tachometer 25 is provided at the position of the mounting fulcrum A of the compass 24,
Measure the reference direction E of the sonde 12.

In addition, in the three-dimensional coordinate space consisting of x, y, and z shown in FIG.
Assuming that the y-axis direction is the east-west direction and the z-axis direction is the gravity direction of the earth, the azimuth angle θ represents the azimuth from the north, and the inclination angle φ represents the inclination from the horizontal plane. In the sonde 12 shown in FIG. The azimuth angle θ shown in FIG. 4 is obtained from the tilt direction angle indicated by the azimuth meter 24, and the tilt angle φ shown in FIG. 4 is obtained from the tilt angle indicated by the inclinometer 26.

Therefore, it is now assumed that the reference point D shown in FIG. 2 is aligned with the north azimuth and is set as the reference azimuth, and the azimuth θ and the inclination Φ are 0 in the state of the azimuth meter 24 and the inclinometer 26 shown in FIG. If it is defined, for example, from the state shown in FIG.
Is inclined by the angle α toward the north azimuth, the azimuth angle θ is 0, the inclination angle φ is α, and the rotation angle δ is 0. However, when the borehole 11 is tilted toward the west direction by the angle α, the azimuth meter 24 and the inclinometer 26 rotate 90 ° counterclockwise about the line 1 as an axis. Therefore, the azimuth angle θ is -90
The inclination angle φ becomes α, and the rotation angle δ measured by the tachometer 25 becomes 90 °. Further, when the sonde 12 is rotated (twisted) 90 degrees in the west direction, the azimuth angle θ and the inclination angle φ do not change, but only the rotation angle δ measured by the tachometer 25 becomes 0 °. change.

That is, the borehole 11 is made by the azimuth meter 24 and the inclinometer 26.
Is measured, and the orientation of the sonde 12 is measured by the tachometer 25. When measuring with a scanner, the optical head 17 (scanner head) is
The amount of rotation from the reference position E set in the
You can find out which direction you are facing with the output of 14).
The tachometer 24 measures the orientation of the position E, which is the reference of the sonde 12, in order to determine the orientation of the optical head 17 due to the twist. That is, as described above, the azimuth of the reference position E of the sonde 12 can be obtained by adding the rotation angle δ measured by the tachometer 25 to the azimuth angle θ measured by the azimuth meter 24. . On the other hand, the direction indicator 14 of the scanner unit measures the direction in which the optical head 17 (scanner head) is facing from the reference position E of the sonde 12, and therefore the measured value of the optical head 17 is used. By correcting the orientation, the photoelectric converter 19
The observation position of the scan data obtained from can be obtained. The observation position of this scan data can be calculated with an accurate value by using a predetermined calculation formula based on the position coordinate of the rotation center of the optical head 17, its direction, the borehole diameter, and the inclination of the borehole.

FIG. 5 is a diagram showing a configuration of one embodiment of a data processing unit in the automatic borehole crack measuring device of the present invention, and FIG. 6 is a diagram showing a specific functional configuration example of the image data processing device. In the figure, 31 is an imaging unit, 32 is an input image control unit, and 33 is a CR.
T, 34 are data processing devices, 35 is a magnetic tape, 36 is a floppy disk, 37 is a printer, 38 is a magnetic disk, 41 is a binarization processing unit, 42 is a thinning processing unit, 43 is a vectorization processing unit, 44 Is a crack width detection unit, 45 is a vector length / width correction unit,
Reference numeral 46 indicates a crack image data output unit.

In FIG. 5, the image pickup unit 31 is, for example, a television camera or the like that takes an image of a crack in a borehole in place of human eyes. The input image control unit 32 controls the image pickup unit 31 and the CRT 33 for monitoring in order to capture the image obtained by the image pickup unit 31 into the data processing device 34 and display it on the CRT 33. Although not shown, the position movement for imaging is performed by a position movement device according to the shape of the survey target, and image position data information is input from the position movement device. In order to assist the normal operation of the position moving device and the image pickup unit 31, one operator may be arranged. The data processing device 34 is configured by a personal computer or a dedicated processor, and when image data is input from the imaging unit 31 through the input image control unit 32, cracks such as a position, a direction, and a width of the crack are generated from the image data. It is for extracting information. The external storage device that stores both the crack information and the image position data extracted by the data processing device 34 is a magnetic tape.
35, the floppy disk 36, and the magnetic disk 38, and the printer 37 prints out. The crack information and the image position data information may be transmitted to a large-scale computer by using a dedicated line or a telephone line (not shown).

Next, the crack measurement by the automatic crack-measuring device for the borehole shown in FIG. 5 will be described. First, the image information of the subject is captured as a digital image signal by the imaging unit 31 and the input image control unit 32, the captured image is visually confirmed by the CRT 33, and the digital image signal is input to the data processing device 34.

In the data processing device 34, a certain threshold value is set for each pixel of the image data converted into a digital signal and binarized, and then thinning is performed to obtain the center line of the crack. Then, by vectorizing by line tracing, the position and direction of the crack,
Extract crack information such as width. The data obtained by such image processing is recorded in a storage device or transmitted to a large-sized computer using a dedicated line or a telephone line. Then, the whole image is constructed from the recorded or transmitted data and compared with the design information to perform crack analysis.

Next, an example of image data processing by the data processing device 34 will be described with reference to FIG. When image data is input to the data processing device, first, the binarization processing unit 41 outputs 25
The image data digitized to the density of 6 gradations (0 to 255) is divided into two categories with a certain threshold value "1" (black) "0".
Classify as (white).

Then, in order to obtain the crack center line, the thinning processing unit
At 42, the removable points are identified while maintaining the end point storage conditions and the number of connections, and the final points are thinned into a series of 8 continuous points. In this process, isolated points (noise) such as non-linear stains are removed. In addition, such thinning processing is
Although various methods are already known, the present invention is not limited to the specific contents of the thinning process, and it goes without saying that a conventional method may be appropriately selected and applied.

After that, the vectorization processing unit 43 detects the bifurcations and the end points while line tracing (line tracing) the central portion of the thinned crack, and obtains the end point where the virtual vector falls within n pixels from the trace line. The coordinates of the starting point (X1, Y1) in the center of the crack
And a vector group (polygonal line) by the coordinates (X2, Y2) of the end point. As a result, it is possible to obtain direction information that can be understood by a machine (computer) or a human being in a crack image having no direction information as a pattern. Note that needle-shaped noise can be further removed by removing the short vector having no connecting point.

When the vector data is obtained, the crack width detection unit 44 finds the crack width W by collating the vector data with the input image (raw data). The crack width can be detected by taking the differential of the input image with respect to the direction perpendicular to each vector and comparing the value with a threshold value.

The vector length / width correction unit 45 compares the vectors,
Correlation with the raw data is used to correct the missing parts in the binarization stage, and the cut vectors are spliced together. For example, the value of the raw data on the extension line of the vector in the middle of the cut vector is traced to join the cut vectors.

The crack image data output unit 46 draws a line from the vector data, converts it into a crack image, and outputs it.

7 to 13 are diagrams showing examples of image data obtained in the automatic borehole crack measuring device. FIG. 7 is a view showing an example of an input image (raw data), and a developed image is taken by inserting a scanner into the borehole. FIG. 8 is a diagram showing an output example of a crack image based on vector data obtained by processing the input image shown in FIG. FIG. 9 is a diagram showing a method for obtaining the direction (strike / tilt) of a crack from a developed image. FIG. 10 is a diagram showing an output example of a crack data list based on the analysis result, FIG. 11 is a diagram showing a display example in which the analysis result in the predominant direction of the crack is graphed, and FIG. 12 is a statistical processing of the crack width. It is a figure which shows the example of a display made into a graph, and is an example of the number of data 119, average 9, and standard deviation 11. FIG. 13 is a diagram showing a display example in which the correlation between the width of the crack and the depth from the surface is graphed.

The statistical processing and the display so far have input the data of the enormous survey result into the computer again and calculate and plot the data, but according to the crack automatic measuring device for the borehole of the present invention,
The data obtained from the image can be electronically processed as it is and displayed immediately as an easy-to-understand graph.

The present invention can be modified in various ways and is not limited to the above-mentioned embodiments. For example, although the present invention is applied to the measurement of cracks in boreholes in the above-mentioned embodiments, it is needless to say that the present invention can be similarly applied to the measurement of cracks in pipes and other structures.

〔The invention's effect〕

As is clear from the above description, according to the present invention, since the image of the portion to be investigated is obtained while moving the image input device up and down in the borehole, unlike the photograph by the camera, it is possible to perform the depth direction without interruption. A continuous image is obtained. Since the crack information is extracted by performing a predetermined process from such an image by image data processing, a constant crack distribution / width measurement accuracy can be ensured and there is no difference between investigators. Moreover, only one operator is required, which can reduce the research labor and the research period. In addition, a general recording medium such as a magnetic tape can be used for data storage, and the storage capacity can be secured as necessary in a unified manner.

Even in the borehole survey, the inclination angle, inclination angle,
By detecting the length and calculating the position of each point, it is possible to know the exact observation position and depth even if the borehole is bent. Also, since the orientation of the scanner head is calculated by detecting the rotation of the sonde in the borehole, the observation position and depth of scan data can be accurately grasped.
Furthermore, even if it is an inclined hole, it is possible to perform observation with a horizontal image according to the observation position of each scan data, and it is also possible to continuously observe oblique faults in the inclined hole based on accurate positions.

[Brief description of drawings]

FIG. 1 is a diagram showing a state of use of an automatic crack measuring device for a borehole according to the present invention, FIG. 2 is a diagram showing a concrete configuration example of an image input device, and FIG. 3 is a hole scanned by a light beam. FIG. 4 is a diagram showing a locus of a wall development surface, FIG. 4 is a diagram for explaining detection angles of an azimuth meter and an inclinometer, and FIG. 5 is a configuration of one embodiment of a data processing unit in an automatic crack measuring device for a borehole of the present invention. FIG. 6, FIG. 6 is a diagram showing a specific functional configuration example of the image data processing device, and FIGS. 7 to 13 are diagrams showing examples of image data obtained in the crack automatic measurement device for boreholes. FIG. 7 is a diagram showing an example of an input image (raw data),
FIG. 8 is a diagram showing an output example of a crack image based on vector data obtained by processing the input image shown in FIG. 7, and FIG. 9 is a method for obtaining the direction (strike / tilt) of the crack from the developed image. Fig. 10, Fig. 10 is a diagram showing an output example of a crack data list by analysis results, Fig. 11 is a diagram showing a display example in which the analysis results of the predominant direction of cracks are graphed, and Fig. 12 shows the width of cracks. FIG. 13 is a diagram showing a display example in which statistical processing is performed, and FIG. 13 is a diagram showing a display example in which a correlation between a crack width and a depth from the surface is plotted. 1 ... Image input device (scanner, imaging unit), 2 ... Main device, 3 ... Winch for winding up the image input device, 11 ... Borehole, 12 ... Sonde, 13 ... Rotation motor, 14 ... … Director, 15 and 22 …… Lens, 16 …… Mirror, 17 …… Optical head, 18 and 21 …… Slit, 19 …… Photoelectric converter, 20 …… Half mirror, 23 …… Light source, 24… …
Compass, 25 ... Tachometer, 26 ... Inclinometer, 31 ... Imaging unit,
32: input image control unit, 33: CRT, 34: data processing device, 35: magnetic tape, 36: floppy disk,
37 ... Printer, 38 ... Magnetic disk, 41 ... Binarization processing section, 42 ... Thin line processing section, 43 ... Vectorization processing section,
44: Crack width detection unit, 45: Vector length / width correction unit,
46: Crack image data output section.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Koji Nagata 2-16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Hitoshi Sakurai 2-1-1-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (56) Reference JP 61-186693 (JP, A) JP 61-176797 (JP, A) JP 61-186694 (JP, A) JP 61-126292 ( JP, A) Actual development Sho 62-190782 (JP, U)

Claims (5)

[Claims] 1. An automatic crack hole measuring device for measuring a crack by processing image data obtained by picking up an image of a wall surface of a bore hole, which is built in a sonde that moves up and down along the wall surface of the bore hole. A scanner for obtaining image data, a binarizing means for setting a threshold value to binarize the image data, a thinning processing means for obtaining a center line of a pixel group in which the binarized data are connected, the center line as a vector An automatic crack measuring device for a borehole, comprising: a vectorizing means for converting the information into cracks; and a crack detecting means for detecting crack information from the vectorized center line and image data. 2. The automatic borehole crack measuring device according to claim 1, wherein the thinning processing means obtains a centerline of the connected pixel groups and removes non-linear isolated points. 3. The automatic borehole crack measuring device according to claim 1, wherein the vectorizing means vectorizes the center line and removes the short vector. 4. A crack hole automatic measuring device according to claim 1, wherein the crack detecting means obtains a crack width by differentiating the image data with respect to a direction perpendicular to each vector. . 5. The sonde has a length of cable to be hung from the ground, an inclination direction of the sonde, an inclination angle of the sonde,
And detecting the rotation direction of the sonde, calculating the position of the sonde, the inclination of the sonde, and the direction in which the scanner head incorporated in the sonde is facing, and observing the hole wall. The automatic device for measuring cracks in a borehole according to item 1.