KR102507543B1 - Measurement system of pile penetration and rebound - Google Patents

Abstract

The present invention captures images of a file marker and a reference marker attached to one side of a file with a camera, and analyzes the images of the file marker and the reference marker captured by the data processing unit to directly calculate the relative displacement on three-dimensional coordinates, thereby generating a separate acceleration It is about a pile penetration and rebound measurement system that can accurately measure the penetration and rebound of piles without a sensor.
The present invention includes one file marker attached to one side of a file to be measured by displaying a figure that is a 2D image; a fiducial marker provided at an adjacent position of the measurement object file; a camera that simultaneously captures a video of the file marker and the reference marker; File markers and fiducial markers are recognized from images for each unit time extracted from video data taken by the camera, and 2D images of figures displayed on the file markers and fiducial markers are analyzed to determine the size and shape of the figures displayed on the file markers and fiducial markers. Data that calculates the shape change of 2D images according to the change in the warp direction per unit time and calculates the relative displacement of the pile marker with respect to the reference marker on the 3D coordinates, converting it into coordinates in the 3D space to measure the amount of penetration and rebound of the pile processing unit; and a display unit outputting the penetration amount and rebound amount of the file calculated by the data processing unit. It is characterized by consisting of.

Description

Pile penetration and rebound measurement system {Measurement system of pile penetration and rebound}

The present invention captures images of a file marker and a reference marker attached to one side of a file with a camera, analyzes the images of the file marker and the reference marker captured by the data processing unit, and directly calculates the relative displacement on three-dimensional coordinates. It is about a pile penetration and rebound measurement system that can accurately measure the penetration and rebound of piles without a sensor.

When the upper ground is soft ground such as weathered soil, a pile foundation, which is a deep foundation, is mainly used because there is a risk of settlement if a direct foundation is used.

Pile foundation is a structurally stable foundation construction method in which the pile penetrates through the upper soft layer to the lower hard layer to support the load of the structure.

In this way, pile load tests such as dynamic load tests or static load tests are conducted to determine the size of the load that can be supported in the maximum load or allowable settlement range for piles embedded in the ground.

Among them, the dynamic load test is the most commonly applied test method to confirm bearing capacity. The dynamic load test manages the amount of penetration by measuring the displacement that occurs in the pile during driving, such as the amount of penetration and rebound.

In the past, in order to measure the amount of penetration and rebound during pile driving, a recording paper such as graph paper was attached to the pile, a guide was installed in front of the recording paper, a pen supported by the guide was closely attached to the recording paper, and then the pile was driven vertically. The displacement was marked on the recording paper.

Accordingly, the operator directly moves the pen horizontally for each hit of the file to be recorded, and the penetration amount and rebound dynamic bearing capacity were calculated as the average value of the last 10 or more hits.

However, these conventional methods are inconvenient in that accuracy is low and the recording paper must be analyzed separately. In addition, since the operator has to measure in close proximity to the test object file, there is a concern about worker safety accidents.

In order to solve the problems of the conventional measurement method, a shooting target is attached to the front of the pile and the shooting target is photographed with a camera to measure the displacement of the shooting target, and an acceleration sensor is attached to the shooting target to measure the rebound amount after driving the pile. was developed (Registration Patent No. 10-2200824).

In the registration technique, the acceleration sensor measures the amount of rebound by measuring the amplitude of the vibration caused by the driving of the driving pile. And the measured acceleration value is converted into displacement through FFT (Fast Fourier Transform) process.

In this conversion process, it is necessary to go through two integration processes, but due to the noise of the sensor itself, it is inevitable that bias occurs due to accumulated errors during integration. In addition, since a complicated post-processing process is required to correct this bias, there is a limit to accurate measurement of penetration and rebound.

In addition, the camera measures the vertical displacement from the photographed image of the photographing target, and the camera must maintain a constant distance from the photographing target. However, the shaking of the camera is very severe due to ground vibration during pile driving, making it difficult to trust the measured value.

In order to solve the above problems, the present invention analyzes the pile marker image without a separate acceleration sensor and directly calculates the three-dimensional relative displacement of the pile, thereby accurately measuring the pile penetration and rebound amount. We want to provide a volume measurement system.

The present invention according to a preferred embodiment is for measuring the amount of penetration and the amount of rebound when driving a pile embedded in the ground, and a 2D image of a figure is displayed and attached to one side of the pile to be measured. One pile marker; a fiducial marker provided at an adjacent position of the measurement object file; a camera that simultaneously captures a video of the file marker and the reference marker; File markers and fiducial markers are recognized from images for each unit time extracted from video data taken by the camera, and 2D images of figures displayed on the file markers and fiducial markers are analyzed to determine the size and shape of the figures displayed on the file markers and fiducial markers. Data that calculates the shape change of 2D images according to the change in warp direction per unit time and calculates the relative displacement of the pile marker with respect to the reference marker in 3D coordinates, converting it into coordinates in 3D space to measure the amount of penetration and rebound of the pile processing unit; and a display unit outputting the penetration amount and rebound amount of the file calculated by the data processing unit. It provides a pile penetration and rebound amount measuring system, characterized in that consisting of.

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The present invention according to another preferred embodiment provides a pile penetration amount and rebound amount measuring system, characterized in that the front of the pile is provided with a holder for fixing the reference marker.

The present invention according to another preferred embodiment provides a pile penetration amount and rebound amount measuring system, characterized in that the camera is installed in the holder.

According to the present invention, images of the pile marker and the reference marker attached to one side of the pile are taken with a camera when the pile is driven into the ground, and the images of the pile marker and the reference marker taken by the data processing unit are analyzed to determine the relative displacement in 3D coordinates. It is possible to provide a pile penetration and rebound measurement system capable of measuring the penetration and rebound of the pile by calculating with .

Therefore, the 3D relative displacement of the pile can be directly calculated by analyzing the pile marker and fiducial marker images without a separate acceleration sensor, and the pile penetration amount and rebound amount can be accurately measured.

1 is a diagram showing a system for measuring pile penetration and rebound amount according to the present invention.
2 is a diagram showing a file marker image;
3 is a diagram showing an image of a file marker recognized by a data processing unit in three-dimensional coordinates;
Fig. 4 shows an embodiment with pile markers and fiducial markers;
5 is a diagram showing a relative displacement measurement result by a reference marker and a pile marker;
Fig. 6 is a diagram showing the concept of relative displacement measurement by a reference marker and a pile marker;
7 is a view showing an embodiment in which a fiducial marker and a camera mounting bracket are installed.

Hereinafter, the present invention will be described in detail according to the accompanying drawings and preferred embodiments.

1 is a diagram showing a system for measuring the amount of penetration and rebound of a file according to the present invention, FIG. 2 is a diagram showing an image of a file marker, and FIG. 3 is a diagram showing an image of a file marker recognized by a data processing unit in three-dimensional coordinates. .

As shown in FIG. 1, etc., the system for measuring the amount of penetration and rebound of piles of the present invention is for measuring the amount of penetration and rebound when driving a pile (1) embedded in the ground. One file marker (2) attached to one side of (1); a camera 4 for taking a video of the file marker 2; The file marker 2 is recognized from the image for each unit time extracted from the video data taken by the camera 4, and the 2D image of the figure displayed on the file marker 2 is analyzed to obtain the figure displayed on the file marker 2 By calculating the shape change of 2D images according to the change in the size and warp direction per unit time, and calculating the relative displacement of the file marker (2) on the 3D coordinates, converting it into coordinates in 3D space, penetrating amount and rebound of the pile (1) a data processing unit 5 for measuring quantity; and a display unit 6 outputting the penetration amount and rebound amount of the pile 1 calculated from the data processing unit 5; It is characterized by consisting of.

The present invention analyzes the image of the pile marker 2 without a separate acceleration sensor and directly calculates the three-dimensional relative displacement of the pile 1, thereby accurately measuring the penetration amount and rebound amount of the pile 1. It is to provide a system for measuring the amount and rebound amount.

The present invention is to measure the penetration amount and rebound amount of the pile (1) by driving the pile (1) embedded in the ground.

The present invention is composed of a file marker 2, a camera 4, a data processing unit 5 and a display unit 6.

The pile marker 2 is attached to one side of the pile 1 to be measured.

A figure is displayed on the file marker 2.

The camera 4 photographs the file marker 2 .

The camera 4 may be provided at a position spaced apart from the file 1 by a predetermined distance in front of the file marker 2 attached to the file 1.

The camera 4 may be a general digital camera 4 as well as a smart phone or the like.

The camera 4 can take a video of the pile marker 2 when the pile 1 is driven.

The data processing unit 5 analyzes the image of the file marker 2 captured by the camera 4 to obtain a three-dimensional image of the file marker 2 according to changes in the size and twist direction of the figure displayed on the file marker 2. The penetration amount and rebound amount of the pile 1 are measured by calculating the relative displacement on the coordinates.

That is, the data processor 5 recognizes the file marker 2 from the image for each unit time extracted from video data captured by the camera 4, and analyzes changes in the position, size and shape of the file marker 2. do.

The data processing unit 5 calculates the relative displacement of the file marker 2 on three-dimensional coordinates from this analysis data.

In other words, the pile marker 2 itself is a 2D image, but the two-dimensional shape of the image captured by the camera 4 according to the position change of the pile 1 when the pile 1 is driven is the original 2D image of the pile marker 2. There is a difference with the dimensional shape. The data processing unit 5 converts these 2D images into coordinates in a 3D space by calculating shape changes.

For this, the file marker 2 may use an ArUco marker.

The ArUco marker consists of an n×n 2-dimensional bit pattern and a black border area surrounding it (FIG. 2).

The black border area of the ArUco markers allows quick recognition of the markers.

The two-dimensional bit pattern inside the black frame expresses the unique ID of the marker as a combination of white cells and black cells.

Since each cell of the ArUco marker is a square with right angle corners, 3D coordinates can be set by measuring the length ratio of each side of the cell and the warp (angle between each side) of the cell (FIG. 3).

Accordingly, vibration or movement in the Z-axis direction as well as the X and Y axes, which are planes perpendicular to the direction of the camera 4, can be recognized, so that more accurate displacement can be calculated.

In addition, the pile 1 and the camera 4 do not need to be strictly level with each other, making it easy to set the measuring equipment.

The display unit 6 outputs the amount of penetration and rebound of the file 1 calculated from the data processing unit 5.

The display unit 6 may display the relative displacement of the file 1 calculated by the data processing unit 5 by providing it as a numerical value or a graph.

From this, the operator can check the amount of penetration and rebound of the pile (1) when driving the pile (1).

4 is a view showing an embodiment provided with a pile marker and a reference marker, FIG. 5 is a view showing a relative displacement measurement result by the reference marker and the pile marker, and FIG. 6 is a relative displacement by the reference marker and the pile marker. It is a diagram illustrating the measurement concept.

As shown in FIGS. 4 to 6, a fiducial marker 3 is further provided at an adjacent position of the measurement object file 1, and the camera 4 uses the file marker 2 and the fiducial marker 3. Simultaneously, the data processing unit 5 may be configured to calculate the three-dimensional relative coordinates of the pile marker 2 with respect to the reference marker 3 to measure the amount of penetration and rebound of the pile 1.

The reference marker 3 may be installed adjacent to the pile 1 to be measured in order to accurately measure the amount of penetration and rebound of the pile 1 regardless of the vibration or movement of the camera 4.

The installation position of the fiducial marker 3 may be any position as long as it is included in the screen of the camera 4.

The fiducial marker 3 may also use an ArUco marker.

5 shows the relative distance between the reference marker 3 and the pile marker 2 on the 3D coordinates and the vertical displacement value of the pile marker 2 calculated therefrom.

The data processor 5 recognizes the file marker 2 and the reference marker 3 from the image captured by the camera 4, and sets the origin and 3D axis of each marker.

In FIG. 5, the red line represents the X-axis, the green line represents the Y-axis, and the blue line represents the Z-axis.

The X-axis and Y-axis coincide with the horizontal and vertical sides of the square cell in the ArUco marker, and the Z-axis is set based on the case where the shape of the cell in the image is a square with each corner at right angles.

Referring to FIG. 6, the concept of measuring the relative displacement by the reference marker 3 and the pile marker 2 will be described as follows.

Relative vectors seen from the viewpoint of the file marker 2 from the camera 4 and the reference marker 3 from the camera 4 become the file marker vector (a) and the reference marker vector (b), respectively.

The double file marker vector (a) is reversed from the file marker (2) to the relative vector viewed from the camera (4) point of view (-a).

For view reversal, rotation matrix transformation (Rodrigues) and matrix multiplication are utilized.

Then, when the relative vector from the viewpoint of the camera 4 in the file marker 2 and the relative vector from the viewpoint of the reference marker 3 from the camera 4 are synthesized, the relative vector from the viewpoint of the file marker 2 to the reference marker 3 (c) can be obtained.

Therefore, a relative vector independent of the state of the camera 4 is calculated. In addition, if the relative vector at the point of view of the reference marker (3) is set as the origin in the pile marker (2), and the movement displacement is continuously tracked, the amount of penetration of the pile (1) and the The amount of rebound can be measured.

Accordingly, an accurate measurement value can be obtained even if a worker directly holds the camera 4 in his hand and takes a picture without fixing the camera 4 to a separate support member such as a tripod. In this case, image stabilization of the camera 4 is also not required.

As shown in Figure 4, the front of the pile (1) may be provided with a holder (7) to which the reference marker (3) is fixed.

The reference marker 3 is a reference point for measuring the relative displacement of the pile marker 2, and must be installed separately from the pile 1 on the upper part of the ground.

To this end, a holder 7 may be installed on the ground, and the reference marker 3 may be fixed to the holder 7.

The holder 7 may be a tripod or a separate frame.

7 is a view showing an embodiment in which a fiducial marker and a camera are installed.

As shown in FIG. 7 , the camera 4 may be installed in the holder 7 .

In the case of using the reference marker 3 and the pile marker 2, even if movement or vibration of the camera 4 occurs, the measurement values of the penetration amount and rebound amount of the pile marker 2 are not affected, so that the camera 4 and the reference It is not necessary to fix the relative position of the marker 3. However, the camera 4 may be installed at the same time in the holder 7 where the reference marker 3 is installed to promote the convenience of the measurement work and to ensure the safety of the operator when driving the pile 1.

Accordingly, when measuring the penetration amount and the rebound amount for the plurality of piles 1, it is possible to set quickly by moving only the reference marker 3 and the holder 7 to which the camera 4 is mounted.

In addition, the reference marker 3 and the file marker 2 should be simultaneously photographed with the camera 4, but when the operator directly holds the camera 4 and takes the picture, the reference marker 3 is not captured by the camera 4 due to operator error. Sometimes it goes off screen.

Accordingly, when both the fiducial marker 3 and the camera 4 are mounted on the holder 7, the relative positions of the fiducial marker 3 and the camera 4 are fixed, so that the fiducial marker 3 always follows the camera 4. It can be set to be positioned within the screen. Therefore, the fiducial marker 3 is not missing from the screen.

The holder 7 is a main frame 71 mounted on the ground, a camera holder 72 provided on the upper part of the main frame 71 to which the camera 4 is mounted, and the main frame 71 It may be composed of a fiducial marker holder 73 protruding forward and mounted so that the fiducial marker 3 is located in front of the camera 4 (FIG. 7).

1: File
2: file marker
3: reference marker
4: camera
5: data processing unit
6: display unit
7: Cradle
71: mainframe
72: camera holder
73: reference marker holder

Claims (4)

It is for measuring the amount of penetration and rebound when driving a pile (1) embedded in the ground.
One file marker (2) attached to one side of the file (1) to be measured by displaying a figure that is a 2D image;
A reference marker (3) provided at an adjacent position of the measurement target file (1);
a camera 4 for simultaneously taking a video of the file marker 2 and the reference marker 3;
The file marker 2 and the fiducial marker 3 are recognized from the image for each unit time extracted from the video data captured by the camera 4, and the 2D of the figure displayed on the file marker 2 and fiducial marker 3 is obtained. By analyzing the image and calculating the shape change of 2D images according to the change in the size and warp direction of the figures displayed on the file marker 2 and the fiducial marker 3 per unit time, the A data processing unit 5 for measuring the amount of penetration and rebound of the pile 1 by converting the relative displacement on 3D coordinates into coordinates in 3D space; and
a display unit 6 for outputting the penetration amount and rebound amount of the pile 1 calculated from the data processing unit 5; Pile penetration and rebound measurement system, characterized in that consisting of.
delete In paragraph 1,
Pile penetration amount and rebound amount measurement system, characterized in that the front of the pile (1) is provided with a holder (7) to which the reference marker (3) is fixed.
In paragraph 3,
The camera (4) is a pile penetration amount and rebound amount measurement system, characterized in that installed in the holder (7).

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