Method for checking the condition of a vertical shaft

Abstract

The present invention aims to provide a groundbreaking method for checking the condition of a shaft, unlike anything seen before. [Solution] A rigid, elongated body 1, with markings 1a provided at equal intervals, is suspended from a specific XYZ coordinate position A1 at the upper opening of the shaft 50 into the shaft 50. A lightweight, wide measuring tape 5, with length scales 5a on its surface, is also suspended into the shaft 50. The shaft 50 is photographed using an appropriate photographic means to create an image of the shaft 50 that includes the markings 1a of the elongated body 1 and the length scales 5a of the measuring tape 5. A three-dimensional point cloud 30 is created from this image to confirm changes in the state of the shaft 50.

Description

Technical Field

[0001] The present invention relates to a method for confirming the state of a shaft.

Background Art

[0002] Conventionally, when confirming state changes such as damage and displacement on the inner wall surface of a shaft structure surrounded by wall surfaces on all sides, for example, a tunnel (hereinafter referred to as "conventional example"), confirmation is performed using a three-dimensional point cloud generated by a three-dimensional point cloud generation device disclosed in Patent Document 1.

[0003] This conventional example includes a photographing unit that photographs the inner wall surface of the tunnel and a three-dimensional point cloud generation unit that generates a three-dimensional point cloud based on the image photographed by this photographing unit. The photographing unit is moved inside the tunnel to photograph the inner wall surface, and a three-dimensional point cloud is generated by the three-dimensional point cloud generation unit based on the image photographed by this photographing unit. By assigning coordinates to the image photographed by the photographing unit, a more accurate three-dimensional point cloud can be obtained.

[0004] Using this conventional example, the three-dimensional point clouds obtained at different times are compared and studied to confirm state changes such as damage and displacement on the inner wall surface of the tunnel.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, in addition to the tunnels mentioned above, there are also vertical shafts used for water collection, which are enclosed structures with walls and are installed in areas prone to landslides. There is a demand to use 3D point clouds to check changes in the state of these vertical shafts as well. To generate a 3D point cloud for these vertical shafts, a camera unit is suspended inside the shaft and lowered to photograph the inner wall surface. A 3D point cloud generation unit then generates a 3D point cloud based on the images taken by this camera unit.

[0007] Furthermore, in order to obtain the coordinates (XYZ coordinates) inside the shaft in order to create a highly accurate 3D point cloud of the shaft, some of these shafts can reach depths of up to 100m. While the coordinates near the upper opening of the shaft can be easily obtained using GPS surveying, GPS measurement is not possible inside the shaft, making it difficult to easily obtain highly accurate coordinates (Z coordinates) in the depth direction.

[0008] Therefore, as a simple method for obtaining the Z-coordinate in the depth direction within a shaft, a cloth measuring tape with a scale is suspended (a weight is attached to the lower end of the measuring tape), and the Z-coordinate can be obtained by visually observing the scale in the image. However, in reality, when this measuring tape is suspended, it may twist or stretch more than expected, or it may hit an obstacle (such as the stairs used for ascending and descending within the shaft) and not hang vertically, so there are cases where the Z-coordinate is determined without realizing that the scale is displaying an inaccurate depth.

[0009] This invention solves the aforementioned problems and provides a groundbreaking method for checking the condition of a shaft, unlike anything seen before. [Means for solving the problem]

[0010] The gist of the present invention will be explained with reference to the attached drawings.

[0011] A method for confirming the state of a shaft 50, which involves using a three-dimensional point cloud 30 created from an image of the shaft 50 and the XYZ coordinates of the shaft 50 to confirm changes in the state of the shaft 50, characterized in that a rigid, elongated body 1, having markings 1a at equal intervals, is suspended from a specific XYZ coordinate position A1 at the upper opening of the shaft 50 into the shaft 50, and a lightweight, wide measuring tape 5, having length scales 5a on its surface, is suspended into the shaft 50, the shaft 50 is photographed using an appropriate photographic means to create an image of the shaft 50 that includes the markings 1a of the elongated body 1 and the length scales 5a of the measuring tape 5, and the three-dimensional point cloud 30 is created from this image to confirm changes in the state of the shaft 50.

[0012] Furthermore, the method for confirming the condition of a shaft according to claim 1 is characterized in that the marker portion 1a is provided on the elongated body 1 at 1m intervals.

[0013] Furthermore, the present invention relates to a method for confirming the condition of a shaft according to either claim 1 or 2, characterized in that different colored display sections 1' are alternately arranged on the surface of the elongated body 1 at 1m intervals, and the boundaries between the colored display sections 1' are configured as the marker section 1a.

[0014] Furthermore, the method for confirming the condition of a shaft according to either claim 1 or 2 is characterized in that the elongated body 1 is suspended into the shaft 50 from specific XYZ coordinate positions A1 and A2 at multiple positions on the same plane at the upper opening of the shaft 50, the measuring tape 5 is suspended into the shaft 50, and the shaft 50 is photographed using an appropriate photographic means to create an image of the inside of the shaft 50 that includes the markings 1a of each elongated body 1 and the length scale 5a of the measuring tape 5.

[0015] Also, in the vertical shaft state confirmation method according to claim 3, at a plurality of positions on the same plane at the upper opening of the vertical shaft 50, specifically at positions A1 and A2 of specific XYZ coordinates, the long body 1 is respectively suspended into the vertical shaft 50, and the measurer 5 is suspended into the vertical shaft 50. The vertical shaft 50 is photographed by an appropriate photographing means, and an image inside the vertical shaft 50 is created as an image including the mark portions 1a of each of the long bodies 1 and the length scale portion 5a of the measurer 5. It relates to a vertical shaft state confirmation method characterized by this.

Effect of the Invention

[0016] Since the present invention is configured as described above, a highly accurate three-dimensional point cloud of the vertical shaft can be obtained simply and reliably, and thus the state change of the vertical shaft can be confirmed well. It becomes an epoch-making vertical shaft state confirmation method not seen before.

Brief Explanation of Drawings

[0017] [Figure 1] It is a front view showing the photographing unit 20 according to this embodiment. [Figure 2] It is a front view showing the long body according to this embodiment. [Figure 3] It is an explanatory view of a state of photographing the inside of the vertical shaft 50 using the photographing unit 20 according to this embodiment. [Figure 4] It is an explanatory view of an image obtained by photographing the inside of the vertical shaft 50 using the photographing unit 20 according to this embodiment. [Figure 5] It is an explanatory view of the three-dimensional point cloud 30 generated by the three-dimensional point cloud generation unit according to this embodiment. [Figure 6] It is an explanatory view of a vertical shaft state confirmation method for confirming the state change of the vertical shaft 50 using the three-dimensional point cloud 30 according to this embodiment.

Modes for Carrying Out the Invention

[0018] Preferred embodiments of the present invention will be briefly described based on the drawings while showing the operation of the present invention.

[0019] In order to check the state change of the shaft 50, a high-precision 3D point cloud 30 is created from the image in the shaft 50 and the XYZ coordinates in the shaft 50.

[0020] Specifically, a rigid long body 1 with marking parts 1a provided at equal pitches is suspended into the shaft 50 from a position A1 of specific XYZ coordinates at the upper opening of the shaft 50, and a measuring tool 5 that is lightweight, wide in width, and has a length scale part 5a on its surface is also suspended into the shaft 50. At this time, the long body 1 is suspended with an arbitrary marking part 1a aligned with the position A1 of the specific XYZ coordinates. On the other hand, the measuring tool 5 is suspended with an arbitrary length scale part 5a (for example, a length scale part 5a with a clear numerical value in units of 1 meter) aligned with a position B of XYZ coordinates where the Z coordinate is the same as that of the position A1.

[0021] This long body 1 is made of a rigid material and can be suspended vertically without twisting or stretching. Also, the marking parts 1a provided on the long body 1 are provided at equal pitches. Therefore, for example, by looking at the taken image, the state of the measuring tool 5 can be confirmed as normal or abnormal by comparing it with this long body 1. That is, if the marking part 1a of the long body 1 and the length scale part 5a of the measuring tool 5 are clearly misaligned, the abnormality of the measuring tool 5 can be confirmed.

[0022] The inside of the shaft 50 is photographed by appropriate photographing means, and an image in the shaft 50 is created as an image including the marking part 1a of the long body 1 and the length scale part 5a of the measuring tool 5. By checking the depth distance (Z coordinate) from the position A1 based on the length scale part 5 provided with a large display on the measuring tool 5a that is wider than this long body 1 and clearly shown in the image for an arbitrary marking part 1a of the long body 1 inside the shaft 50, the XYZ coordinates of that position can be obtained. If the long body 1 is made wide and a large length scale part is displayed on this long body 1, the measuring tool 5 becomes unnecessary. However, in reality, if the long body 1 is made wide, the weight becomes extremely large, and the workability deteriorates, which is not practical. Also, if only the long body 1 is used, the width is narrow, so the length scale part is small and cannot be measured. Therefore, by using this long body 1 and the measuring tool 5 together, good workability can be realized.

[0023] A 3D point cloud 30 is created from the image inside the shaft 50 and the XYZ coordinates inside the shaft 50 obtained as described above, and this 3D point cloud 30 is used to check the changes in the state of the shaft 50.

[0024] Therefore, without using specially high-precision and expensive equipment, the coordinates within the shaft 50 can be accurately determined using a simple method, and a high-precision 3D point cloud 30 can be obtained, thus enabling good confirmation of changes in the state of the shaft 50. [Examples]

[0025] Specific embodiments of the present invention will be described with reference to the drawings.

[0026] This embodiment is a method for checking the state of a shaft 50 by using a 3D point cloud 30 created from an image of the shaft 50 and the XYZ coordinates of the shaft 50, wherein the 3D point cloud 30 is created using a 3D point cloud creation device described later.

[0027] Specifically, this 3D point cloud generation device includes a suitable imaging means (imaging unit 20) that mainly photographs the inside of the shaft 50, a 3D point cloud generation unit (not shown) that generates a 3D point cloud 30 based on the images taken by the imaging unit 20, a long body 1, and a measuring tape 5.

[0028] The imaging unit 20, as shown in Figure 1, is a mobile terminal (smartphone) with communication and digital camera functions, and can acquire images using its built-in 3D model creation support function (for example, the 3D model creation support application "PIX4D Catch" / PIX4D is a registered trademark).

[0029] Furthermore, the imaging unit 20 has a built-in LiDAR sensor (Light Detection and Ranging / LiDAR is a registered trademark), and this LiDAR sensor is configured to add information about the distance between the imaging unit 20 and the subject (the inner wall surface of the shaft 50) to the image captured using the 3D model creation support function.

[0030] Therefore, by processing an image containing distance information between the imaging unit 20 and the subject (the inner wall surface of the shaft 50) using the image processing function of the 3D point cloud generation unit described later, a highly accurate 3D point cloud 30 can be created.

[0031] Furthermore, in this embodiment, a lighting unit 22, disclosed in Japanese Patent No. 6596042, is provided on a base body 21 on which a storage unit 21a housing the imaging unit 20 rotates 360 degrees horizontally (driven by a motor). The base body 21, on which the imaging unit 20 and the lighting unit 22 are provided, is suspended into the shaft 50 from the upper opening of the shaft 50 using a suspension device 23 disclosed in Japanese Patent No. 6089069.

[0032] Therefore, the imaging unit 20 can be raised and lowered within the shaft 50 by the suspension device 23, and by rotating horizontally 360 degrees, it can capture images of the entire inside of the shaft 50.

[0033] Furthermore, in this embodiment, an image display device (not shown) is provided that has a communication function that enables the transmission and reception of electronic data with the imaging unit 20, and has an image display monitor that displays images captured by the imaging unit 20 in real time during imaging work inside the shaft 50 by the imaging unit 20.

[0034] The 3D point cloud generation unit is a portable electronic computer (PC) equipped with communication capabilities to send and receive electronic data with the imaging unit 20, and also has a built-in function to create a 3D point cloud 30 from images captured by the imaging unit 20 (for example, the point cloud processing application "PIX4D Matic" / PIX4D is a registered trademark).

[0035] Therefore, multiple images (digital photographic data) of the inside of the shaft 50 transmitted from the imaging unit 50 are received, and a high-precision 3D point cloud 30 is generated from these images using SfM (Structure from Motion) analysis technology.

[0036] As shown in Figure 2, the elongated body 1 is a narrow, strip-shaped body approximately 1 cm wide and 100 m long, made of a suitable hard (metallic) material, and is provided so as to be able to be wound up and stored in the winding device 1b.

[0037] Furthermore, markings 1a are provided at equal intervals on both the front and back surfaces of the elongated body 1.

[0038] In this marker section 1a, different colored display sections 1' are arranged alternately at 1m intervals on the surface of the elongated body 1, and the boundary lines between the colored display sections 1' constitute the marker section 1a. Specifically, a silver base is painted with blue or red, or other easily recognizable colors such as white or yellow, at 1m intervals.

[0039] Similar to Measure 5, which will be described later, length markings (scale lines) are also provided on both the front and back surfaces of the long body 1.

[0040] Furthermore, a weight 1d is provided at the tip of the elongated body 1 (the lower end when hanging).

[0041] As shown in Figure 3, Measure 5 is a wide, strip-shaped body approximately 6 cm wide and 100 m long, formed from a suitable fabric material (a woven fabric that is softer and lighter than the long body 1), and is lighter and wider than the long body 1 mentioned above.

[0042] Furthermore, the front and back surfaces of the measuring tape 5 are provided with length scale sections 5a (scale lines and numbers).

[0043] Furthermore, a weight 5b is provided at the tip of the measuring tape 5 (the lower end when hanging).

[0044] This section describes a method for confirming the state of a shaft 50 by generating a 3D point cloud 30 of the shaft 50 using the 3D point cloud generation device according to this embodiment, which has the above configuration, and then using this 3D point cloud 30 to confirm changes in the state of the shaft 50.

[0045] A long body 1 is suspended from multiple positions on the same plane of the metal mesh cover 51 provided at the upper opening of the shaft 50, specifically at positions A1 and A2 in the XYZ coordinate system, until the weight 1d at its lower end is positioned near the bottom of the shaft 50. At the same time, a measuring tape 5 is suspended from the shaft 50 until the weight 5b at its lower end is positioned near the bottom of the shaft 50. In this case, the long body 1 is suspended with an arbitrary marking portion 1a aligned with positions A1 and A2 in the XYZ coordinate system (an arbitrary mesh hole 51a with a maximum diameter of about 3 cm, and the opening edge of the mesh hole 51a). Meanwhile, the measuring tape 5 is suspended along the inner wall surface of the shaft 50 with an arbitrary length scale portion 5a (for example, a length scale portion 5a that gives a neat value in units of 1 meter) aligned with position B in the XYZ coordinate system (the end of the cover 51), which has the same Z coordinate as positions A1 and A2.

[0046] Each of these elongated bodies 1 is made of a rigid material (metal), does not twist or stretch, and can be hung vertically. Furthermore, the markings 1a on the elongated bodies 1 are spaced at equal intervals. Therefore, by looking at the captured image, it is possible to check whether the measuring tape 5 is normal or abnormal by comparing it with the elongated body 1. In other words, if the markings 1a on the elongated body 1 and the length scale 5a on the measuring tape 5 are clearly misaligned, it can be confirmed that the measuring tape 5 is abnormal.

[0047] The camera unit 20 is lowered by the suspension device 23 and rotated horizontally 360 degrees to photograph the entire inner wall surface of the shaft 50, the elongated object 1 (marker part 1a), and the measuring tape 5 (length scale part 5a) (at this time, the worker is outside the shaft 50 and is checking the situation inside the shaft 50 in real time by looking at the image displayed on the image display monitor of the image display device). Multiple image data captured by this camera unit 20 are transmitted to the 3D point cloud generation unit, and also at the aforementioned positions A1, A2, and B. The X,Y coordinates are obtained by GPS (GNSS) surveying to determine the XYZ coordinates at positions A1 and A2. Then, the depth distance (Z coordinate) from positions A1' and A2' is confirmed based on the length scale 5, which is wider than each of the elongated bodies 1 and has large markings that are clearly visible in the image, at the positions A1' and A2' of arbitrary markers 1a of each elongated body 1 within the shaft 50. The XYZ coordinates of positions A1' and A2' within the shaft 50 are then determined (see Figure 4). Note that the measuring tape 5 is made of cloth (woven fabric) and has a weight 5b at its lower end, so it stretches slightly, but this is an error that can be dealt with based on empirical rules.

[0048] Furthermore, in this embodiment, as described above, two elongated bodies 1 are suspended to determine the XYZ coordinates within the shaft 50, that is, by providing multiple coordinate axes, the orientation of the shaft 50 (3D point cloud 30) can be determined. However, it is also possible to perform this with only one elongated body 1 by using the measure 5 as a marker when determining the XYZ coordinates within the shaft 50.

[0049] A 3D point cloud 30 is created in the 3D point cloud generation unit from the image inside the shaft 50 and the XYZ coordinates inside the shaft 50 obtained as described above (see Figure 5), and the changes in the state of the shaft 50 are confirmed using this 3D point cloud 30.

[0050] Specifically, as illustrated in Figure 6, for example, three-dimensional point clouds 30 are obtained at different time periods, such as years or months, and these three-dimensional point clouds 30 are compared and examined to confirm changes in the state of the inner wall surface of the shaft 50, such as damage (cracking), displacement (movement of the shaft 50), and deformation (bending deformation of the shaft 50).

[0051] Therefore, according to this embodiment, the coordinates inside the shaft 50 can be accurately determined by a simple method without using particularly high-precision and expensive equipment, thereby obtaining a high-precision 3D point cloud 30, and thus the changes in the state of the shaft 50 can be confirmed effectively.

[0052] Furthermore, in this embodiment, since the markers 1a are provided on the elongated body 1 at 1m intervals, it is easy to confirm the depth position of the markers 1a, and the coordinates within the shaft 50 can be determined accurately. In this respect as well, the aforementioned effects are reliably achieved.

[0053] Furthermore, in this embodiment, since the surface of the elongated body 1 has alternating color display sections 1' of different colors arranged at 1m intervals, and the boundary lines between the color display sections 1' are configured as marker sections 1a, it is easy to confirm the depth position of the marker sections 1a, thus ensuring that the aforementioned effects are reliably achieved in this respect as well.

[0054] Furthermore, in this embodiment, the long body 1 is suspended into the shaft 50 from multiple positions on the same plane at the upper opening of the shaft 50, specifically from positions A1 and A2 of XYZ coordinates, and a measuring tape 5 is also suspended into the shaft 50. The shaft 50 is then photographed using appropriate photographic means to create an image of the inside of the shaft 50 that includes the marker portion 1a of each long body 1 and the length scale portion 5a of the measuring tape 5. Since the XYZ coordinates on the same horizontal plane inside the shaft 50 can be determined from the marker portion 1a of each long body 1 and the length scale portion 5a of the measuring tape 5, the orientation of the shaft 50 (3D point cloud 30) can be determined by providing multiple coordinate axes, thus reliably achieving the aforementioned effects.

[0055] Furthermore, the present invention is not limited to this embodiment, and the specific configuration of each constituent element can be designed as appropriate. [Explanation of Symbols]

[0056] A1 position A2 position 1. Long body 1' Color display section 1a Marker section 5 Major 5a Length scale section 30 3D point clouds 50 shafts

Claims

1. A method for confirming the state of a shaft, comprising confirming changes in the state of the shaft using a three-dimensional point cloud created from an image of the inside of the shaft and the XYZ coordinates inside the shaft, wherein a long, rigid body with markings provided at equal intervals inside the shaft is suspended from a specific XYZ coordinate position at the upper opening of the shaft, and a lightweight, wide measuring tape with a length scale on its surface is suspended inside the shaft, the shaft is photographed using an appropriate photographic means to create an image of the inside of the shaft that includes the markings of the long body and the length scale of the measuring tape, and the three-dimensional point cloud is created from this image to confirm changes in the state of the shaft.

2. A method for checking the condition of a shaft according to claim 1, characterized in that the markers are provided on the elongated body at 1m intervals.

3. A method for checking the condition of a shaft according to either claim 1 or 2, characterized in that different colored indicator sections are alternately arranged on the surface of the long body at 1m intervals, and the boundaries between the colored indicator sections are configured as the indicator sections.

4. A method for confirming the condition of a shaft according to either claim 1 or 2, characterized in that the elongated body is suspended into the shaft from multiple positions on the same plane at the upper opening of the shaft, each from a position with specific XYZ coordinates, and the measuring tape is suspended into the shaft, and the shaft is photographed using an appropriate photographic means to create an image of the inside of the shaft that includes the markings on each of the elongated bodies and the length scale of the measuring tape.

5. A method for confirming the condition of a shaft according to claim 3, characterized in that the long object is suspended into the shaft from multiple positions on the same plane at the upper opening of the shaft, each from a position with specific XYZ coordinates, and the measuring tape is suspended into the shaft, and the shaft is photographed using an appropriate photographic means to create an image of the inside of the shaft that includes the markings on each of the long objects and the length scale of the measuring tape.

Images