Laser scan data processing device, laser scan method and program

Abstract

To perform laser scanning for the cross section of a tunnel with as little scanned amount as possible.SOLUTION: Provided is a method for scanning with a laser inside a tunnel 100 using a laser scanner that includes a horizontal rotation unit, a vertical rotation unit which is disposed in the horizontal rotation unit, and an optical unit which is disposed in the vertical rotation unit, for irradiation and reception of laser scanning light. The method acquires the laser scanned data of left and right wall surfaces of the tunnel 100, connects between the left and right wall surfaces on the basis of the laser scanned data, finds a straight line that intersects a perpendicular passing through a position P where the laser scanner that has acquired the laser scanned data is installed, finds a direction orthogonal to the straight line in the horizontal plane, and performs laser scanning while rotating the vertical rotation unit around said direction as the axis of rotation, thereby scanning the cross section of the tunnel 100 with a laser.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technology of laser scanning. [Background technology]

[0002] In tunnel construction, it is necessary to check whether the work has been carried out according to the drawings. One possible method for doing this is to use laser scanning. Laser scanning technology for tunnel inner walls is well known, for example, as described in Patent Document 1 and Patent Document 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-188956 [Patent Document 2] Patent No. 5648831 Summary of the Invention [Problem to be solved by the invention]

[0004] At tunnel construction sites, the cross-sectional shape of the tunnel is checked. One possible method for obtaining the cross-sectional shape of the tunnel using laser scanning is to laser scan the entire tunnel inner wall. However, this method requires a long time for the laser scanning work and also involves handling a large amount of data.

[0005] In this context, an object of the present invention is to provide a technology for performing laser scanning of a cross section of a tunnel with as little scanning volume as possible. [Means for solving the problem]

[0006] The present invention is a laser scan data processing device that includes a laser scan data acquisition unit that acquires laser scan data of the left and right wall surfaces of a tunnel, and a calculation unit that, based on the laser scan data, calculates a straight line A that connects the left and right wall surfaces and intersects with a perpendicular line passing through the installation position of the laser scan device that obtained the laser scan data, and further calculates a direction perpendicular to the straight line A in a horizontal plane, where the straight line A is a line that connects the left and right wall surfaces over the shortest distance or a line that is perpendicular to at least one of the left and right wall surfaces.

[0007] In the present invention, an embodiment is that the calculation unit calculates the left and right wall surfaces based on the laser scan data, and based on the calculated left and right wall surfaces, determines a straight line A that connects the left and right wall surfaces and intersects with a perpendicular line that passes through the installation position of the laser scan device that obtained the laser scan data.

[0008] In the present invention, the laser scanning device includes a horizontal rotation unit, a vertical rotation unit arranged on the horizontal rotation unit, and an optical unit arranged on the vertical rotation unit for irradiating and receiving laser scanning light, and the laser scanning data is obtained by rotating the horizontal rotation unit within a limited range and performing laser scanning while rotating the vertical rotation unit.

[0009] In the present invention, the laser scanning device includes a horizontal rotation unit, a vertical rotation unit disposed on the horizontal rotation unit, and an optical unit disposed on the vertical rotation unit for irradiating and receiving laser scan light, and the laser scan data is a first laser scan point cloud and a second laser scan point cloud distributed in a line along each of the left and right wall surfaces obtained by laser scanning while rotating the horizontal rotation unit with the optical axis of the optical unit fixed horizontally, and the calculation unit calculates a first line that fits to the first laser scan point cloud and a second line that fits to the second laser scan point cloud, and calculates as the straight line A a straight line that connects the first line and the second line over the shortest distance or a straight line that is perpendicular to at least one of the first line and the second line.

[0010] In the present invention, the laser scanning device comprises a horizontal rotation unit, a vertical rotation unit arranged on the horizontal rotation unit, and an optical unit arranged on the vertical rotation unit for irradiating and receiving laser scanning light, the laser scan data being a first laser scan point cloud distributed linearly along one of the left and right wall surfaces obtained by laser scanning while rotating the horizontal rotation unit with the optical axis of the optical unit fixed horizontally, and the calculation unit may calculate a first line fitting to the first laser scan point cloud and calculate a straight line perpendicular to the first line as line A.

[0011] The present invention is a laser scanning method for inside a tunnel using a laser scanning device that includes a horizontal rotation unit, a vertical rotation unit located on the horizontal rotation unit, and an optical unit located on the vertical rotation unit that emits and receives laser scanning light. This laser scanning method includes obtaining laser scan data for the left and right wall surfaces of the tunnel, determining, based on the laser scan data, a straight line A that connects the left and right wall surfaces and intersects with a perpendicular line passing through the installation position of the laser scanning device that obtained the laser scan data, determining a direction B that is perpendicular to the straight line A in the horizontal plane, and performing a laser scan while rotating the vertical rotation unit around the direction B as the rotation axis, thereby performing a laser scan of the cross section of the tunnel, wherein the straight line A is a straight line that connects the left and right wall surfaces over the shortest distance or a straight line that is perpendicular to at least one of the left and right wall surfaces.

[0012] The present invention is a program that is read and executed by a computer, and causes the computer to operate as a laser scan data acquisition unit that acquires laser scan data of the left and right wall surfaces of a tunnel, and as a calculation unit that, based on the laser scan data, calculates a straight line A that connects the left and right wall surfaces and intersects with a perpendicular line passing through the position of the laser scanning device that obtained the laser scan data, and further calculates a direction perpendicular to the straight line A in a horizontal plane, wherein the straight line A is a straight line that connects the left and right wall surfaces over the shortest distance or a straight line that is perpendicular to at least one of the left and right wall surfaces. [Effects of the Invention]

[0013] According to the present invention, a technique for performing laser scanning of a cross section of a tunnel using as little scanning volume as possible is provided. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a conceptual diagram illustrating the principle of the invention. [Figure 2] FIG. 1 is a conceptual diagram illustrating the principle of the invention. [Figure 3] FIG. 1 is a conceptual diagram illustrating the principle of the invention. [Figure 4] FIG. 1 is a diagram illustrating the appearance of a laser scanning device. [Figure 5] FIG. 2 is a block diagram of a laser scanning device and a data processing device. [Figure 6] 10 is a flowchart illustrating an example of a processing procedure. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1. First embodiment (overview) Here, we consider a case where a laser scan of the cross section of tunnel 100 is performed by laser scanning device 200 (see FIG. 4) installed at point P in FIG. 1. Point P is a point that corresponds to the mechanical point of the surveying instrument, and in this case, it is the optical origin (origin of distance measurement and azimuth measurement) of laser scanning device 200, or a point on the installation surface obtained by drawing a perpendicular line from the optical origin to the installation surface. FIGS. 1 to 3 show a case where point P is the point on the installation surface obtained by drawing a perpendicular line from the optical origin of laser scanning device 200 to the installation surface (tunnel road surface).

[0016] First, let's define the cross section of a tunnel. The cross section of a tunnel is defined as a cross section perpendicular to the tunnel's axis. The tunnel axis is a line that indicates the axis of the tunnel and extends in the direction of the tunnel's extension. If the tunnel is straight, the axis of the tunnel will be a straight line.

[0017] FIG. 1 shows a tunnel 100 that is slightly curved. In this case, the axis 120 of the tunnel 100 is a curve. In this case, the direction of the tunnel axis 120 at a certain location is the direction of the tangent to the axis 120 at that location. Note that if the tunnel 100 is inclined in the extension direction (like a slope in road terms), the axis will tilt up and down. In that case, the horizontal component of the axis is considered to be the direction of the tunnel axis.

[0018] To obtain laser scan data of the tunnel cross section at point P, the direction of the tangent to the axis 120 at point P is obtained, and laser scanning is performed in a direction perpendicular to that direction. This provides a laser scan point cloud of the tunnel inner wall cut by the cross section. For example, if the tunnel 100 is horseshoe-shaped, a horseshoe-shaped laser scan point cloud is obtained.

[0019] Here, the direction of axis 120 of point P is obtained by the following method. Figure 3 is a schematic diagram of the tunnel 100 in Figure 1 with the ceiling removed, showing the road surface (underside) and the left and right side walls. As shown in Figure 3, a straight line L3 (which is a straight line along the cross section) that intersects with the perpendicular line passing through point P and connects the left and right wall surfaces S1 and S2 of the tunnel in the shortest distance is found, and a vector V that is perpendicular to this line L3 in the horizontal direction is found.

[0020] The direction of this vector V is then acquired as the direction of axis 120 (see FIG. 1) at point P. Once the direction of axis 120 is known, a vertical scan (V scan) is performed in a direction perpendicular to that direction to obtain a laser scan point cloud of the cross section of tunnel 100 at point P.

[0021] (Hardware configuration) 1 shows the appearance of a laser scanning device (laser scanner) 200. The laser scanning device 200 includes a tripod 211, a base unit 212 fixed to the top of the tripod 211, a horizontal rotation unit 213 which is a rotation body capable of horizontal rotation on the base unit 212, and a vertical rotation unit 214 which is a rotation body capable of vertical rotation relative to the horizontal rotation unit 213.

[0022] The vertical rotation unit 214 includes an optical unit 215 that emits and receives laser scanning light. Pulses of laser scanning light are emitted from the optical unit 215. This pulse emission occurs along a direction (plane) perpendicular to the rotation axis (axis extending in the horizontal direction) of the vertical rotation unit 214 while the vertical rotation unit 214 rotates. In this case, pulses of laser scanning light are emitted from the optical unit 215 along the vertical angle direction.

[0023] While the horizontal rotation unit 213 is rotated horizontally and the vertical rotation unit 214 is rotated vertically, pulsed laser scanning light is emitted from the optical unit 215, and the reflected light from the target object is received by the optical unit 215, thereby performing a laser scan of the surroundings.

[0024] That is, by emitting pulses of laser scanning light from the optical unit 215 while rotating the vertical rotation unit 214 vertically, scanning along the vertical angle direction (vertical scanning) is performed, and at the same time, by rotating the horizontal rotation unit 213 horizontally, the scanning line (scanning line) along this vertical angle direction moves so as to be shifted along the horizontal angle direction. Note that if horizontal rotation is also performed simultaneously with vertical rotation, the scanning along the vertical angle direction is not completely along the vertical direction, but is performed along a slightly oblique line. Note that if the horizontal rotation unit 213 does not rotate, the scanning along the vertical angle direction will be along the vertical direction.

[0025] Furthermore, by fixing the vertical rotation unit 214 so that the optical axis direction of the optical unit 215 is horizontal, and rotating the horizontal rotation unit 213 in this state while emitting pulses of laser scanning light from the optical unit 215, it is possible to perform laser scanning that is narrowed in the horizontal direction. In this case, if the range of the rotation angle of the horizontal rotation unit 213 is 360°, horizontal laser scanning is performed over a surrounding 360° range. Furthermore, if the range of the rotation angle of the horizontal rotation unit 213 is narrowed to a specific angle range, horizontal laser scanning is performed within that horizontal angle range.

[0026] Motors are used to rotate the horizontal rotation unit 213 and the vertical rotation unit 214. The horizontal rotation angle of the horizontal rotation unit 213 and the vertical rotation angle of the vertical rotation unit 214 are precisely measured by encoders.

[0027] The laser scanning light is a single pulse of distance measurement light, and one laser scanning light measures the distance to the scanning point, which is the reflection point where the laser scanning light hits. The position of the scanning point (the reflection point of the laser scanning light) relative to the laser scanning device 200 is calculated from this measured distance value and the irradiation direction of the laser scanning light.

[0028] If the exterior orientation parameters (position and orientation) of the laser scanning device 200 in an absolute coordinate system are known, the positions of the scan points in the absolute coordinate system can be determined. Absolute coordinate systems are used in maps and GNSS. In absolute coordinate systems, positions are described by, for example, latitude, longitude, and altitude. It is also possible to obtain a laser scan point cloud in a local coordinate system whose origin is the optical origin of the laser scanning device 200.

[0029] The laser scan point cloud output from the laser scanning device 200 can be in the form of outputting distance and direction data for each point (each scan point). It is also possible to calculate the position of each point in a specific coordinate system within the laser scanning device 200 and output the three-dimensional coordinate position of each point as point cloud data. The laser scan point cloud data also includes information on the brightness (intensity of reflected light) of each scan point.

[0030] 5 is a block diagram of the laser scanning device 200 and the tunnel axis direction calculation device 300. The laser scanning device 200 includes a light emitting unit 201, a light receiving unit 202, a distance measuring unit 203, a direction obtaining unit 204, a light emission control unit 205, a drive control unit 206, a marking light control unit 207, and a communication unit 208.

[0031] The light-emitting unit 201 has a light-emitting element that emits laser scanning light, an optical system related to light emission, and peripheral circuits. The laser scanning light from the light-emitting unit 201 is emitted to the outside from the optical unit 215 via the optical system. The light-receiving unit 202 has a light-receiving element that receives the laser scanning light, an optical system related to light reception, and peripheral circuits. The reflected light of the laser scanning light taken in by the optical unit 215 is guided to the light-receiving unit 202 via the optical system.

[0032] The distance measuring unit 203 calculates the distance from the laser scanning device 200 to the reflection point of the laser scanning light. In this example, a reference optical path is provided inside the laser scanning device 200. The laser scanning light output from the light emitting element is split into two, one of which is irradiated onto the target from the optical unit 215 as laser scanning light, and the other is guided to the reference optical path as reference light.

[0033] The laser scanning light reflected from the object and taken in by the optical unit 215 and the reference light propagating through the above-mentioned reference optical path are combined and input to the light receiving unit 202. The laser scanning light and the reference light have different propagation distances, and the reference light is detected first by the light receiving element, and then the laser scanning light is detected by the light receiving element.

[0034] Looking at the output waveform of the light receiving element, the detected waveform of the reference light is output first, followed by the detected waveform of the laser scanning light after a time lag. The distance to the reflection point of the laser scanning light is calculated from the phase difference (time difference) between these two waveforms. Note that it is also possible to calculate the distance from the flight time of the laser scanning light.

[0035] The direction acquisition unit 204 acquires the direction of the optical axis of the laser scanning light. The direction of the optical axis is obtained by measuring the angle of the optical axis in the horizontal direction and the angle of the optical axis in the vertical direction. The direction acquisition unit 204 has a horizontal angle detection unit 204a and a vertical angle detection unit 204b.

[0036] The horizontal angle detection unit 204a detects the horizontal rotation angle of the horizontal rotation unit 213. Horizontal rotation is rotation around the vertical direction as the rotation axis. The angle is detected by an encoder. The vertical angle detection unit 204b detects the vertical rotation angle of the vertical rotation unit 214. Vertical rotation is rotation around the horizontal direction as the rotation axis. The angle is detected by an encoder.

[0037] By measuring the horizontal rotation angle of the horizontal rotation unit 213 and the vertical rotation angle of the vertical rotation unit 215, the direction of the optical axis of the laser scanning light as seen from the laser scanning device 200, i.e., the direction of the scanning point, can be determined. The light emission control unit 205 controls the emission timing of the laser scanning light in the light emitting unit 201.

[0038] The drive control unit 206 includes a horizontal rotation drive control unit 206a that performs drive control to rotate the horizontal rotation unit 213 horizontally, and a vertical rotation drive control unit 206b that performs drive control to rotate the vertical rotation unit 214 vertically.

[0039] The marking light control unit 207 controls the light emitting unit 202 to emit laser light at a specified point, thereby achieving the function of a laser pointer. The communication unit 208 communicates with the tunnel axis direction calculation device 300 and other devices. A wireless LAN or a mobile phone line is used for communication.

[0040] The tunnel axis direction calculation device 300 is an example of a processing device for point cloud data obtained by laser scanning, and calculates the direction of the axis of the tunnel at a certain point inside the tunnel.

[0041] The tunnel axis direction calculation device 300 is configured by a computer. The computer is, for example, a PC (personal computer), and has a CPU, a storage device, a user interface, a communication interface, and other functions that a normal PC has. A dedicated computer can be prepared as the tunnel axis direction calculation device 300. It is also possible to realize the tunnel axis direction calculation device 300 using a data processing server. It is also possible to incorporate the tunnel axis direction calculation device 300 into the laser scanning device 200.

[0042] The tunnel axis direction calculation device 300 includes a point cloud data acquisition unit 301, a calculation unit 302 for a line extending horizontally along the wall surface, and a calculation unit 304 for the tunnel axis direction at the installation position of the laser scanning device. These functional units are configured as software by having the CPU of the PC run an application program installed on the PC to be used. Some or all of these functional units can also be configured as dedicated hardware. The tunnel axis direction calculation device 300 also includes a communication unit 304 that uses the communication interface of the PC to be used.

[0043] The point cloud data acquisition unit 301 receives and acquires the data of the laser scan point cloud (point cloud data) acquired by the laser scanning device 200.

[0044] The calculation unit 302 for calculating a line extending horizontally along the wall surface and the calculation unit 303 for calculating the axial direction of the tunnel at the installation position of the laser scanning device constitute an arithmetic unit 310 that calculates the axial direction of the tunnel 100 at point P.

[0045] A calculation unit 302 for lines extending horizontally along the wall surface calculates lines L1 and L2 in Fig. 3. Details of the processing will be described later.

[0046] A calculation unit 303 for the tunnel axis direction at the installation position of the laser scanning device calculates the direction of vector V at point P in Fig. 3. Details of the calculation of the direction of vector V will be described later.

[0047] The communication device 304 communicates with the laser scanning device 200 and other devices. The communication is performed using a wireless LAN or a mobile phone line.

[0048] (Example of processing) An example of the processing procedure is shown in Figure 6. The program for executing the processing shown in Figure 6 is stored in a storage device of a PC constituting the tunnel axis direction calculation device 300, and is read and executed by the CPU of the PC. It is also possible to store the program in an appropriate storage medium and read it from there for use.

[0049] First, the laser scanning device 200 is placed at point P. Here, it is assumed that the position of point P coincides with the position of the optical origin of the laser scanning device 200 on the horizontal plane (XY plane). Furthermore, it is assumed that the laser scanner 200 is placed horizontally at point P, but its exact orientation in the horizontal direction is unknown. Of course, it is assumed that the approximate orientation is known by visual estimation.

[0050] In this state, the horizontal rotation unit 213 of the laser scanning device 200 is rotated within a range of ±θ horizontal angle around a direction perpendicular to the approximate extension direction of the tunnel 100 (the direction of the tunnel axis), and the vertical rotation unit 214 is rotated vertically to perform vertical scanning. θ is set to 5° to 30°.

[0051] This laser scanning results in the acquisition of laser scan point clouds of the wall surfaces S1 and S2 of the tunnel 100 (step S101), as shown in Figure 2. Wall surface S1 is the left wall surface when viewed in the positive direction of the Y axis, and wall surface S2 is the right wall surface when viewed in the positive direction of the Y axis. Note that the laser scan point clouds of the ceiling and floor surfaces are not used.

[0052] Next, a surface that fits to the laser scan point clouds of wall surfaces S1 and S2 is obtained. In other words, the equations of the surfaces of wall surfaces S1 and S2 are obtained. Note that the target surfaces are not limited to flat surfaces, but may also be curved. Therefore, the equations of the surfaces obtained are equations of flat or curved surfaces. Once the equations of the surfaces of wall surfaces S1 and S2 are obtained, a line L1 that crosses wall surface S1 horizontally and a line L2 that crosses wall surface S2 horizontally are obtained (step S102). The processing of step S102 is performed in the "calculation unit 302 for lines extending horizontally along the wall surfaces." Note that the Z-direction positions (height positions) of L1 and L2 are assumed to be the same.

[0053] If the tunnel 100 is straight, L1 and L2 will be straight. If the tunnel 100 is not straight, L1 and L2 will be curved according to the degree of curvature of the tunnel 100.

[0054] Another method is to find L1 and L2 by finding a line L1 that fits horizontally to the laser scan point cloud of wall surface S1 and a line L2 that fits horizontally to the laser scan point cloud of wall surface S2. Another method is to extract a point cloud in a narrow range in the vertical direction (for example, a width of ±1 cm above or below) that can be considered to be at the same height, and use this ribbon-like region (a linear region with a certain width) as L1 and L2.

[0055] Once L1 and L2 have been determined, a perpendicular line passing through point P is set, as shown in Figure 3, and a straight line L3 that intersects with this perpendicular line and connects L1 and L2 in the shortest distance is determined (step S103). The direction perpendicular to this straight line L3 in the horizontal plane becomes the direction 121 of the axis 120 of tunnel 100 at point P (step S104). The processing of steps S103 and S104 is performed in the "tunnel axis direction calculation unit 303 at the installation position of the laser scanning device."

[0056] Once the direction 121 (direction of vector V) of the axis 120 of the tunnel 100 at point P is obtained, a vertical laser scan is performed in a direction perpendicular to the direction 121 using the laser scanning device 200 (step S105).

[0057] Specifically, first, horizontal rotation unit 213 is rotated horizontally to align the axial direction of the rotation axis of vertical rotation unit 214 with direction 121. Then, in this state, horizontal rotation unit 213 is fixed and vertical rotation unit 214 is rotated to perform laser scanning. That is, vertical rotation unit 214 is rotated with direction 121 as the rotation axis, and laser scanning is performed. As a result, laser scan point cloud data of the cross section of tunnel 100 at point P is obtained.

[0058] (Additional explanation) An example of how to select point P is explained below. First, the position of the part just before the tunnel entrance is precisely determined. This positioning is performed using a known reference point or relative GNSS positioning. This position is set as the starting point P0, and position P1 within the tunnel visible from there is determined. The position of P1 is determined in advance on the map. The same applies to P2, P3, P4, ... Pn after P1.

[0059] For example, the position of P1 is marked using the laser scanning device 200 installed at P0 by using the laser pointer function of the laser scanning device 200 to be used. Of course, the position of P1 may also be determined using other surveying means.

[0060] Once the position of P1 is determined, a laser scanning device 200 is installed there, and the process of FIG. 6 is performed to obtain laser scan data of the cross section of the tunnel at that point.

[0061] The same process is repeated for P2 and onwards to obtain laser scan data of the tunnel cross section at P1, P2, P3, P4, ..., Pn.

[0062] (superiority) The laser scans of the wall surfaces S1 and S2 shown in Figure 2 are partial laser scans, and the amount of scanning does not increase significantly. Therefore, it is possible to perform laser scanning of the cross section of the tunnel with as little scanning as possible.

[0063] The point P where the laser scanner is installed does not need to be the center of the tunnel in the width direction, but the axial direction of the tunnel can be calculated.

[0064] 2. Second embodiment In step S101 of Fig. 6, the vertical rotation unit 214 of the laser scanning device 200 is fixed in a horizontally oriented state, and laser scanning is performed while only the horizontal rotation unit 213 is rotated. In this case, linear laser scanning is performed only in the horizontal direction, and a linearly distributed laser scan point cloud is obtained on the wall surfaces S1 and S2. L1 and L2 in Fig. 3 are obtained by finding a line that fits this linearly distributed laser scan point cloud. The rest is the same as in the first embodiment. When implementing this embodiment, a calculation unit 310 that performs the calculation described above is prepared. This is the same as in the other embodiments.

[0065] Here, it is preferable that the horizontal angle scanning range of the horizontal rotation unit 213 be limited to a range of, for example, 60° or 90°. Specifically, this is done as follows: First, point the optical axis of the laser scan 200 toward the wall surface. At this time, visual estimation is sufficient, and efforts are made to orient the optical axis perpendicular to the wall surface S1 or S2. Then, horizontal scanning is performed within a range of ±30° from that state. This reduces unnecessary scanning and the amount of data.

[0066] 3. Third embodiment There is also a method of determining the wall surfaces S1 and S2 by performing a scan by rotating the horizontal rotation unit 213 while the vertical rotation unit 214 is fixed at multiple angles. For example, laser scanning is performed by rotating the horizontal rotation unit 213 while the vertical rotation unit 214 is fixed with the optical unit 215 facing an elevation angle of 0° (horizontal), laser scanning is performed by rotating the horizontal rotation unit 213 while the vertical rotation unit 214 is fixed with the optical unit 215 facing an elevation angle of 10°, and laser scanning is performed by rotating the horizontal rotation unit 213 while the vertical rotation unit 214 is fixed with the optical unit 215 facing an elevation angle of 20°.

[0067] This laser scan performs three horizontal scans on the wall surface, obtaining three laser scan point clouds. By finding a surface that fits these three laser scan point clouds, the equations of the wall surfaces S1 and S2 are calculated. Note that the trajectory of the laser scan point clouds on the wall surface obtained by horizontal scanning at an elevation angle other than 0° will not be a straight line.

[0068] The selection of the vertical angle (the elevation angle in the above case) is not limited to the three steps mentioned above, but may be two steps or four or more steps. Also, the selection of the angle interval is not limited to the 10° steps mentioned above, but values ​​such as 5° steps or 15° steps can be selected.

[0069] This method can reduce the amount of laser scan data. In this case, too, by limiting the horizontal angle scan range of the horizontal rotation unit 213, it is possible to reduce unnecessary scans and the amount of data.

[0070] As a variation of the horizontal-only laser scanning described above, horizontal scanning is performed on only one of the wall surfaces S1 and S2, and only one of L1 and L2 is acquired. In this case, a straight line L3 is obtained that is orthogonal to L1 or L2 in the horizontal direction and passes vertically above point P (intersecting with the perpendicular line passing through point P).

[0071] 4. Fourth Embodiment In step S103, the straight line L3 can also be determined as a line that intersects the horizontal line L1 and / or L2 at right angles and that passes through the point P.

[0072] 5. Fifth Embodiment The straight line L3 can also be determined as a line that is horizontally perpendicular (orthogonal) to at least one of the wall surfaces S1 and S2 and intersects with the perpendicular line that passes through the point P.

[0073] 6. Sixth Embodiment Another method is to simply determine the cross-sectional direction at that location from the design data and perform scanning in that direction. In this case, first perform an initial laser scan using the method described in the other embodiments. Note that the laser scanning device 200 is assumed to be installed at point P.

[0074] The point cloud data obtained by the initial laser scan is then compared with the 3D data of the design drawing of the tunnel 100, and a search is made for a portion of the design data where the point cloud data fits. At this time, the above search is performed using the position of point P on the design data and data on the axial direction of the tunnel obtained by the method shown in another embodiment.

[0075] Once the drawing data to be fitted to the point cloud data is obtained, the drawing data is used to determine the orientation of the laser scanning device 200 relative to the tunnel 100 by the resection method. At this time, the position P is also determined, but since the position P is determined in the design data, it is known at this stage.

[0076] Next, the direction of the cross section of the tunnel 100 at the position P is obtained from the design data, and a laser scan is performed in that direction. As a result, laser scan data of the cross section of the tunnel 100 at the point P is obtained.

[0077] 7. Seventh Embodiment In the laser scanning device 200, a slight tilt of the vertical rotation axis may cause the vertical scan to be slightly tilted relative to the vertical plane. This tilt is detected during the final adjustment stage before the laser scanning device is shipped from the factory, and its effect is corrected when calculating the laser scanner point cloud.

[0078] However, this correction is performed on the acquired point cloud data, and is not appropriate when it is necessary to accurately scan the cross section of a tunnel.

[0079] Therefore, in order to suppress the influence of the tilt, the laser scanning device 200 is installed at a slight tilt so as to cancel the influence based on the tilt data obtained in advance.

[0080] For example, suppose that the rotation axis of the vertical rotation unit 214 is not completely horizontal with respect to the horizontal rotation unit 213, but is tilted by 0.05° from the horizontal. In this case, by installing the laser scanning device 200 tilted by 0.05° to cancel out the tilt, the tilt of the rotation axis of the vertical rotation unit 214 from the horizontal is brought as close to 0° as possible.

[0081] Usually, a leveling mechanism for finely adjusting the attitude is arranged on the base part 212, and it is possible to finely adjust the tilt of the laser scanning device 200. The tilt is adjusted using this adjustment mechanism. [Explanation of symbols]

[0082] 100...tunnel, 120...tunnel axis, 200...laser scanning device, 211...tripod, 212...base unit, 213...horizontal rotation unit, 214...vertical rotation unit, 215...optical unit.

Claims

1. a laser scan data acquisition unit that acquires laser scan data from a laser scanning device on the left and right walls of the tunnel; a calculation unit that calculates a straight line A that connects the left and right wall surfaces and intersects with a perpendicular line passing through the installation position of the laser scanning device that obtained the laser scanning data, based on the laser scanning data, and further calculates a direction that is perpendicular to the straight line A in a horizontal plane; Equipped with A laser scan is performed on the cross section of the tunnel by performing a laser scan with a direction perpendicular to the straight line A in a horizontal plane as a rotation axis, A laser scan data processing device, wherein the straight line A is a straight line connecting the left and right wall surfaces at the shortest distance or a straight line perpendicular to at least one of the left and right wall surfaces.

2. 2. The laser scan data processing device according to claim 1, wherein the calculation unit calculates the left and right wall surfaces based on the laser scan data, and based on the calculated left and right wall surfaces, determines a straight line A that connects the left and right wall surfaces and intersects with a perpendicular line that passes through an installation position of the laser scan device that obtained the laser scan data.

3. The laser scanning device A horizontal rotating part; a vertical rotation unit disposed on the horizontal rotation unit; an optical unit that is disposed on the vertical rotation unit and that irradiates and receives laser scanning light; Equipped with 3. The laser scan data processing device according to claim 1, wherein the laser scan data is obtained by laser scanning while rotating the horizontal rotation unit within a limited range and rotating the vertical rotation unit.

4. The laser scanning device A horizontal rotating part; a vertical rotation unit disposed on the horizontal rotation unit; an optical unit that is disposed on the vertical rotation unit and that irradiates and receives laser scanning light; Equipped with the laser scan data is a first laser scan point cloud and a second laser scan point cloud that are linearly distributed along the left and right wall surfaces, respectively, obtained by laser scanning while rotating the horizontal rotation unit with the optical axis of the optical unit fixed in the horizontal direction; 2. The laser scan data processing device according to claim 1, wherein the calculation unit calculates a first line that fits to the first laser scan point cloud and a second line that fits to the second laser scan point cloud, and calculates as the straight line A a straight line that connects the first line and the second line over the shortest distance or a straight line that is perpendicular to at least one of the first line and the second line.

5. The laser scanning device A horizontal rotating part; a vertical rotation unit disposed on the horizontal rotation unit; an optical unit that is disposed on the vertical rotation unit and that irradiates and receives laser scanning light; Equipped with the laser scan data is a first laser scan point cloud distributed linearly along one of the left and right wall surfaces, obtained by laser scanning while rotating the horizontal rotation unit with the optical axis of the optical unit fixed in a horizontal direction; The laser scan data processing device according to claim 1 , wherein the calculation unit calculates a first line that fits to the first laser scan point cloud, and calculates a straight line perpendicular to the first line as a straight line A.

6. A horizontal rotating part; a vertical rotation unit disposed on the horizontal rotation unit; an optical unit that is disposed on the vertical rotation unit and that irradiates and receives laser scanning light; A laser scanning method in a tunnel using a laser scanning device comprising: Obtain laser scan data of the left and right walls of the tunnel; Based on the laser scan data, a straight line A is determined that connects the left and right wall surfaces and intersects with a perpendicular line passing through the installation position of the laser scan device that obtained the laser scan data, and a direction B that is perpendicular to the straight line A in a horizontal plane is determined; By performing laser scanning while rotating the vertical rotating part with the direction B as the rotation axis, a laser scan of the cross section of the tunnel is performed. A laser scanning method in which the straight line A is a straight line that connects the left and right wall surfaces over the shortest distance or a straight line that is perpendicular to at least one of the left and right wall surfaces.

7. A program to be read and executed by a computer, Computer a laser scan data acquisition unit that acquires laser scan data of the left and right walls of the tunnel; a calculation unit that calculates a straight line A that connects the left and right wall surfaces and intersects with a perpendicular line passing through the installation position of the laser scanning device that obtained the laser scanning data, based on the laser scanning data, and further calculates a direction that is perpendicular to the straight line A in a horizontal plane; and run it, A laser scan is performed on the cross section of the tunnel by performing a laser scan with a direction perpendicular to the straight line A in a horizontal plane as a rotation axis, The straight line A is a straight line that connects the left and right wall surfaces at the shortest distance or a straight line that is perpendicular to at least one of the left and right wall surfaces.

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