JP7636740B2 - Three-dimensional model generating method and three-dimensional model generating system - Google Patents

Description

The present invention relates to three-dimensional model generation and a three-dimensional model generation system.

When a concrete deck slab on a bridge is installed on the main girders and the slab deteriorates, it becomes necessary to remove the slab from the main girders and install a new slab. In this case, the new slab is a precast slab manufactured in a factory, and there is a construction method for constructing a new road bridge by arranging multiple slabs in the bridge axis direction (for example, Patent Document 1).

JP 2009-264040 A

When carrying out a construction method such as that exemplified in Patent Document 1, the precast deck slab is placed on the existing main girder, and mortar is filled between the upper flange of the main girder and the deck slab while adjusting the road surface height at the front and rear.
The existing deck is made by pouring concrete on-site, so it does not have the exact same dimensions as the design drawings. Therefore, when replacing an existing deck, in order to match the road surface level before and after construction, it is necessary to measure the dimensions and elevation of each point before removing the deck, and then manufacture the precast deck according to the measurement results. In this case, it is necessary to measure the exact dimensions and elevation of the existing bridge, but there are issues such as traffic restrictions being required for the upper surface because it is in service, and scaffolding being required for the lower surface if it cannot be measured from the ground under the bridge, such as at high places, over rivers, or above roads.

The present invention was made in consideration of the above-mentioned problems, and provides a three-dimensional model generation method that generates a three-dimensional model that can measure the desired dimensions of a bridge without removing the deck when performing deck replacement work.

According to the present invention, there is provided a three-dimensional model generation method for generating a three-dimensional model of a bridge, the method including a marker placement process for placing a plurality of target markers on the bridge, a surveying process for measuring coordinates in real space for the plurality of target markers placed in the marker placement process, a scanning process for scanning the bridge with a laser scanner mounted on a robot attached to the underside of the bridge , a photographing process for photographing the bridge with a camera mounted on a drone to obtain a plurality of photographed images, a photogrammetry process for a computer to generate first three-dimensional point cloud data based on the plurality of photographed images taken in the photographing process, and a calculation process for the first three-dimensional point cloud data generated in the photogrammetry process and a second three-dimensional point cloud data obtained as a result of the scanning in the scanning process. and a model generation process of generating a three-dimensional model of the bridge by combining the first three-dimensional point cloud data and the second three-dimensional point cloud data, wherein the multiple target markers provided on the bridge in the marker placement process are placed in a scan range scanned by the laser scanner in the scanning process and in a photographing range photographed by the camera in the photographing process, respectively, and the computer in the model generation process combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the target markers included in the first three-dimensional point cloud data and a point cloud corresponding to the target markers included in the second three-dimensional point cloud data into a virtual space based on coordinates measured in the surveying process.

According to the present invention, there is provided a three-dimensional model generation method for generating a three-dimensional model of a bridge, the method comprising: a marker placement step of placing a plurality of target markers on the bridge; a scanning step of scanning the bridge with a laser scanner mounted on a robot attached to the underside of the bridge; a photographing step of photographing the bridge with a camera mounted on a drone to obtain a plurality of photographed images; a photogrammetry step of generating first three-dimensional point cloud data based on the plurality of photographed images photographed in the photographing step by a computer; and a model generation step of generating a three-dimensional model of the bridge by combining the first three-dimensional point cloud data generated in the photogrammetry step with second three-dimensional point cloud data obtained as a result of the scanning in the scanning step by the computer. the plurality of target markers placed in the marker placement step include a common target marker that is placed on the underside of the bridge at a position where a scan range scanned by the laser scanner in the scanning step and a photographing range photographed by the camera in the photographing step overlap, and in the model generation step, the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the common target marker included in the first three-dimensional point cloud data and a point cloud corresponding to the common target marker included in the second three-dimensional point cloud data to the same position in a virtual space.

According to the present invention, there is provided a 3D model generation system for generating a 3D model of a bridge, the 3D model generation system including: a plurality of target markers provided on the bridge and having coordinates in real space measured; a robot attached to the underside of the bridge; a laser scanner mounted on the robot for scanning the bridge; a drone ; a camera mounted on the drone for photographing the bridge to obtain a plurality of photographed images; and a 3D model generation system for generating first 3D point cloud data based on the plurality of photographed images photographed by the camera, and combining the first 3D point cloud data with second 3D point cloud data obtained as a result of scanning by the laser scanner to generate the 3D model. and a computer that generates a three-dimensional model of a bridge, wherein the multiple target markers are placed in a scanning range scanned by the laser scanner and in a photographing range photographed by the camera, and the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the target markers included in the first three-dimensional point cloud data and a point cloud corresponding to the target markers included in the second three-dimensional point cloud data into a virtual space based on surveyed coordinates.

According to the present invention, there is provided a three-dimensional model generation system for generating a three-dimensional model of a bridge, the system comprising: a plurality of target markers provided on the bridge; a robot attached to the underside of the bridge; a laser scanner mounted on the robot for scanning the bridge; a drone ; a camera mounted on the drone for photographing the bridge to obtain a plurality of photographed images; and a computer for generating first three-dimensional point cloud data based on the plurality of photographed images photographed by the camera, and for combining the first three-dimensional point cloud data with second three-dimensional point cloud data obtained as a result of the scan by the laser scanner to generate the three-dimensional model of the bridge; The multiple target markers include a common target marker that is located on the underside of the bridge at a position where a scanning range scanned by the laser scanner and a photographing range photographed by the camera overlap, and the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the common target marker included in the first three-dimensional point cloud data and a point cloud corresponding to the common target marker included in the second three-dimensional point cloud data to the same position in a virtual space.

The various inventions described above can generate a three-dimensional model of a bridge by combining with high precision first three-dimensional point cloud data generated by photogrammetry using images captured by a camera mounted on an aircraft, and second three-dimensional point cloud data that is the result of scanning the bridge by a laser scanner mounted on a robot attached to the underside of the bridge.
Therefore, it is possible to measure the dimensions of each part of the bridge without removing the bridge deck, and there is no need to close off traffic on the existing bridge or install scaffolding.

The present invention provides a three-dimensional model generation method that measures the desired dimensions of a bridge without removing the deck when replacing an existing deck, and generates a three-dimensional model based on the measurement results.

FIG. 1 is a configuration diagram of a three-dimensional model generation system. FIG. 2 is a schematic diagram showing the underside of a bridge to be measured. 1 is a flowchart showing an implementation procedure of the present invention. FIG. 2 is a diagram showing a display screen of a three-dimensional model.

Embodiments of the present invention will be described below with reference to the drawings. Note that in all drawings, similar components are given the same reference numerals and descriptions will be omitted where appropriate.

<Outline of the 3D model generation system 100>
First, an overview of a three-dimensional model generating system 100 will be described with reference to FIG.
FIG. 1 is a diagram showing the configuration of a three-dimensional model generation system 100 .

The 3D model generation system 100 generates a 3D model of a bridge HB to be measured. In the following explanation, the bridge HB is assumed to be a road bridge, but the type of the bridge is not limited to a road bridge and may be applied to other types of bridges.
The bridge HB is composed of a deck FS attached to the top of four main girders (main girder MG1, main girder MG2, main girder MG3, main girder MG4), a paved surface P laid with asphalt or the like on the deck FS, and a wall parapet GF which prevents vehicles and other objects traveling on the paved surface P from falling off.
Although four main girders are shown in FIG. 1, the present invention is applicable to bridges having at least two or more main girders, and the number of main girders is not limited to the example shown.

The three-dimensional model generation system 100 includes a robot 110, a laser scanner 120 mounted on the robot 110, an aircraft 130, a camera 140 mounted on the aircraft 130, and a computer 150 that generates a three-dimensional model of the bridge HB.

The robot 110 is attached to the underside of the bridge HB, and the laser scanner 120 mounted on the robot 110 scans the bridge HB (mainly the underside of the bridge HB).
The robot 110 is a mobile robot that is attached across two adjacent main girders (main girders MG1 and MG2 in the example shown in FIG. 1) among the multiple main girders MG1 to MG4 that make up the bridge HB, and is movable in the bridge axis direction of the bridge HB (the attached main girders). Specifically, the robot 110 is suspended from the bridge HB by a suspended carriage 111 having wheels that abut against the lower flange of the main girder MG1, and a suspended carriage 112 having wheels that abut against the lower flange of the main girder MG2.
The movement control of the robot 110 may be realized in response to operation by a user, or may be realized by autonomous calculation processing by the robot 110, or may be realized by a method that combines these.
The robot 110 also has a mechanism 113 for moving the laser scanner 120, and can lower the mounted laser scanner 120 to a position where the laser scanner 120 can scan the undersides of the lower flanges of the main girders MG1 and MG2. Note that, although Fig. 1 illustrates that the mechanism 113 can move the laser scanner 120 in the height direction (up and down direction), the laser scanner 120 may be moved in a direction perpendicular to the bridge axis with respect to the bridge HB (in the direction of the rails provided between the suspended carts 111 and 112).
The laser scanner 120 can scan the space between the main girders MG1 and MG2 by scanning the underside of the bridge HB from the moving position of the robot 110. Here, the laser scanner 120 has a built-in camera (not shown), and each piece of point data constituting the three-dimensional point cloud data obtained as a result of the scan contains color information given based on the image captured by the built-in camera, and the laser scanner 120 can generate color three-dimensional point cloud data for the underside of the bridge HB.

Aircraft 130 is an aircraft that flies around the bridge HB (top and side), and is preferably an unmanned aerial vehicle (a so-called drone) that is remotely controlled in response to user operation.
The camera 140 mainly captures the upper and side surfaces of the bridge HB to obtain a plurality of captured images.
The image captured by the camera 140 is used for photogrammetry, which will be described later, and from the standpoint of increasing the accuracy of the three-dimensional model reproduced by photogrammetry, it is preferable that the image have as many pixels as possible.

The computer 150 is directly or indirectly communicatively connected to the laser scanner 120 and the camera 140, and can input the results of the scan by the laser scanner 120 and multiple captured images taken by the camera 140.
The computer 150 has application software installed therein capable of implementing photogrammetry, and can generate three-dimensional point cloud data (hereinafter referred to as first three-dimensional point cloud data) obtained based on a plurality of images captured by the camera 140. Here, photogrammetry refers to a technique for performing image analysis on a large number of images obtained by capturing an object (a bridge HB in this embodiment) as a subject from multiple directions, and expressing the object three-dimensionally in a virtual space.
The computer 150 combines the first three-dimensional point cloud data generated by the above-mentioned photogrammetry and the three-dimensional point cloud data obtained as a result of scanning by the laser scanner 120 (hereinafter referred to as the second three-dimensional point cloud data) to generate a three-dimensional model of the bridge HB.
1 shows the computer 150 as a single device, the embodiment of the present invention is not limited to this, and the above processing may be realized by combining a plurality of devices. For example, a computer that generates the first three-dimensional point cloud data by photogrammetry using a plurality of images captured by the camera 140 and a computer that combines the first three-dimensional point cloud data and the second three-dimensional point cloud data may be separate computers.

Here, the computer 150 combines the first 3D point cloud data with the second 3D point cloud data based on a plurality of target markers provided on the bridge HB. Since each of the target markers is provided in real space, the position of the target marker can be measured accurately.
Due to this feature, the computer 150 can reproduce the shape of the bridge HB as a 3D model with high accuracy by combining 3D point cloud data generated by different methods (scanning by the laser scanner 120 and photogrammetry of images captured by the camera 140), and can accurately measure the positional relationship of each component. In addition, all of the above methods can be performed without removing the deck FS from the bridge HB.

<About target markers>
Next, the above-mentioned target marker will be described with reference to FIG.
FIG. 2 is a schematic diagram showing the underside of the bridge HB as the measurement target.
2 is merely a specific example, and may be changed as appropriate within the scope of the object of the present invention. In addition, although the present embodiment is described on the premise that a dedicated target marker is provided, any of the members constituting the bridge HB (having a characteristic shape) may be used as a target marker instead.

A target marker TM1 and a target marker TM2 are arranged on one of the sides of the bridge HB, and a target marker TM6 and a target marker TM7 are arranged on the other side of the bridge HB.
As described above, in this embodiment, the aircraft 130 flies over the top and sides of the bridge HB, so these four target markers correspond to the target markers located within the shooting range of the camera 140 mounted on the aircraft 130.

Target markers TM3, TM4 and TM5 are placed on the underside of bridge HB.
As described above, the robot 110 in this embodiment is suspended from the underside of the bridge HB and moves along the bridge axis, and therefore these three target markers correspond to the target markers arranged in the scan range of the laser scanner 120 mounted on the robot 110. In order to perform three-dimensional measurement of the bridge HB using the laser scanner 120, it is necessary to arrange at least three or more target markers in the scan range, and Fig. 2 shows an example of the minimum number of target markers.

It is desirable that the positions of the above target markers in real space are accurately measured so that their respective positional relationships are clear. This is because the measurement accuracy of the relative positional relationship between the target markers arranged in the shooting range of the camera 140 and the target markers arranged in the scanning range of the laser scanner 120 affects the combining accuracy of the first 3D point cloud data and the second 3D point cloud data.
When applying photogrammetry for mapping (generating first three-dimensional point cloud data), it is preferable that the computer 150 assigns a position determined in advance by the above-mentioned surveying as a reference position to a target marker captured in some of the multiple captured images, and maps a subject captured in an image in which the target marker is not captured, into a virtual space based on the reference position. This is because it is possible to eliminate distortion of the combined data caused by combining a large number of images, which is a drawback of photogrammetry, and improve mapping accuracy.

<Procedure for carrying out the present invention>
Next, a three-dimensional model generating method realized by utilizing the three-dimensional model generating system 100 will be described with reference to FIG.
FIG. 3 is a flow chart showing the implementation procedure of the present invention.

Step S110 is a step of placing a plurality of target markers on the bridge HB, and corresponds to the marker placing step according to the present invention.
As described above, the target marker placed on bridge HB in step S110 serves as the basis for combining the first three-dimensional point cloud data and the second three-dimensional point cloud data, and therefore needs to be placed in both the shooting range of camera 140 and the scanning range of laser scanner 120.

Step S120 is a process for measuring the coordinates in real space for the multiple target markers placed in step S110, and corresponds to the measurement process according to the present invention.

Step S130 is a process in which the laser scanner 120 mounted on the robot 110 attached to the underside of the bridge HB scans the bridge HB, and corresponds to the scanning process according to the present invention.
Step S140 is a process in which the camera 140 mounted on the aircraft 130 photographs the bridge HB to obtain a plurality of photographed images, and corresponds to a photographing process according to the present invention.
Although FIG. 3 illustrates the order in which step S130 is performed followed by step S140, the present invention may be implemented by performing step S140 followed by step S130, or by performing steps S130 and S140 in parallel.

As described above, the robot 110 used in step S130 is attached across the first and second main girders (e.g., main girders MG1 and MG2) of the multiple main girders that make up the bridge HB.
This allows the mounted laser scanner 120 to scan the space between the first and second main girders (e.g., main girders MG1 and MG2). This space is difficult for the aircraft 130 to fly stably, and it is difficult to obtain images sufficient to enable three-dimensional modeling by photogrammetry. However, by utilizing the robot 110 and the laser scanner 120, it is possible to create a three-dimensional model of the space by scanning with the laser scanner 120.

As described above, the robot 110 used in step S130 has a mechanism 113 that moves the laser scanner 120, and is capable of lowering the mounted laser scanner 120 to a position where the laser scanner 120 can scan the undersides of the lower flanges of the first main girder and the second main girder.
This enables the laser scanner 120 to widely scan the underside of the bridge HB (including the underside of the lower flange of the main girder).

As described above, the robot 110 used in step S130 is a mobile robot that can move in the bridge axis direction of the bridge HB. Although simply illustrated in Fig. 3, this process alternates between a process in which the robot 110 moves to a predetermined position and a process in which the robot 110 stops at the predetermined position and the laser scanner 120 scans the space between the first main girder and the second main girder, and the two processes are repeated until the entire range to be measured is scanned.
In order to perform accurate measurements, the laser scanner 120 needs to be kept stable and stationary during scanning, and is therefore suitable for mounting on the robot 110 that repeatedly moves and stops as described above.

Step S150 is a step in which computer 150 generates first three-dimensional point cloud data based on the multiple captured images taken in step S140, and corresponds to a photogrammetry step according to the present invention.
Step S160 is a process in which computer 150 combines the second three-dimensional point cloud data obtained as a result of the scan in step S110 with the first three-dimensional point cloud data obtained based on the multiple captured images taken in step S120 to generate a three-dimensional model of bridge HB, which corresponds to the model generation process of the present invention.

The process of step S160 will now be described in more detail.
As described above, the first three-dimensional point cloud data obtained by photogrammetry using the image captured by the camera 140 and the second three-dimensional point cloud data obtained as a result of scanning by the laser scanner 120 are essentially different data, and it is difficult to map them in the same virtual space without index information. Therefore, in this embodiment, when mapping each three-dimensional point cloud data in the virtual space, a point cloud corresponding to a target marker is mapped based on the coordinates of the target marker in the real space, and point clouds representing other than the target marker are mapped using the point cloud corresponding to the target marker as a reference, thereby making it possible to accurately map all point clouds.
This makes it possible to combine the first three-dimensional point cloud data and the second three-dimensional point cloud data so as to form a shape that is close to the actual shape of the bridge HB.

Step S170 is a step in which the output means (for example, the display screen of the computer 150) outputs the three-dimensional model generated in step S160 in a format that can be viewed by the user, and corresponds to the output step according to the present invention.
The output means in step S170 (output step) is not limited to a device (display device) that displays as in this embodiment, but may be a display (printer device) that prints out.

FIG. 4 is a diagram showing a display screen of a three-dimensional model.
The three-dimensional model displayed on the display screen may be the combined data of the first three-dimensional point cloud data and the second three-dimensional point cloud data (a three-dimensional model without texture), or the combined data with texture added (a three-dimensional model with texture).
In addition, the display mode of the three-dimensional model illustrated in Figure 4 is one specific example, and it may be possible to rotate the three-dimensional model to view the shape of the bridge HB from various angles, or to display the three-dimensional model in a manner that cuts it at an arbitrary cross-section (for example, the cross-section indicated by the dashed line TS in Figure 4) to view its cross-sectional shape.

The three-dimensional model generated as described above reproduces the shape of the bridge HB with high precision, making it possible to measure the dimensions of the bridge HB in detail without removing the bridge HB deck FS.

<Modification>
The above-described embodiment is not limited to the above description, and various modifications and improvements are possible.

The three-dimensional model generation system according to the present invention is not limited to the configuration shown in FIG. 1, and configurations may be omitted or configurations not shown may be added within the scope of achieving the object of the present invention.

The procedure of the flowchart shown in FIG. 3 may have some steps omitted or steps not shown added within the scope of achieving the object of the present invention.

The shape and movement control of the robot 110 used in implementing the present invention are not limited to the aspects described in the above embodiment, and can be modified as appropriate within the scope of achieving the object of the present invention.

In the above embodiment, the embodiment of the present invention has been exemplified in a situation where the target markers arranged in the scanning range by the laser scanner 120 and the target markers arranged in the shooting range by the camera 140 are different from each other (there are no overlapping target markers), but the implementation of the present invention is not limited to this. That is, in a situation where the above-mentioned scanning range and shooting range are allowed to overlap, and a target marker (hereinafter referred to as a common target marker) arranged at the overlapping position exists, it is preferable to combine the first three-dimensional point cloud data and the second three-dimensional point cloud data with the common target marker as a reference. At this time, it is not necessarily necessary to measure the coordinates of the common target marker in the real space. This is because the first three-dimensional point cloud data and the second three-dimensional point cloud data can be combined with a certain degree of accuracy by mapping the point cloud corresponding to the common target marker included in the first three-dimensional point cloud data and the point cloud corresponding to the common target marker included in the second three-dimensional point cloud data to the same position in the virtual space.
However, even when implementing the present invention using this modified example, it is preferable to measure the coordinates of each target marker in real space and, when combining the first three-dimensional point cloud data and the second three-dimensional point cloud data, reflect the measured coordinates in the mapping of the target markers contained in each three-dimensional point cloud data, and it is preferable to execute a process corresponding to step S120 in Figure 3 (surveying process).

The three-dimensional model generating method according to the above modified example includes a marker placing step of placing a plurality of target markers on the bridge; a scanning step of scanning the bridge with a laser scanner mounted on a robot attached to the underside of the bridge; a photographing step of photographing the bridge with a camera mounted on an aircraft to obtain a plurality of photographed images; a photogrammetry step of generating first three-dimensional point cloud data by a computer based on the plurality of photographed images taken in the photographing step; and a model generating step of generating a three-dimensional model of the bridge by combining the first three-dimensional point cloud data generated in the photogrammetry step with second three-dimensional point cloud data obtained as a result of the scanning in the scanning step. the plurality of target markers arranged in the marker arrangement step include a common target marker arranged at a position where a scanning range scanned by a laser scanner in the scanning step and a photographing range photographed by a camera in the photographing step overlap, and in the model generation step, the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the common target marker included in the first three-dimensional point cloud data and a point cloud corresponding to the common target marker included in the second three-dimensional point cloud data to the same position in a virtual space.
Furthermore, the three-dimensional model generation system according to the above-described modified example can be expressed as a three-dimensional model generation system including a plurality of target markers provided on a bridge, a robot attached to the underside of the bridge, a laser scanner mounted on the robot and scanning the bridge, an aircraft, a camera mounted on the aircraft and photographing the bridge to obtain a plurality of photographed images, and a computer that generates first three-dimensional point cloud data based on the plurality of photographed images taken by the camera, and combines the first three-dimensional point cloud data with second three-dimensional point cloud data obtained as a result of the scanning by the laser scanner to generate a three-dimensional model of the bridge, wherein the plurality of target markers include a common target marker that is arranged at a position where the scan range scanned by the laser scanner and the photographed range photographed by the camera overlap, and the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the common target marker included in the first three-dimensional point cloud data and a point cloud corresponding to the common target marker included in the second three-dimensional point cloud data to the same position in a virtual space.

<Additional Notes>
The present embodiment encompasses the following technical idea.
(1) A three-dimensional model generation method for generating a three-dimensional model of a bridge, the method including: a marker placement step for placing a plurality of target markers on the bridge; a surveying step for measuring coordinates in real space for the plurality of target markers placed in the marker placement step; a scanning step for scanning the bridge with a laser scanner mounted on a robot attached to the underside of the bridge; a photographing step for photographing the bridge with a camera mounted on an aircraft to obtain a plurality of photographed images; a photogrammetry step for a computer to generate first three-dimensional point cloud data based on the plurality of photographed images photographed in the photographing step; and a calculation step for the computer to calculate the first three-dimensional point cloud data generated in the photogrammetry step and a second three-dimensional point cloud data obtained as a result of the scanning in the scanning step. and a model generation process of generating a three-dimensional model of the bridge by combining the first three-dimensional point cloud data and the second three-dimensional point cloud data, wherein the multiple target markers provided on the bridge in the marker placement process are placed in a scan range scanned by the laser scanner in the scanning process and in a photographing range photographed by the camera in the photographing process, respectively, and in the model generation process, the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the target markers included in the first three-dimensional point cloud data and a point cloud corresponding to the target markers included in the second three-dimensional point cloud data into a virtual space based on coordinates measured in the surveying process.
(2) A three-dimensional model generation method for generating a three-dimensional model of a bridge, the method including: a marker placement step of placing a plurality of target markers on the bridge; a scanning step of scanning the bridge with a laser scanner mounted on a robot attached to the underside of the bridge; a photographing step of photographing the bridge with a camera mounted on an aircraft to obtain a plurality of photographed images; a photogrammetry step of generating first three-dimensional point cloud data based on the plurality of photographed images photographed in the photographing step by a computer; and a model generation step of generating a three-dimensional model of the bridge by combining the first three-dimensional point cloud data generated in the photogrammetry step and second three-dimensional point cloud data obtained as a result of the scanning in the scanning step by the computer. and a generating step of generating a three-dimensional model, wherein the plurality of target markers arranged in the marker arrangement step include a common target marker arranged at a position where a scan range scanned by the laser scanner in the scanning step and an imaging range imaged by the camera in the imaging step overlap, and wherein in the model generation step, the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the common target marker included in the first three-dimensional point cloud data and a point cloud corresponding to the common target marker included in the second three-dimensional point cloud data to the same position in a virtual space.
(3) A three-dimensional model generation method as described in (1) or (2), characterized in that the robot used in the scanning process is attached across a first main girder and a second main girder among the multiple main girders that make up the bridge, and the laser scanner mounted on the robot is capable of scanning the space sandwiched between the first main girder and the second main girder.
(4) The three-dimensional model generating method described in (3) is characterized in that the robot used in the scanning process has a mechanism for moving the laser scanner, and the mounted laser scanner can be lowered to a position where it can scan the undersides of the lower flanges of the first main girder and the second main girder.
(5) A three-dimensional model generating method according to (3) or (4), characterized in that the robot used in the scanning process is a mobile robot capable of moving in the bridge axis direction of the bridge, and the scanning process alternately repeats a process in which the robot moves to a predetermined position and a process in which the robot stops at the predetermined position and the laser scanner scans the space between the first main girder and the second main girder.
(6) A three-dimensional model generation method according to any one of (1) to (5), further comprising an output step in which an output means outputs the three-dimensional model generated in the model generation step in a format that is visible to a user.
(7) A three-dimensional model generation system for generating a three-dimensional model of a bridge, the system including: a plurality of target markers provided on the bridge and having coordinates in real space measured; a robot attached to an underside of the bridge; a laser scanner mounted on the robot and scanning the bridge; an aircraft; a camera mounted on the aircraft and photographing the bridge to obtain a plurality of photographed images; and a three-dimensional model generation system for generating first three-dimensional point cloud data based on the plurality of photographed images photographed by the camera, and combining the first three-dimensional point cloud data with second three-dimensional point cloud data obtained as a result of scanning by the laser scanner to generate a three-dimensional model of the bridge. and a computer that generates a three-dimensional model of a beam, wherein the multiple target markers are arranged in a scan range scanned by the laser scanner and in a photographing range photographed by the camera, and the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the target markers included in the first three-dimensional point cloud data and a point cloud corresponding to the target markers included in the second three-dimensional point cloud data into a virtual space based on surveyed coordinates.
(8) A three-dimensional model generation system for generating a three-dimensional model of a bridge, comprising: a plurality of target markers provided on the bridge; a robot attached to an underside of the bridge; a laser scanner mounted on the robot for scanning the bridge; an aircraft; a camera mounted on the aircraft for photographing the bridge to obtain a plurality of photographed images; and a computer for generating first three-dimensional point cloud data based on the plurality of photographed images photographed by the camera, and for combining the first three-dimensional point cloud data with second three-dimensional point cloud data obtained as a result of scanning by the laser scanner to generate the three-dimensional model of the bridge. and a computer that maps a point cloud corresponding to the common target marker included in the first three-dimensional point cloud data and a point cloud corresponding to the common target marker included in the second three-dimensional point cloud data to the same position in a virtual space, wherein the plurality of target markers include a common target marker that is arranged at a position where a scan range scanned by the laser scanner and a capture range captured by the camera overlap, and the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the common target marker included in the first three-dimensional point cloud data and a point cloud corresponding to the common target marker included in the second three-dimensional point cloud data to the same position in a virtual space.

100 Three-dimensional model generation system 110 Robot 111, 112 Suspended cart 113 Mechanism unit 120 Laser scanner 130 Aircraft 140 Camera 150 Computer HB Bridge MG1 to MG4 Main girder FS Deck GF Wall parapet P Paving surface TM1 to TM7 Target marker

Claims (6)

A three-dimensional model generation method for generating a three-dimensional model of a bridge, comprising the steps of:
a marker placement step of placing a plurality of target markers on the bridge;
a surveying step of surveying coordinates in real space of the plurality of target markers arranged in the marker arrangement step;
a scanning step of scanning the bridge with a laser scanner mounted on a robot attached to the underside of the bridge;
A photographing step in which a camera mounted on a drone photographs the bridge to obtain a plurality of photographed images;
a photogrammetry process in which a computer generates first three-dimensional point cloud data based on the plurality of captured images captured in the photographing process;
a model generation process in which the computer generates a three-dimensional model of the bridge by combining the first three-dimensional point cloud data generated in the photogrammetry process and second three-dimensional point cloud data obtained as a result of the scanning in the scanning process;
Equipped with
the plurality of target markers provided on the bridge in the marker placement step are arranged in a scan range scanned by the laser scanner in the scanning step and in a photographing range photographed by the camera in the photographing step,
In the model generation step, the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the target marker included in the first three-dimensional point cloud data and a point cloud corresponding to the target marker included in the second three-dimensional point cloud data onto a virtual space based on coordinates measured in the surveying step.
A three-dimensional model generating method comprising: The robot used in the scanning process is attached across a first main girder and a second main girder among a plurality of main girders constituting the bridge,
The laser scanner mounted on the robot is capable of scanning a space between the first main girder and the second main girder.
2. The three-dimensional model generating method according to claim 1 . The robot used in the scanning process is
A mechanism for moving the laser scanner is provided.
The laser scanner can be lowered to a position where the mounted laser scanner can scan the lower surfaces of the lower flanges of the first main girder and the second main girder.
3. The three-dimensional model generating method according to claim 2 . The robot used in the scanning process is a mobile robot that can move in the bridge axis direction of the bridge,
The scanning step includes:
the robot moving to a predetermined position;
a step of the robot being stationary at the predetermined position and the laser scanner scanning a space between the first main girder and the second main girder;
Repeat alternately.
4. The three-dimensional model generating method according to claim 2 or 3 . an output step of outputting the three-dimensional model generated in the model generation step in a format that can be viewed by a user by an output means;
The three-dimensional model generating method according to any one of claims 1 to 4 . A three-dimensional model generation system for generating a three-dimensional model of a bridge, comprising:
A plurality of target markers are provided on the bridge, and the coordinates of the target markers in real space are measured.
A robot attached to the underside of the bridge;
A laser scanner mounted on the robot for scanning the bridge;
Drones and
A camera mounted on the drone and adapted to photograph the bridge and obtain a plurality of photographed images;
a computer that generates first three-dimensional point cloud data based on the plurality of captured images captured by the camera, and combines the first three-dimensional point cloud data with second three-dimensional point cloud data obtained as a result of scanning by the laser scanner to generate a three-dimensional model of the bridge;
Equipped with
the plurality of target markers are arranged in a scanning range scanned by the laser scanner and in a photographing range photographed by the camera,
the computer combines the first three-dimensional point cloud data and the second three-dimensional point cloud data by mapping a point cloud corresponding to the target marker included in the first three-dimensional point cloud data and a point cloud corresponding to the target marker included in the second three-dimensional point cloud data onto a virtual space based on surveyed coordinates;
A three-dimensional model generation system comprising:

Images