Ortho-image creation method, ortho-image creation system, three-dimensional model creation method, and three-dimensional model creation system

Abstract

To provide a method and an apparatus for easily surveying a road condition on the basis of photographed images photographed from the sky even when there is an obstacle that partially covers a road surface when viewed from the sky.SOLUTION: An ortho-image creation method includes: a first photographing step of photographing a road, a road surface of which is partially covered by an obstacle when viewed from the sky, from an altitude higher than the obstacle to obtain a plurality of first photographed images; a second photographing step of photographing an area covered by the obstacle from an altitude lower than the obstacle to obtain a plurality of second photographed images; a first coordinate acquisition step of acquiring three-dimensional coordinates of a first feature point located outside the area covered by the obstacle and included in the plurality of first photographed images; a second coordinate acquisition step of acquiring three-dimensional coordinates of a second feature point located in the area covered by the obstacle and included in the plurality of second photographed images; and an ortho-image creation step of, on the basis of them, correcting the area covered by the obstacle on the road surface to an area not covered by the obstacle.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an orthoimage creation method for creating orthoimages based on images taken from the sky by, for example, an unmanned aerial vehicle, an orthoimage creation system, a three-dimensional model creation method, a three-dimensional model creation system, and signs used therein. [Background technology]

[0002] Conventionally, when damage such as cracks occurs on the surface of the asphalt pavement that forms the surface layer of a road, the road needs to be repaired.

[0003] To repair a road, various investigations are conducted, such as investigating the road condition (e.g., crack condition) at the time of starting repair work and the positions of planar elements including road edges and lane markings. Conventionally, for example, crack condition investigations have been conducted by inspectors visually investigating the locations and amount of cracks on the road. Instead of inspectors detecting cracks, road conditions have sometimes been investigated using a dedicated road surface property measurement vehicle (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-123510 Summary of the Invention [Problem to be solved by the invention]

[0005] The work of inspectors inspecting roads and detecting cracks is extremely tedious. When investigating road conditions using a dedicated road surface property measurement vehicle, the vehicle must be driven, but on narrow roads, the vehicle cannot be driven, making it impossible to inspect the road condition.

[0006] In order to solve the above-mentioned technical issues, it is conceivable to photograph the road using an unmanned aerial vehicle flying overhead when repair work begins, create an orthoimage of the road at the time of repair work beginning based on the photographed image, and detect cracks on the road surface from the orthoimage.

[0007] However, if an obstacle, for example, a roadside tree, is present near the road and covers the widthwise edge of the road surface, even if an unmanned aerial vehicle flying overhead photographs the road surface, it is impossible to capture the portion of the road surface covered by the obstacle. Therefore, it is impossible to create an orthoimage that includes the entire road surface, and it is impossible to investigate cracks on the road surface covered by the obstacle. Furthermore, if an obstacle covers the widthwise edge of the road surface, even if an unmanned aerial vehicle flying overhead photographs the road surface, it is impossible to capture the portion of the road surface covered by the obstacle. Therefore, it is impossible to investigate the width of the road (the position of the road edge) or the position of planar elements, including lane markings and other dividing lines. Note that, when a road is photographed by an unmanned aerial vehicle flying overhead, other obstacles similar to the above-mentioned obstacles include, for example, pedestrian bridges and traffic lights located above the road surface.

[0008] The present invention has been made with an eye on such problems, and aims to provide an orthoimage creation method, an orthoimage creation system and signs used therein, a 3D model creation method, a 3D model creation system and signs used therein, which make it possible to easily investigate the road condition at the time of starting repair work based on images taken from the air, even if there is an obstacle covering part of the road surface. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention takes the following measures.

[0010] That is, the orthoimage creation method according to the present invention includes a first photographing step of photographing a road in which a part of the road surface is covered by an obstacle when viewed from above with a first photographing device from an altitude higher than the obstacle to obtain a plurality of first photographed images; a second photographing step of photographing an area covered by the obstacle with a second photographing device from an altitude lower than the obstacle to obtain a plurality of second photographed images; a first coordinate acquisition step of acquiring three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and that is included in at least two of the plurality of first photographed images; The method is characterized by comprising a second coordinate acquisition step of acquiring three-dimensional coordinates of second feature points included in the plurality of second photographed images, and an orthoimage creation step of creating a corrected orthoimage in which at least a portion of the area of ​​the road surface covered by the obstacle is corrected to an area not covered by the obstacle, based on the plurality of first photographed images photographed in the first photographing step, the plurality of second photographed images photographed in the second photographing step, the three-dimensional coordinates of the first feature points acquired in the first coordinate acquisition step, and the three-dimensional coordinates of the second feature points acquired in the second coordinate acquisition step.

[0011] The orthoimage creation system according to the present invention includes a first image storage means for storing a plurality of first photographed images of a road in which a part of the road surface is covered by an obstacle when viewed from above, the first photographed images being taken by a first photographing device from an altitude higher than the obstacle; a second photographed image storage means for storing a plurality of second photographed images of an area covered by the obstacle, the second photographed images being taken by a second photographing device from an altitude lower than the obstacle; a first coordinate storage means for storing three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and that is included in at least two of the plurality of first photographed images; and an orthoimage creation means for creating a corrected orthoimage in which at least a portion of an area of ​​the road surface covered by the obstacle is corrected to an area not covered by the obstacle, based on the plurality of first photographed images stored in the first photographed image storage means, the plurality of second photographed images stored in the second photographed image storage means, the three-dimensional coordinates of the first feature points stored in the first coordinate storage means, and the three-dimensional coordinates of the second feature points stored in the second storage means.

[0012] As a result, with the orthoimage creation method and orthoimage creation system according to the present invention, even if a part of the road surface is covered by an obstacle when viewed from above, it is possible to create a corrected orthoimage in which the area of ​​the road surface covered by the obstacle is corrected to an area not covered by the obstacle. Therefore, even if there is an obstacle covering part of the road surface, it is possible to easily investigate the road condition at the time of starting repair work based on the image taken from above.

[0013] In the orthoimage creation method of the present invention, the orthoimage creation step is characterized in that it includes a first orthoimage creation step of creating a provisional orthoimage in which a portion of the road surface is covered by the obstacle based on a plurality of first photographed images taken in the first photographing step and the three-dimensional coordinates of the first feature points acquired in the first coordinate acquisition step; a shape detection step of detecting the shape of at least a portion of the road surface and parts other than the road surface in the area covered by the obstacle based on a plurality of second photographed images taken in the second photographing step and the three-dimensional coordinates of the second feature points acquired in the second landmark acquisition step; and a second orthoimage creation step of creating the corrected orthoimage in which at least a portion of the area covered by the obstacle in the provisional orthoimage created in the first orthoimage creation step is corrected to an area not covered by the obstacle.

[0014] In the orthoimage creation system of the present invention, the orthoimage creation means is characterized by comprising: a first orthoimage creation means that creates a provisional orthoimage in which a portion of the road surface is covered by an obstacle based on a plurality of first photographed images stored in the first image storage means and the three-dimensional coordinates of the first feature points stored in the first coordinate storage means; a shape detection means that detects the shape of at least a portion of the road surface and parts other than the road surface in the area covered by the obstacle based on a plurality of second photographed images stored in the second photographed storage means and the three-dimensional coordinates of the second feature points stored in the second coordinate storage means; and a second orthoimage creation means that creates the corrected orthoimage in which at least a portion of the area covered by the obstacle in the provisional orthoimage created by the first orthoimage creation means is corrected to an area not covered by the obstacle.

[0015] As a result, with the orthoimage creation method and orthoimage creation system according to the present invention, even if part of the road surface is covered by an obstacle when viewed from above, it is possible to create a corrected orthoimage in which the area of ​​the road surface in the provisional orthoimage that is covered by the obstacle is corrected to an area that is not covered by the obstacle. Therefore, even if there is an obstacle covering part of the road surface, it is possible to easily investigate the road condition at the time of starting repair work based on the image taken from above.

[0016] In the orthoimage creation method of the present invention, the first photographing device is an unmanned aerial vehicle or a model aircraft flying at an altitude higher than the obstacle, and the second photographing device is an unmanned aerial vehicle or a model aircraft flying at an altitude lower than the obstacle, or a camera positioned at an altitude lower than the obstacle.

[0017] In the orthoimage creation system of the present invention, the first photographing device is an unmanned aerial vehicle or a model aircraft flying at an altitude higher than the obstacle, and the second photographing device is an unmanned aerial vehicle or a model aircraft flying at an altitude lower than the obstacle, or a camera positioned at an altitude lower than the obstacle.

[0018] As a result, the orthoimage creation method and orthoimage creation system of the present invention make it possible to easily obtain a plurality of first photographed images of a road surface not covered by obstacles taken from an altitude higher than the obstacles using an unmanned aerial vehicle or a model aircraft, and a plurality of second photographed images of a road surface covered by obstacles taken from an altitude lower than the obstacles.

[0019] In the orthoimage creation method of the present invention, the second photographing step is characterized in that a plurality of signs are installed on the road surface and on the obstacles in the area covered by the obstacles, and the plurality of signs are photographed so as to be included as the second feature points in at least two of the second photographed images.

[0020] In the orthoimage creation system of the present invention, the plurality of second photographed images stored in the second photographed image storage means are characterized in that they are photographed so that a plurality of signs installed on the road surface and the obstacles in the area covered by the obstacles are included as the second feature points in at least two of the second photographed images.

[0021] As a result, the orthoimage creation method and orthoimage creation system of the present invention make it possible to accurately grasp the shape of the road surface and obstacles in areas covered by the obstacles using multiple second captured images taken from an altitude lower than the obstacles.

[0022] The sign according to the present invention is used in the orthoimage creation method according to the present invention, and is characterized in that it is in the form of a sticker with an adhesive layer formed on the back side, which makes it possible to easily fix the sign to the installation location.

[0023] The sign according to the present invention is used in the orthoimage creation system according to the present invention, and is characterized in that it is in the form of a sticker with an adhesive layer formed on the back side, which makes it possible to easily fix the sign to the installation location.

[0024] The three-dimensional model creation method according to the present invention includes a first photographing step of photographing a road, the road surface of which is partially covered by an obstacle when viewed from above, with a first photographing device from an altitude higher than the obstacle to obtain a plurality of first photographed images; a second photographing step of photographing an area covered by the obstacle with a second photographing device from an altitude lower than the obstacle to obtain a plurality of second photographed images; a first coordinate acquisition step of acquiring three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and that is included in at least two of the plurality of first photographed images; and a 3D model creation step of creating a corrected 3D model in which at least a part of the area of ​​the road surface covered by the obstacle is corrected to an area not covered by the obstacle, based on the plurality of first photographed images photographed in the first photographing step, the plurality of second photographed images photographed in the second photographing step, the 3D coordinates of the first feature points acquired in the first coordinate acquisition step, and the 3D coordinates of the second feature points acquired in the second coordinate acquisition step.

[0025] The three-dimensional model creation system according to the present invention includes a first photographed image storage means for storing a plurality of first photographed images of a road in which a part of the road surface is covered by an obstacle when viewed from above, the first photographed image being taken by a first photographing device from an altitude higher than the obstacle; a second photographed image storage means for storing a plurality of second photographed images of an area covered by the obstacle, the second photographed image being taken by a second photographing device from an altitude lower than the obstacle; a first coordinate storage means for storing three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and that is included in at least two of the plurality of first photographed images; The system is characterized by comprising a second coordinate storage means for storing three-dimensional coordinates of second feature points included in at least two of the plurality of second photographed images, and a three-dimensional model creation means for creating a corrected three-dimensional model in which at least a portion of the area covered by the obstacle on the road surface is corrected to an area not covered by the obstacle, based on the plurality of first photographed images stored in the first photographed image storage means, the plurality of second photographed images stored in the second photographed image storage means, the three-dimensional coordinates of the first feature points stored in the first coordinate storage means, and the three-dimensional coordinates of the second feature points stored in the second coordinate storage means.

[0026] As a result, with the 3D model creation method and 3D model creation system according to the present invention, even if part of the road surface is covered by an obstacle when viewed from above, it is possible to create a corrected 3D model in which the area of ​​the road surface covered by the obstacle is corrected to an area not covered by the obstacle. Therefore, even if there is an obstacle covering part of the road surface, it is possible to investigate the width of the road (the position of the road edge) at the time of starting repair work and the positions of planar elements including lane markings and other dividing lines based on images taken from above.

[0027] In the 3D model creation method of the present invention, the 3D model creation step is characterized by comprising: a first creation step of creating a temporary 3D model in which a portion of the road surface is covered by the obstacle based on a plurality of first captured images taken in the first photographing step and the 3D coordinates of the first feature points acquired in the first coordinate acquisition step; a shape detection step of detecting the shape of the road surface and at least a portion of the portion other than the road surface in the area covered by the obstacle based on a plurality of second captured images taken in the second photographing step and the 3D coordinates of the second feature points acquired in the second landmark acquisition step; and a second 3D model creation step of creating the corrected 3D model in which at least a portion of the area covered by the obstacle of the temporary 3D model created in the first creation step is corrected to an area not covered by the obstacle.

[0028] In the 3D model creation system of the present invention, the 3D model creation means comprises: a first 3D model creation means that creates a temporary 3D model in which a portion of the road surface is covered by the obstacle based on a plurality of first captured images stored in the first captured image storage means and the 3D coordinates of the first feature points stored in the first coordinate storage means; a shape detection means that detects the shape of the road surface and at least a portion of the portion other than the road surface in the area covered by the obstacle based on a plurality of second captured images stored in the second captured image storage means and the 3D coordinates of the second feature points stored in the second coordinate storage means; and a second 3D model creation means that creates the corrected 3D model in which at least a portion of the area covered by the obstacle of the temporary 3D model created by the first 3D model creation means is corrected to an area not covered by the obstacle.

[0029] As a result, with the 3D model creation method and 3D model creation system according to the present invention, even if part of the road surface is covered by an obstacle when viewed from above, it is possible to create a corrected 3D model in which the area of ​​the road surface in the temporary 3D model that is covered by the obstacle is corrected to an area that is not covered by the obstacle. Therefore, even if there is an obstacle covering part of the road surface, it is possible to investigate the width of the road (the position of the road edge) at the time of starting repair work and the positions of planar elements including lane markings and other dividing lines based on images taken from above.

[0030] In the three-dimensional model creation method of the present invention, the first image capturing device is an unmanned aerial vehicle or a model aircraft flying at an altitude higher than the obstacle, and the second image capturing device is an unmanned aerial vehicle or a model aircraft flying at an altitude lower than the obstacle, or a camera positioned at an altitude lower than the obstacle.

[0031] In the three-dimensional model creation system of the present invention, the first image capturing device is an unmanned aerial vehicle or a model aircraft flying at an altitude higher than the obstacle, and the second image capturing device is an unmanned aerial vehicle or a model aircraft flying at an altitude lower than the obstacle, or a camera positioned at an altitude lower than the obstacle.

[0032] As a result, the 3D model creation method and 3D model creation system of the present invention can easily obtain a plurality of first photographed images of a road surface not covered by obstacles taken from an altitude higher than the obstacles using an unmanned aerial vehicle or a model aerial vehicle, and a plurality of second photographed images of a road surface covered by obstacles taken from an altitude lower than the obstacles.

[0033] In the three-dimensional model creation method according to the present invention, in the second photographing step, a plurality of signs are placed on the road surface and on the obstacles in the area covered by the obstacles, and the plurality of signs are photographed so as to be included in at least two of the second photographed images as the second feature points.

[0034] In the three-dimensional model creation system of the present invention, the plurality of second photographed images stored in the second photographed image storage means are characterized in that they are photographed so that a plurality of signs installed on the road surface and on the obstacles in the area covered by the obstacles are included as the second feature points in at least two of the second photographed images.

[0035] As a result, the 3D model creation method and 3D model creation system of the present invention make it possible to accurately grasp the shape of the road surface and obstacles in areas covered by the obstacles by using multiple second captured images taken from an altitude lower than the obstacles.

[0036] The sign according to the present invention is used in the three-dimensional model creation method according to the present invention, and is characterized in that it is in the form of a sticker with an adhesive layer formed on the back side, which makes it possible to easily fix the sign to the installation location.

[0037] The sign according to the present invention is a sign used in the 3D model creation system according to the present invention, and is characterized in that it is in the form of a sticker with an adhesive layer formed on the backside, which makes it possible to easily fix the sign to the installation location. [Effects of the Invention]

[0038] As described above, according to the present invention, even if there is an obstacle covering part of the road surface, it is possible to easily inspect the road condition at the time of starting repair work based on images taken from the air. [Brief explanation of the drawings]

[0039] [Figure 1] 1 is a diagram showing a schematic configuration of an orthoimage creation system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram showing a state in which a plurality of anti-aircraft signs are installed near both ends of a road when the road is photographed from above. [Figure 3] FIG. [Figure 4] FIG. 10 is a diagram illustrating a state in which an anti-aircraft marker is included in two captured images. [Figure 5] FIG. 1 is a diagram illustrating a method for creating an orthoimage in an orthoimage creation device. [Figure 6] FIG. 1 illustrates a UAV flying at a higher altitude than an obstacle. [Figure 7] FIG. 10 is a diagram showing a provisional orthoimage created based on images taken by a UAV flying at a higher altitude than an obstacle. [Figure 8] FIG. 10 is a diagram showing the installation of an anti-aircraft marker in an area covered with obstacles. [Figure 9] FIG. 1 illustrates a UAV flying at a lower altitude than an obstacle. [Figure 10] FIG. 10 is a diagram showing a corrected orthoimage created by removing obstacles from the temporary orthoimage. [Figure 11] 10A and 10B are diagrams illustrating differences in the areas that are stereoscopically rendered in the provisional orthoimage and the corrected orthoimage. [Figure 12] FIG. 1 is an enlarged view of a road surface on which cracks have formed. [Figure 13] FIG. 1 is an enlarged view of a road surface on which cracks have formed. [Figure 14] 1 is a diagram showing a schematic configuration of a three-dimensional model creation system according to an embodiment of the present invention. [Figure 15] 1A to 1C are diagrams illustrating a method for creating a three-dimensional model in a three-dimensional model creation device. [Figure 16] This is a 3D model of the road surface when photographed from above. [Figure 17] This is a 3D model of the road surface when photographed from above. [Figure 18] This is a 3D model of the road surface showing the state where obstacles have been removed from the 3D model in Figure 16. [Figure 19] This is a 3D model of the road surface showing the state where obstacles have been removed from the 3D model in Figure 17. [Figure 20]This is a 3D model of the road surface when photographed from above. [Figure 21] This is a 3D model of the road surface showing the state after removing obstacles from the 3D model in Figure 20. [Figure 22] FIG. 10 is a diagram showing a schematic configuration of an orthoimage creation system according to a modified example of the present invention. [Figure 23] 10A and 10B are diagrams illustrating the operation of taking a photograph with a camera placed at a lower altitude than an obstacle. DETAILED DESCRIPTION OF THE INVENTION

[0040] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a case will be described in which there are roadside trees that act as obstacles around a road, and when the road and its surroundings are photographed from above, part of the road surface is covered by the roadside trees.

[0041] An orthoimage creation system 1 according to an embodiment of the present invention includes a total station 2 installed at a known point (e.g., a reference point), a UAV3 (Unmanned Aerial Vehicle) which is an unmanned aerial vehicle used as an imaging device, and an orthoimage creation device 10 to which the total station 2 and UAV3 are wirelessly connected.

[0042] The total station 2 emits distance measurement light toward each point on the road surface, receives the light reflected at each point, and acquires the three-dimensional coordinates of each point relative to a known point based on the number of times the light wave oscillates from emission to reception, and supplies the three-dimensional coordinates to the orthoimage creation system 10. In this embodiment, the total station 2 is used to acquire the three-dimensional coordinates of multiple anti-aircraft signs 6.

[0043] The UAV 3 has an imaging device, photographs the road surface from the sky, acquires imaging data, and supplies the imaging data to the orthoimage creation device 10. The UAV 3 can photograph while flying at an altitude higher than obstacles, and can also photograph while flying at an altitude lower than obstacles.

[0044] The orthoimage creation device 10 is composed of, for example, a microcomputer, and is equipped with a CPU, a ROM storing a program that controls the operation of the orthoimage creation device 10, and a RAM in which data used when executing the program is temporarily stored.

[0045] As shown in FIG. 1, the orthoimage creation device 10 has a coordinate storage unit 11, a captured image storage unit 12, an orthoimage creation unit 13, a shape detection unit 14, and a display control unit 15. The coordinate storage unit 11 has a first coordinate storage unit 11a and a second coordinate storage unit 11b. The captured image storage unit 12 has a first captured image storage unit 12a and a second captured image storage unit 12b. The orthoimage creation unit 13 has a first orthoimage creation unit 13a and a second orthoimage creation unit 13b. The orthoimage creation device 10 also has a display unit 5 such as a display screen.

[0046] The coordinate storage unit 11 separately stores three-dimensional coordinates of feature points such as a plurality of anti-aircraft markers 6 acquired by the total station 2. The first coordinate storage unit 11a stores three-dimensional coordinates of anti-aircraft markers 6 (first feature points) installed in areas other than those covered by obstacles when photographed by a UAV 3 flying at a higher altitude than obstacles covering part of the road surface. The second coordinate storage unit 11b stores three-dimensional coordinates of anti-aircraft markers 6 (second feature points) installed in areas covered by obstacles when photographed by a UAV 3 flying at a lower altitude than obstacles covering part of the road surface.

[0047] The captured image storage unit 12 stores a plurality of images of a road taken from above by a UAV 3 flying at a substantially constant altitude above the road. The first captured image storage unit 12a stores a plurality of first captured images of a road in which a portion of the road surface is covered by an obstacle when viewed from above, taken from an altitude higher than the obstacle. The second captured image storage unit 12b stores a plurality of second captured images of an area covered by the obstacle, taken from an altitude lower than the obstacle.

[0048] In this embodiment, the UAV 3 flies at an altitude of 20 meters or less above the ground during photography, for example, at an altitude of 3 to 20 meters, and preferably at an altitude of 3 to 15 meters.

[0049] Obstacles around the road that cover part of the road surface when viewed from above are, for example, about 3 to 10 meters high. Therefore, when photographing at an altitude higher than the obstacles, the UAV 3 flies at an altitude of, for example, 10 to 20 meters above ground, and when photographing at an altitude lower than the obstacles, the UAV 3 flies at an altitude of, for example, 3 to 10 meters above ground.

[0050] When photographing a road using a UAV 3 flying at a higher altitude than obstacles, as shown in FIG. 2, multiple anti-aircraft markers 6 are installed as multiple feature points near both ends of the road, for example. The multiple anti-aircraft markers 6 are installed in areas not covered by obstacles, and are installed at intervals of, for example, 5 to 15 meters along the edges of the road (longitudinal direction of the road). The multiple anti-aircraft markers 6 are installed with consideration given to creating an orthoimage by connecting multiple photographed images taken from the sky. The anti-aircraft markers 6 are feature points for which three-dimensional coordinates are provided, and are used as assessment points. Note that when connecting multiple photographed images to create an orthoimage, feature points other than the anti-aircraft markers 6 that are included in the multiple photographed images but for which three-dimensional coordinates are not provided may also be used.

[0051] As shown in FIG. 3, the anti-aircraft sign 6 is a square plate-like member. The anti-aircraft sign 6 has a pattern that clearly identifies its center position. The anti-aircraft sign 6 has an adhesive layer formed on its back surface, and is in the form of a sticker with a backing paper attached to cover the adhesive layer. By removing the backing paper and attaching the sign to the road, it can be easily fixed to the installation location. Therefore, when using the anti-aircraft sign 6, the backing paper covering the adhesive layer is removed and the back side of the anti-aircraft sign 6 is attached to the road surface. The anti-aircraft sign 6 of this embodiment is, for example, a 9 cm x 9 cm square, but the type, shape, size, pattern, etc. of the anti-aircraft sign 6 are not limited thereto.

[0052] As shown in Fig. 4, multiple images taken by a UAV 3 flying at a higher altitude than obstacles are taken so that each anti-aircraft sign 6 is included in at least two of the images. Therefore, at least one common anti-aircraft sign 6 is captured in two adjacent images. Note that Fig. 4 illustrates a case where an anti-aircraft sign 6 is included in all of the images taken, but multiple images taken by a UAV 3 may be taken so that either an anti-aircraft sign 6 or a feature point other than the anti-aircraft sign 6 is included in at least two of the images taken.

[0053] When the anti-aircraft markings 6 are photographed by a UAV 3 flying at a higher altitude than an obstacle covering a portion of the road surface, they are installed outside the area covered by the obstacle, as shown in Figure 2. On the other hand, when the anti-aircraft markings 6 are photographed by a UAV 3 flying at a lower altitude than an obstacle covering a portion of the road surface, they are installed on the road surface or on a portion of the obstacle in the area covered by the obstacle, as shown in Figure 8.

[0054] The orthoimage creation unit 13 creates an orthoimage based on the three-dimensional coordinates of the anti-aircraft markers 6 stored in the coordinate memory unit 11 and the multiple captured images stored in the captured image memory unit 12. Specifically, the orthoimage creation unit 13 performs SfM (Structure from Motion) analysis or the like on the data for the multiple captured images to connect two adjacent captured images based on the common anti-aircraft markers 6 captured in those images, create a three-dimensional model based on the three-dimensional data (point cloud data), and create an orthoimage based on the three-dimensional model.

[0055] More specifically, the first orthoimage creation unit 13a creates a provisional orthoimage based on the plurality of first photographed images stored in the first image storage unit 12a and the three-dimensional coordinates of the anti-aircraft signs 6 installed outside the area covered by the obstacles stored in the first coordinate storage unit 11a. In the provisional orthoimage, a part of the road surface is covered by the obstacles.

[0056] The second orthoimage creation unit 13b creates a corrected orthoimage based on the provisional orthoimage created by the first orthoimage creation unit 13a and the shapes (3D shapes) of the road surface and parts other than the road surface (including the obstacles) in the area covered by the obstacles detected by the shape detection unit 14. Specifically, the second orthoimage creation unit 13b specifies a predetermined range including the area covered by the obstacles in the provisional orthoimage and replaces the predetermined range with the shape (mesh data) detected by the shape detection unit 14 to create a corrected orthoimage in which the area covered by the obstacles is corrected to an area not covered by the obstacles. In the method for creating a corrected orthoimage of this embodiment, a provisional orthoimage is used as a background, a correction orthoimage (mesh data → orthoimage) is created on that background, and the correction orthoimage is integrated with the provisional orthoimage to create a corrected orthoimage (the orthoimages are ultimately integrated). Therefore, the integration method for creating a corrected orthoimage of this embodiment corresponds to the integration method 3 for creating a corrected orthoimage described later.

[0057] The shape detection unit 14 creates mesh data corresponding to the shape (three-dimensional shape) of the road surface and parts other than the road surface (including obstacles) in the area covered by obstacles based on the multiple second photographed images stored in the second photographing memory unit 12b and the three-dimensional coordinates of the anti-aircraft signs 6 installed in the area covered by obstacles stored in the second coordinate memory unit 11b.

[0058] The display control unit 15 displays the orthoimage created by the orthoimage creating unit 13 on the display unit 5 .

[0059] (Creating orthoimages) A method for creating an orthoimage in the orthoimage creation device 10 will be described with reference to Fig. 5. In this embodiment, a method for creating an orthoimage of a road in which the road surface is not covered by obstacles when there are obstacles around the road and part of the road surface is covered by the obstacles when viewed from above will be described.

[0060] In step S1 (first coordinate acquisition step), the total station 2 acquires three-dimensional coordinates, i.e., planar positions (latitude, longitude) and altitude (height), for multiple predetermined positions around the repair area where road repairs are to be performed, i.e., predetermined positions where multiple anti-aircraft signs 6 are to be installed.

[0061] In step S2 (first photographing step), as shown in FIGS. 6(a) and 6(b), a road is photographed from above by a UAV 3 flying at an altitude higher than obstacles T around the road. FIG. 6(b) shows an example of the trajectory of the UAV 3. When photographing, a plurality of anti-aircraft markers 6 are installed in advance at a plurality of predetermined positions surveyed in step S1. Therefore, a plurality of photographed images are taken of the plurality of anti-aircraft markers 6 so that each anti-aircraft marker 6 is included in at least two photographed images.

[0062] In step S3 (first orthoimage creation step), a provisional orthoimage is created based on the three-dimensional coordinates acquired in step S1 and the multiple captured images taken in step S2. In the provisional orthoimage, a part of the road surface is covered by an obstacle T, as shown in FIG.

[0063] In step S4, in an area where part of the road surface is covered by an obstacle T, a plurality of anti-aircraft signs 6 are installed on the road surface and on the side of the obstacle T, which is a part other than the road surface, as shown in Fig. 8. The area covered by the obstacle T is an area that is hidden by the obstacle T when viewed from above. In Fig. 8, the anti-aircraft signs 6 are installed on the side of the obstacle T facing the road.

[0064] In step S5 (second coordinate acquisition step), the total station 2 acquires three-dimensional coordinates, i.e., planar position (latitude, longitude) and altitude (height), for a predetermined position where multiple anti-aircraft signs 6 are installed in an area covered by obstacles T.

[0065] In step S6 (second photographing step), as shown in FIGS. 9(a) and 9(b), the road surface and obstacles T are photographed by the UAV 3 flying at an altitude lower than the obstacles T around the road. FIG. 9(b) shows an example of the flight trajectory of the UAV 3. Therefore, for multiple anti-aircraft signs 6, multiple photographed images are taken so that each anti-aircraft sign 6 is included in at least two photographed images.

[0066] In step S7 (shape detection step), mesh data corresponding to the shape of the road surface and parts other than the road surface (including obstacle T) in the area covered by obstacle T is created based on the multiple second photographed images stored in the second photographing memory unit 12b and the three-dimensional coordinates of the anti-aircraft signs 6 installed in the area covered by obstacle T stored in the coordinate memory unit 11b.

[0067] In step S8 (second orthoimage creation step), a corrected orthoimage in which the road surface is not covered by the obstacle T is created, as shown in Fig. 10, based on the temporary orthoimage created in step S3 and the mesh data corresponding to the shapes of the road surface in the area covered by the obstacle T and the parts other than the road surface (including the obstacle T) created in step S7. In the temporary orthoimage in Fig. 7, part of the road surface is covered by the obstacle T and the road surface in that area is hidden, whereas in the corrected orthoimage in Fig. 10, the obstacle T around the road is cut off near its bottom end and the road surface that was hidden in Fig. 7 is visible.

[0068] In step S9 (display step), the corrected orthoimage in which the road surface is not covered by the obstacle T is displayed on the display unit 5. In this embodiment, the ground pixel size of the orthoimage is 5 mm or less.

[0069] The difference in the regions to be stereoscopically rendered between the provisional orthoimage (FIG. 7) and the corrected orthoimage (FIG. 10) will be described with reference to FIG.

[0070] For example, in a provisional orthoimage created based on images captured by a UAV 3 flying at a higher altitude than an obstacle T around the road, there are no captured images of the area covered by the obstacle T, and therefore the area below the obstacle T cannot be seen, as shown in FIG. 11(a). Even if the obstacle T in FIG. 11(a) is cropped near its bottom edge, as shown in FIG. 11(b), there is no information about the edge of the road surface (the edge on the side closest to the obstacle T), and therefore it is impossible to supplement the edge of the road surface.

[0071] In contrast to this, when the shape (mesh data) of the road surface and the portion other than the road surface (including obstacle T) in the area covered by obstacle T is used, the area below obstacle T is also rendered three-dimensional, as shown in FIG. 11(c). Not all of the area below obstacle T is rendered three-dimensional, but at least the portion near the ground is rendered three-dimensional. Therefore, if obstacle T is cut out near its bottom edge in FIG. 11(c), it is possible to correct the area to one not covered by obstacle T by supplementing the edge of the road surface (the edge on the side closest to obstacle T), as shown in FIG. 11(d).

[0072] (Road survey method using orthoimages) The orthoimages created by the orthoimage creation device 10 as described above are used for various surveys that are carried out when road repairs are carried out.

[0073] For example, using the orthoimages created by the orthoimage creation device 10, (1) investigations into the condition of cracks on the road surface, (2) investigations into the location of planar elements around the road including areas where repairs will be performed, (3) investigations into repairs around manholes, (4) investigations into the distance between two specified points on the road surface, and (5) investigations into the area of ​​a specified range on the road surface are conducted.

[0074] 12 and 13 are enlarged views of a road surface on which cracks have formed. In this way, in the orthoimage created by the orthoimage creation device 10 of this embodiment, it is possible to clearly identify, for example, cracks formed on the road surface. Therefore, based on the orthoimage displayed on the display unit 5, the cracked condition of the road surface is investigated by investigating the locations where cracks have formed on the road surface, including the repair locations where road repairs are to be performed, and the cracking rate and patching rate of those areas.

[0075] As described above, when a part of the road surface is covered by an obstacle when viewed from above, the obstacle is removed and an orthoimage of the road with the road surface not covered by the obstacle is created. In the process of creating the orthoimage, SfM (Structure from Motion) analysis or the like is performed on the data of multiple captured images, and two adjacent captured images are connected based on the common anti-aircraft sign 6 captured in those images to create a 3D model (a 3D model based on 3D data (point cloud data)).

[0076] (Creating a 3D model) A 3D model creation system and a 3D model creation method for creating a 3D model of the periphery of a road will be described with reference to Figures 14 and 15. In this embodiment, a method for creating a 3D model of a road whose surface is not covered by obstacles when there are obstacles around the road and part of the road surface is covered by the obstacles when viewed from above will be described.

[0077] As shown in Figure 14, a three-dimensional model creation system 101 according to an embodiment of the present invention includes a total station 2 installed at a known point (e.g., a reference point), a UAV3 (Unmanned Aerial Vehicle) which is an unmanned aerial vehicle used as an imaging device, and an orthoimage creation device 110 to which the total station 2 and UAV3 are wirelessly connected.

[0078] That is, if the following contents are changed in the orthoimage creation system shown in FIG. 1, a 3D model creation system that creates a 3D model by the 3D model creation method of this embodiment is shown as shown in FIG. The orthoimage creation unit 13 is replaced with a 3D model creation unit 113 that creates a 3D model. The first orthoimage creating unit 13a is replaced with a first creating unit 113a that creates a temporary 3D model. The second orthoimage creating unit 13b is replaced with a second creating unit 113b that creates a corrected three-dimensional model. Moreover, when the following contents are changed in the orthoimage creation method shown in FIG. 5, a 3D model creation method of this embodiment is shown as shown in FIG. · Step S3: Convert the creation of a temporary orthoimage into the creation of a temporary 3D model. Step S8: Convert the creation of the rectified orthoimage into the creation of a rectified 3D model. Step S9: The display of the corrected orthoimage is changed to the display of the corrected 3D model.

[0079] As described above, a corrected orthoimage in which the road surface is not covered by the obstacle T is created based on a provisional orthoimage in which a portion of the road surface is covered by the obstacle T and mesh data corresponding to the shape of the road surface and parts other than the road surface (including the obstacle T) in the area covered by the obstacle T. Similarly, a corrected 3D model in which the road surface is not covered by the obstacle T is created based on a provisional 3D model in which a portion of the road surface is covered by the obstacle T and point cloud data corresponding to the shape of the road surface and parts other than the road surface (including the obstacle T) in the area covered by the obstacle T, and therefore a detailed description thereof will be omitted. Therefore, in the 3D model creation system 101 shown in FIG. 14, the shape detection unit 14 creates point cloud data corresponding to the shape (three-dimensional shape) of the road surface and parts other than the road surface (including the obstacle) in the area covered by the obstacle, based on the plurality of second photographed images stored in the second photographing memory unit 12b and the three-dimensional coordinates of the anti-aircraft signs 6 installed in the area covered by the obstacle stored in the second coordinate memory unit 11b.

[0080] In the method for creating a corrected 3D model of this embodiment, a temporary 3D model is used as a background, a corrective 3D model (mesh data) is created on the background, and the corrective 3D model is then integrated with the temporary 3D model to create the corrected 3D model. Therefore, the integration method for creating a corrected 3D model of this embodiment corresponds to (integration method 1 for creating a corrected 3D model), which will be described later.

[0081] For example, by rotating the 3D model of the road surface on the display screen, it is possible to change it into a 3D model of the road surface viewed from various directions. In the following explanation, the 3D model of the road surface viewed from various directions will be described.

[0082] 16 and 17 are 3D models showing a state in which, when photographing a road surface from above, part of the road surface is covered by obstacles such as roadside trees, traffic lights, and road signs. Therefore, in Figures 16 and 17, part of the road surface is hidden by the obstacles, and that part of the road surface cannot be seen.

[0083] In contrast, Figures 18 and 19 are 3D models showing the state of a road surface photographed from above, with obstacles such as roadside trees, traffic lights, and road signs that cover part of the road surface removed. As a result, parts of the road surface that were hidden by obstacles in Figures 16 and 17 are visible in Figures 18 and 19.

[0084] Fig. 20 is a 3D model created when the road surface is photographed from a different direction than Figs. 16 and 17. In Fig. 20, most of the road surface is hidden by roadside trees. In contrast, Fig. 21 is a 3D model showing the state in which the roadside trees have been removed from Fig. 20. In Fig. 21, most of the road surface that was hidden by roadside trees in Fig. 20 is now visible.

[0085] Therefore, in Figures 18, 19 and 21, the entire road surface is visible, making it possible to investigate the width of the road (position of the road edges) and the position of planar elements including lane markings and other dividing lines.

[0086] The orthoimage creation method of this embodiment includes a first photographing step of photographing a road, the road surface of which is partially covered by an obstacle when viewed from above, using a first photographing device (UAV3) from an altitude higher than the obstacle to obtain a plurality of first photographed images; a second photographing step of photographing an area covered by the obstacle using a second photographing device (UAV3) from an altitude lower than the obstacle to obtain a plurality of second photographed images; a first coordinate acquisition step of acquiring three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and is included in at least two of the plurality of first photographed images; and an orthoimage creation step of creating a corrected orthoimage in which at least a part of an area covered by obstacles on the road surface is corrected to an area not covered by obstacles, based on the first photographed images taken in the first photographing step, the second photographed images taken in the second photographing step, the three-dimensional coordinates of the first feature points acquired in the first coordinate acquisition step, and the three-dimensional coordinates of the second feature points acquired in the second coordinate acquisition step.

[0087] The orthoimage creation system 1 of this embodiment includes a first captured image storage unit 12a that stores a plurality of first captured images of a road in which a part of the road surface is covered by an obstacle when viewed from above, the first captured image storage unit 12a being a first image storage unit (UAV3) that stores a plurality of second captured images of an area covered by the obstacle, the second captured image storage unit 12b being a second image storage unit (UAV3) that stores a plurality of second captured images of an area covered by the obstacle, the second captured image storage unit 12b being a second image storage unit (UAV3) that stores a plurality of second captured images of an area covered by the obstacle, the first coordinate storage unit 11a being a first coordinate storage unit (UAV3) that stores three-dimensional coordinates of first feature points that are located outside the area covered by the obstacle and that are included in at least two of the plurality of first captured images, and and an orthoimage creation unit 13 that creates a corrected orthoimage in which at least a part of the area covered by the obstacles on the road surface is corrected to an area not covered by the obstacles, based on the first captured images stored in the first captured image storage unit 12a, the second captured images stored in the second captured image storage unit 12b, the three-dimensional coordinates of the first feature points stored in the first coordinate storage unit 11a, and the three-dimensional coordinates of the second feature points stored in the second coordinate storage unit 11b.

[0088] As a result, in the orthoimage creation method and orthoimage creation system 1 of this embodiment, even if part of the road surface is covered by an obstacle when viewed from above, it is possible to create a corrected orthoimage in which the area of ​​the road surface covered by the obstacle is corrected to an area not covered by the obstacle. Therefore, even if there is an obstacle covering part of the road surface, it is possible to easily investigate the road condition at the time of starting repair work based on the image taken from above.

[0089] In the orthoimage creation method of this embodiment, the orthoimage creation step includes a first orthoimage creation step of creating a provisional orthoimage in which a portion of the road surface is covered by an obstacle based on a plurality of first photographed images taken in the first photographing step and the three-dimensional coordinates of the first feature points acquired in the first coordinate acquisition step; a shape detection step of detecting the shape of at least a portion of the road surface and portions other than the road surface in the area covered by the obstacle based on a plurality of second photographed images taken in the second photographing step and the three-dimensional coordinates of the second feature points acquired in the second coordinate acquisition step; and a second orthoimage creation step of creating a corrected orthoimage in which at least a portion of the area covered by the obstacles in the provisional orthoimage created in the first orthoimage creation step is corrected to an area not covered by the obstacle.

[0090] In the orthoimage creation system 1 of this embodiment, the orthoimage creation unit 13 includes a first orthoimage creation unit 13a that creates a provisional orthoimage in which part of the road surface is covered by an obstacle based on a plurality of first photographed images stored in a first image memory unit 12a and the three-dimensional coordinates of the first feature points stored in a first coordinate memory unit 11a; a shape detection unit 14 that detects the shape of at least part of the road surface and parts other than the road surface in the area covered by the obstacle based on a plurality of second photographed images stored in a second photographed image memory 12b and the three-dimensional coordinates of the second feature points stored in a second coordinate memory unit 11b; and a second orthoimage creation unit 13b that creates a corrected orthoimage in which at least part of the area covered by the obstacles in the provisional orthoimage created by the first orthoimage creation unit 13a is corrected to an area not covered by the obstacle.

[0091] As a result, with the orthoimage creation method and orthoimage creation system 1 according to the present invention, even if part of the road surface is covered by an obstacle when viewed from above, it is possible to create a corrected orthoimage in which the area of ​​the road surface in the provisional orthoimage that is covered by the obstacle is corrected to an area that is not covered by the obstacle. Therefore, even if there is an obstacle covering part of the road surface, it is possible to easily investigate the road condition at the time of starting repair work based on the image taken from above.

[0092] In the orthoimage creation method of this embodiment, the first imaging device is a UAV 3 that flies at an altitude higher than the obstacles, and the second imaging device is a UAV 3 that flies at an altitude lower than the obstacles.

[0093] In the orthoimage creation system 1 of this embodiment, the first image capturing device is a UAV 3 that flies at an altitude higher than the obstacles, and the second image capturing device is a UAV 3 that flies at an altitude lower than the obstacles. is.

[0094] As a result, in the orthoimage creation method and orthoimage creation system 1 of this embodiment, it is possible to easily obtain, using the UAV 3, a plurality of first photographed images of the road surface not covered by obstacles taken from an altitude higher than the obstacles, and a plurality of second photographed images of the road surface covered by obstacles taken from an altitude lower than the obstacles.

[0095] In the orthoimage creation method of this embodiment, in the second photographing step, multiple anti-aircraft signs 6 are installed on the road surface and on the obstacles in an area covered by obstacles, and the multiple anti-aircraft signs 6 are photographed so that they are included in at least two second photographed images as second feature points.

[0096] In the orthoimage creation system 1 of this embodiment, the multiple second photographed images stored in the second photographed image memory unit 12b are photographed so that multiple anti-aircraft signs 6 installed on the road surface and obstacles in areas covered by obstacles are included in at least two of the second photographed images as second feature points.

[0097] As a result, in the orthoimage creation method and orthoimage creation system 1 of this embodiment, it is possible to accurately grasp the shape of the road surface and obstacles in areas covered by the obstacles by using multiple second captured images taken from an altitude lower than the obstacles.

[0098] The anti-aircraft marker 6 of this embodiment is a marker used in the orthoimage creation method of this embodiment, and is in the form of a sticker with an adhesive layer formed on the back side thereof. This allows the anti-aircraft marker 6 of this embodiment to be easily fixed to the installation location.

[0099] The anti-aircraft marker 6 of this embodiment is a marker used in the orthoimage creation system 1 of this embodiment, and is in the form of a sticker with an adhesive layer formed on the back side thereof. This allows the anti-aircraft marker 6 of this embodiment to be easily fixed to the installation location.

[0100] The three-dimensional model creation method of this embodiment includes a first photographing step of photographing a road, the road surface of which is partially covered by an obstacle when viewed from above, using a first photographing device (UAV3) from an altitude higher than the obstacle to obtain a plurality of first photographed images; a second photographing step of photographing an area covered by the obstacle using a second photographing device (UAV3) from an altitude lower than the obstacle to obtain a plurality of second photographed images; a first coordinate acquisition step of acquiring three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and that is included in at least two of the plurality of first photographed images; and a second coordinate acquisition step of acquiring three-dimensional coordinates of second feature points included in at least two second captured images, and a three-dimensional model creation step of creating a corrected three-dimensional model in which at least a portion of an area covered by obstacles on the road surface is corrected to an area not covered by obstacles, based on the first captured images captured in the first capturing step, the second captured images captured in the second capturing step, the three-dimensional coordinates of the first feature points acquired in the first coordinate acquisition step, and the three-dimensional coordinates of the second feature points acquired in the second coordinate acquisition step.

[0101] The three-dimensional model creation system 101 of this embodiment includes a first captured image storage unit 12a that stores a plurality of first captured images of a road in which a part of the road surface is covered by an obstacle when viewed from above, the first captured image storage unit 12a being a first image storage unit (UAV3) that stores a plurality of second captured images of an area covered by the obstacle, the second captured image storage unit 12b being a second image storage unit (UAV3) that stores a plurality of second captured images of an area covered by the obstacle, the second captured image storage unit 12b being a second image storage unit (UAV3) that stores a plurality of second captured images of an area covered by the obstacle, the first coordinate storage unit 11a being a first coordinate storage unit (UAV3) that stores three-dimensional coordinates of first feature points that are located outside the area covered by the obstacle and that are included in at least two of the plurality of first captured images, and and a 3D model creation unit 113 that creates a corrected 3D model in which at least a part of the area covered by the obstacle on the road surface is corrected to an area not covered by the obstacle, based on the first captured images stored in the first captured image storage unit 12a, the second captured images stored in the second captured image storage unit 12b, the 3D coordinates of the first feature points stored in the first coordinate storage unit 11a, and the 3D coordinates of the second feature points stored in the second coordinate storage unit 11b.

[0102] As a result, in the 3D model creation method and 3D model creation system 101 of this embodiment, even if part of the road surface is covered by an obstacle when viewed from above, it is possible to create a corrected 3D model in which the area of ​​the road surface covered by the obstacle is corrected to an area not covered by the obstacle. Therefore, even if there is an obstacle covering part of the road surface, it is possible to investigate the width of the road (the position of the road edge) at the time of starting repair work and the positions of planar elements including lane markings and other dividing lines based on images captured from above.

[0103] In the 3D model creation method of this embodiment, the 3D model creation step includes a first creation step of creating a temporary 3D model in which a portion of the road surface is covered by an obstacle based on a plurality of first captured images taken in the first capturing step and the 3D coordinates of the first feature points acquired in the first coordinate acquisition step; a shape detection step of detecting the shape of at least a portion of the road surface and portions other than the road surface in the area covered by the obstacle based on a plurality of second captured images taken in the second capturing step and the 3D coordinates of the second feature points acquired in the second target acquisition step; and a second 3D model creation step of creating a corrected 3D model in which at least a portion of the area covered by the obstacle of the temporary 3D model created in the first creation step is corrected to an area not covered by the obstacle.

[0104] In the 3D model creation system 101 of this embodiment, the 3D model creation unit 113 includes a first creation unit 113a that creates a temporary 3D model in which a portion of the road surface is covered by an obstacle based on a plurality of first captured images stored in a first captured image memory unit 12a and the 3D coordinates of first feature points stored in a first coordinate memory unit 11a, a shape detection unit 14 that detects the shape of at least a portion of the road surface and parts other than the road surface in the area covered by the obstacle based on a plurality of second captured images stored in a second captured image memory unit 12b and the 3D coordinates of second feature points stored in a second coordinate memory unit 11b, and a second creation unit 113b that creates a corrected 3D model in which at least a portion of the area covered by the obstacle of the temporary 3D model created by the first creation unit 113a is corrected to an area not covered by the obstacle.

[0105] As a result, with the 3D model creation method and 3D model creation system 101 according to the present invention, even if part of the road surface is covered by an obstacle when viewed from above, it is possible to create a corrected 3D model in which the area of ​​the road surface in the temporary 3D model that is covered by the obstacle is corrected to an area that is not covered by the obstacle. Therefore, even if there is an obstacle covering part of the road surface, it is possible to investigate the width of the road (the position of the road edge) at the time of starting repair work and the positions of planar elements including lane markings and other dividing lines based on images captured from above.

[0106] In the three-dimensional model creation method of this embodiment, the first image capturing device is a UAV 3 that flies at an altitude higher than the obstacles, and the second image capturing device is a UAV 3 that flies at an altitude lower than the obstacles.

[0107] In the three-dimensional model creation system 101 of this embodiment, the first image capturing device is a UAV 3 that flies at an altitude higher than the obstacles, and the second image capturing device is a UAV 3 that flies at an altitude lower than the obstacles.

[0108] As a result, in the 3D model creation method and 3D model creation system 101 of this embodiment, it is possible to easily obtain, by the UAV 3, a plurality of first captured images of the road surface not covered by obstacles taken from an altitude higher than the obstacles, and a plurality of second captured images of the road surface covered by obstacles taken from an altitude lower than the obstacles.

[0109] In the three-dimensional model creation method of this embodiment, in the second photographing step, a plurality of anti-aircraft signs 6 are installed on the road surface and on the obstacles in an area covered by obstacles, and the plurality of anti-aircraft signs 6 are photographed so that they are included in at least two second photographed images as second feature points.

[0110] In the three-dimensional model creation system 101 of this embodiment, the multiple second captured images stored in the second captured image memory unit 12b are captured so that multiple anti-aircraft signs 6 installed on the road surface and obstacles in areas covered by obstacles are included in at least two of the second captured images as second feature points.

[0111] As a result, in the 3D model creation method and 3D model creation system 101 of this embodiment, it is possible to accurately grasp the shape of the road surface and obstacles in areas covered by the obstacles by using multiple second captured images taken from an altitude lower than the obstacles.

[0112] The anti-aircraft marker 6 of this embodiment is a marker used in the 3D model creation method of this embodiment, and is in the form of a sticker with an adhesive layer formed on the back side thereof, which allows the anti-aircraft marker 6 of this embodiment to be easily fixed to the installation location.

[0113] The anti-aircraft sign 6 of this embodiment is a sign used in the three-dimensional model creation system 101 of this embodiment, and is in the form of a sticker with an adhesive layer formed on the back side thereof. This allows the anti-aircraft sign 6 of this embodiment to be easily fixed to the installation location.

[0114] The above describes an embodiment of the present invention, but the specific configuration of each part is not limited to the above-described embodiment, and various modifications are possible within the scope of the spirit of the present invention.

[0115] In the above embodiment, a 3D model and orthoimages are created based on images taken from above a road by a UAV3 flying at a nearly constant altitude of 20 meters or less above the ground, but the present invention includes a method of creating a 3D model and orthoimages based on images taken from above a road by a UAV3 flying at an altitude of more than 20 meters above the ground.

[0116] In the above embodiment, the three-dimensional coordinates of the anti-aircraft signs 6 are acquired by the total station 2, but the three-dimensional coordinates of the anti-aircraft signs 6 may be acquired by, for example, GNSS (Global Navigation Satellite System), which is a positioning system using satellites such as GPS. The three-dimensional coordinates of the anti-aircraft signs 6 may be acquired by scanning with the 3D scanner 4. The three-dimensional coordinates of the anti-aircraft signs 6 installed around the road may be acquired by scanning with the 3D scanner 4. Furthermore, the three-dimensional coordinates of predetermined positions where multiple anti-aircraft signs 6 are installed are acquired by the total station 2, but if the three-dimensional coordinates of the predetermined positions have already been acquired, those three-dimensional coordinates may be acquired instead.

[0117] In the above embodiment, the anti-aircraft marker 6 is square-shaped and has a pattern that clearly identifies the central position used as an evaluation point, but the shape of the anti-aircraft marker 6 and the central position of the anti-aircraft marker 6 are not limited to being characteristic points. The anti-aircraft marker 6 may have a pattern that identifies a position other than its central position, and a position other than its central position may be used as an evaluation point.

[0118] Furthermore, in the above embodiment, plate-shaped anti-aircraft signs 6 are installed on the road surface or the like, but instead of using plate-shaped anti-aircraft signs 6, a pattern similar to the anti-aircraft signs 6 may be formed on the road surface or the like using any material such as paint. For example, a pattern similar to the anti-aircraft signs 6 may be formed on the asphalt surface of the road by spraying paint of a different color than the asphalt surface to form a pattern having the same shape as the white portion of the anti-aircraft signs 6 in FIG. 3. Even when anti-aircraft signs are formed on the road surface using any material such as paint, the type, shape, size, pattern, etc. of the anti-aircraft signs are also arbitrary. The above content also applies when anti-aircraft signs are fixed to obstacles such as roadside trees.

[0119] In the above embodiment, an anti-aircraft sign 6 formed in the form of a sticker with a backing paper attached to cover the adhesive layer on the back side is used, and the anti-aircraft sign 6 is fixed to the installation location by removing the backing paper and attaching it to the installation location. However, any method for fixing the anti-aircraft sign 6 to the installation location is possible. For example, an anti-aircraft sign with a hole formed therein may be fixed to the installation location using a fixing device (e.g., an anchor pin, etc.). In this case, a mounting hole may be formed in the installation location, such as the road surface, and the anti-aircraft sign may be fixed to the mounting hole using a fixing device. Also, for example, a rod-shaped sign stake with an anti-aircraft sign at its tip may be embedded in the installation location to fix the anti-aircraft sign to the installation location. In this case, by embedding the sign stake in the ground surface, the anti-aircraft sign at the tip of the sign stake is placed on the ground surface. The above content also applies when fixing an anti-aircraft sign to an obstacle, such as a roadside tree.

[0120] In the above embodiment, a method for creating an orthoimage was described, but it is possible to take a photographed image after obtaining the three-dimensional coordinates of the anti-aircraft sign 6, and it is also possible to obtain the three-dimensional coordinates of the anti-aircraft sign 6 after taking the photographed image.

[0121] In the above embodiment, when a part of the road surface is covered by an obstacle when viewed from above, a corrected 3D model and a corrected orthoimage are created in which all of the area covered by the obstacle is corrected to an area not covered by the obstacle, but a corrected 3D model and a corrected orthoimage may be created in which a part of the area covered by the obstacle (for example, at least a part of the road surface and the area other than the road surface) is corrected to an area not covered by the obstacle. Thus, a corrected 3D model and a corrected orthoimage may be created in which the road surface in the area covered by the obstacle is corrected to an area not covered by the obstacle, and the part other than the road surface in the area covered by the obstacle is not corrected to an area not covered by the obstacle.

[0122] In the above embodiment, the first and second image capturing devices are unmanned aerial vehicles (including the image capturing device) that fly at a higher altitude than the obstacle and unmanned aerial vehicles (including the image capturing device) that fly at a lower altitude than the obstacle, respectively. However, this is not limiting. In the present invention, the first and second image capturing devices may be of any type. For example, the first and second image capturing devices may be model aircraft (including the image capturing device) that fly at a higher altitude than the obstacle or a model aircraft (including the image capturing device) that flies at a lower altitude than the obstacle, when capturing a road from a higher altitude than the obstacle or a lower altitude than the obstacle. In the present invention, an unmanned aerial vehicle is an airplane, rotorcraft, airship, or other aircraft that cannot carry a person and can be flown by remote control or automatic piloting, such as a drone (multicopter) or a radio-controlled aircraft. Furthermore, a model aircraft is, for example, a multicopter, radio-controlled aircraft, or other aircraft that weighs less than 200 grams, which is the total weight of the aircraft body and battery. In the above embodiment, when a road is photographed by an unmanned aerial vehicle flying overhead, obstacles that cover a portion of the road surface are not limited to roadside trees around the road. The present invention can be applied to cases where obstacles such as pedestrian bridges and traffic lights located above the road surface cover a portion of the road surface.

[0123] In the above embodiment, an unmanned aerial vehicle (including a camera) that flies at an altitude higher than the obstacle and an unmanned aerial vehicle (including a camera) that flies at an altitude lower than the obstacle are used as the first and second camera devices, but this is not limited thereto. For example, the first and second camera devices may be configured such that the road is photographed by a camera positioned at an altitude higher than the obstacle or a camera positioned at an altitude lower than the obstacle when photographing the road from an altitude higher than the obstacle or a lower than the obstacle.

[0124] For example, an orthoimage creation system according to a modified example of the present invention may include, as shown in FIG. 22, a total station 2 installed at a known point (e.g., a reference point), a UAV3 (Unmanned Aerial Vehicle) that is an unmanned aerial vehicle as an imaging device, a camera 103 as an imaging device, and an orthoimage creation device 10 to which the total station 2, UAV3, and camera 103 are wirelessly connected.

[0125] In this modification, when a road whose surface is partially covered by an obstacle when viewed from above is photographed from an altitude higher than the obstacle, the photograph is taken by UAV 3, and when an area covered by the obstacle is photographed from an altitude lower than the obstacle, the photograph is taken by camera 103. That is, an inspector in an area where part of the road surface is covered by obstacle T operates camera 103 to photograph an area (road surface and obstacle T) that includes multiple anti-aircraft signs 6 installed on the road surface and on parts other than the road surface, such as the side of obstacle T, as shown in FIG. 23. In this case, the inspector moves and takes multiple photographed images of the multiple anti-aircraft signs 6 so that each anti-aircraft sign 6 is included in at least two photographed images.

[0126] In the above embodiment, SfM (Structure from Motion) analysis software is used to create an orthoimage based on the three-dimensional coordinates of the anti-aircraft sign 6 and multiple captured images. The processes performed by the SfM analysis software include: (1) a point cloud generation process that generates a collection of multiple point cloud data corresponding to multiple positions; (2) a TIN process (a meshing process that converts the collection of point cloud data created in the point cloud generation process into a three-dimensional TIN model (irregular triangular network) that is a collection of triangular planes connected at vertices); and (3) an orthoimage creation process that creates an orthoimage based on the three-dimensional TIN model converted in the TIN process. The orthoimages (provisional orthoimages and corrected orthoimages) of the present invention are obtained by performing the orthoimage generation process using SfM analysis software. The 3D models (provisional 3D models and corrected 3D models) of the present invention are obtained by performing the point cloud generation process using SfM analysis software, or by performing the point cloud generation process and then the TIN process using SfM analysis software. In other words, a 3D model (point cloud data) is created by using SfM analysis software to perform the point cloud process, and a 3D model (TINized point cloud data) is created by using SfM analysis software to perform the TIN process after the point cloud process.

[0127] (How to create a corrected orthoimage) In the present invention, SfM analysis is performed on multiple images taken from an altitude higher than the obstacles and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein, and SfM analysis is also performed on multiple images taken from an altitude lower than the obstacles and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein, and a corrected orthoimage is created by integrating these data.

[0128] The following method can be used to create a corrected orthoimage by integrating multiple images taken from an altitude higher than the obstacles, in which SfM analysis has been performed on the three-dimensional coordinates of the anti-aircraft signs 6 contained therein, with multiple images taken from an altitude lower than the obstacles, in which SfM analysis has been performed on the three-dimensional coordinates of the anti-aircraft signs 6 contained therein.In the above embodiment, a case has been described in which the following (integration method 3 for creating a corrected orthoimage) was used, but any integration method can be used to create a corrected orthoimage.

[0129] (Integration method 1 for creating rectified orthoimages) A plurality of photographed images taken from an altitude lower than the obstacles and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein have been subjected to SfM analysis up to the point cloud process, and these images are integrated with a plurality of photographed images taken from an altitude higher than the obstacles and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein have been subjected to SfM analysis up to the point cloud process, and then the integrated data is subjected to the TIN process and the orthoimage creation process to create a corrected orthoimage.

[0130] (Integration method 2 for creating rectified orthoimages) A plurality of photographed images taken from an altitude lower than the obstacles and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein are subjected to a point cloud process and then a TIN process of SfM analysis, and these are then integrated with a plurality of photographed images taken from an altitude higher than the obstacles and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein, which are subjected to a point cloud process and then a TIN process of SfM analysis, and then a corrected orthoimage is created by performing an orthoimage creation process on the integrated data.

[0131] (Integration method 3 for creating rectified orthoimages) A corrected orthoimage is created by integrating SfM analysis, which is carried out on a plurality of photographed images taken from an altitude lower than the obstacles, and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein, through a point cloud process and a TIN process, followed by an orthoimage creation process, with SfM analysis, which is carried out on a plurality of photographed images taken from an altitude higher than the obstacles, and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein, through a point cloud process and a TIN process, followed by an orthoimage creation process.

[0132] (Integration method 4 for creating rectified orthoimages) A corrected orthoimage is created by performing SfM analysis on a combination of multiple images taken from an altitude lower than the obstacle and the 3D coordinates of the anti-aircraft signs 6 contained therein, and multiple images taken from an altitude higher than the obstacle and the 3D coordinates of the anti-aircraft signs 6 contained therein, through a point cloud process, a TIN process, and an orthoimage creation process.

[0133] (How to create a corrected 3D model) In the present invention, SfM analysis is performed on multiple images taken from an altitude higher than the obstacle and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein, and SfM analysis is also performed on multiple images taken from an altitude lower than the obstacle and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein, and a corrected three-dimensional model is created by integrating these data.

[0134] The following methods are available for creating a corrected 3D model by integrating multiple images taken from an altitude higher than the obstacles, in which SfM analysis has been performed on the 3D coordinates of the anti-aircraft signs 6 contained therein, with multiple images taken from an altitude lower than the obstacles, in which SfM analysis has been performed on the 3D coordinates of the anti-aircraft signs 6 contained therein. In the above embodiment, a case has been described in which the following (Integration Method 1 for Creating a Corrected 3D Model) was used, but any integration method for creating a corrected 3D model may be used.

[0135] (Integration method 1 for creating a corrected 3D model) A corrected 3D model is created by integrating multiple images taken from an altitude lower than the obstacle and the 3D coordinates of the anti-aircraft signs 6 contained therein, for which SfM analysis has been performed up to the point cloud process, with multiple images taken from an altitude higher than the obstacle and the 3D coordinates of the anti-aircraft signs 6 contained therein, for which SfM analysis has been performed up to the point cloud process.

[0136] (Integration method 2 for creating a corrected 3D model) A plurality of photographed images taken from an altitude lower than the obstacles and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein have been subjected to SfM analysis up to the point cloud process, and these images are integrated with a plurality of photographed images taken from an altitude higher than the obstacles and the three-dimensional coordinates of the anti-aircraft signs 6 contained therein, which have been subjected to SfM analysis up to the point cloud process, and then a corrected three-dimensional model is created by performing a TIN process on the integrated data.

[0137] (Integration method 3 for creating a corrected 3D model) A corrected 3D model is created by integrating a plurality of photographed images taken from an altitude lower than the obstacles and the 3D coordinates of the anti-aircraft signs 6 contained therein, which have been subjected to a point cloud process followed by a TIN process, with a plurality of photographed images taken from an altitude higher than the obstacles, which have been subjected to a point cloud process followed by an SfM analysis followed by a TIN process, with the plurality of photographed images taken from an altitude higher than the obstacles and the 3D coordinates of the anti-aircraft signs 6 contained therein, which have been subjected to a point cloud process followed by an SfM analysis followed by a TIN process.

[0138] (Integration method 4 for creating a corrected 3D model) A corrected 3D model is created by performing SfM analysis up to the point cloud process on a combination of multiple images taken from an altitude lower than the obstacle and the 3D coordinates of the anti-aircraft signs 6 contained therein, and multiple images taken from an altitude higher than the obstacle and the 3D coordinates of the anti-aircraft signs 6 contained therein.

[0139] (Integration method for creating a corrected 3D model 5) A corrected 3D model is created by performing SfM analysis on a combination of multiple images taken from an altitude lower than the obstacle and the 3D coordinates of the anti-aircraft signs 6 contained therein, and multiple images taken from an altitude higher than the obstacle and the 3D coordinates of the anti-aircraft signs 6 contained therein, through a point cloud process and then a TIN process.

[0140] In the above-mentioned integration method for creating a corrected orthoimage or the integration method for creating a corrected 3D model, multiple images taken from an altitude lower than the obstacle and subjected to SfM analysis on the 3D coordinates of the anti-aircraft signs 6 contained therein are integrated with multiple images taken from an altitude higher than the obstacle and subjected to SfM analysis on the 3D coordinates of the anti-aircraft signs 6 contained therein, but multiple images taken from an altitude higher than the obstacle and subjected to SfM analysis on the 3D coordinates of the anti-aircraft signs 6 contained therein may also be integrated with multiple images taken from an altitude lower than the obstacle and subjected to SfM analysis on the 3D coordinates of the anti-aircraft signs 6 contained therein. [Explanation of symbols]

[0141] 1 Orthoimage creation system 2. Total Station 3 UAV (unmanned aerial vehicle) 4. 3D scanner (3D scanning device) 5 Display section 6 Anti-aircraft markings 10 Orthoimage creation device 11 Coordinate memory section 11a First coordinate storage unit (first coordinate storage means) 11b Second coordinate storage unit (second coordinate storage means) 12. Photographed image storage unit 12a First captured image storage unit (first captured image storage means) 12b Second captured image storage unit (second captured image storage means) 13 Orthoimage Creation Department 13a First orthoimage creation unit (first orthoimage creation means) 13b Second orthoimage creation unit (second orthoimage creation means) 14 Shape detection unit (shape detection means) 15 Display control unit 101 3D model creation system 103 Camera 113 3D Model Creation Department 113a First three-dimensional model creation unit (first three-dimensional model means) 113b Second three-dimensional model creation unit (second three-dimensional model means)

Claims

1. a first photographing step of photographing a road, the road surface of which is partially covered by an obstacle when viewed from above, with a first photographing device from an altitude higher than the obstacle to obtain a plurality of first photographed images; a second photographing step of photographing an area covered by the obstacle with a second photographing device from an altitude lower than the obstacle to obtain a plurality of second photographed images; a first coordinate acquisition step of acquiring three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and that is included in at least two of the plurality of first photographed images; a second coordinate acquisition step of acquiring three-dimensional coordinates of a second feature point that is located in an area covered by the obstacle and that is included in at least two of the plurality of second captured images; an orthoimage creation step of creating a corrected orthoimage in which at least a portion of the area of ​​the road surface covered by the obstacle is corrected to an area not covered by the obstacle, based on a plurality of first photographed images taken in the first photographing step, a plurality of second photographed images taken in the second photographing step, the three-dimensional coordinates of the first feature points acquired in the first coordinate acquisition step, and the three-dimensional coordinates of the second feature points acquired in the second coordinate acquisition step.

2. The orthoimage creation step includes: a first orthoimage creation step of creating a provisional orthoimage in which a part of the road surface is covered by the obstacle based on the plurality of first photographed images photographed in the first photographing step and the three-dimensional coordinates of the first feature points acquired in the first coordinate acquisition step; a shape detection step of detecting a shape of at least a part of the road surface and a part other than the road surface in the area covered by the obstacle, based on the plurality of second photographed images photographed in the second photographing step and the three-dimensional coordinates of the second feature points acquired in the second landmark acquisition step; and a second orthoimage creation step of creating the corrected orthoimage in which at least a portion of the area covered by the obstacle in the provisional orthoimage created by the first orthoimage creation step is corrected to an area not covered by the obstacle. The orthoimage creation method according to claim 1, further comprising:

3. 3. The orthoimage creation method according to claim 1, wherein the first photographing device is an unmanned aerial vehicle or a model aircraft flying at an altitude higher than the obstacle, and the second photographing device is an unmanned aerial vehicle or a model aircraft flying at an altitude lower than the obstacle, or a camera positioned at an altitude lower than the obstacle.

4. In the second photographing step, a plurality of signs are installed on the road surface and the obstacles in the area covered by the obstacles, and the plurality of signs are photographed so as to be included in at least two of the second photographed images as the second feature points. An orthoimage creation method according to any one of claims 1 to 3.

5. a first photographed image storage means for storing a plurality of first photographed images of a road in which a part of the road surface is covered by an obstacle when viewed from above, the first photographed images being photographed by a first photographing device from an altitude higher than the obstacle; a second image storage means for storing a plurality of second images of an area covered by the obstacle, the second images being captured by a second image capturing device from an altitude lower than the obstacle; a first coordinate storage means for storing three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and that is included in at least two of the plurality of first photographed images; a second coordinate storage means for storing three-dimensional coordinates of a second feature point that is located in an area covered by the obstacle and that is included in at least two of the plurality of second photographed images; an orthoimage creation means for creating a corrected orthoimage in which at least a portion of the area of ​​the road surface covered by the obstacle is corrected to an area not covered by the obstacle, based on a plurality of first photographed images stored in the first photographed image storage means, a plurality of second photographed images stored in the second photographed image storage means, the three-dimensional coordinates of the first feature points stored in the first coordinate storage means, and the three-dimensional coordinates of the second feature points stored in the second storage means.

6. The orthoimage creation means a first orthoimage creation means for creating a provisional orthoimage in which a part of a road surface is covered by an obstacle, based on the plurality of first photographed images stored in the first image storage means and the three-dimensional coordinates of the first feature points stored in the first coordinate storage means; a shape detection means for detecting the shape of at least a part of the road surface and a part other than the road surface in the area covered by the obstacle, based on the plurality of second photographed images stored in the second photographing storage means and the three-dimensional coordinates of the second feature points stored in the second coordinate storage means; The orthoimage creation system according to claim 5, further comprising a second orthoimage creation means for creating the corrected orthoimage in which at least a portion of the area covered by the obstacle in the provisional orthoimage created by the first orthoimage creation means is corrected to an area not covered by the obstacle.

7. The orthoimage creation system described in claim 5 or 6, characterized in that the first photographing device is an unmanned aerial vehicle or a model aircraft flying at an altitude higher than the obstacle, and the second photographing device is an unmanned aerial vehicle or a model aircraft flying at an altitude lower than the obstacle or a camera positioned at an altitude lower than the obstacle.

8. The orthoimage creation system described in any one of claims 5 to 7, characterized in that the plurality of second photographed images stored in the second photographed image storage means are photographed so that a plurality of signs installed on the road surface and the obstacles in the area covered by the obstacles are included as the second feature points in at least two of the second photographed images.

9. A marker used in the orthoimage creation method according to claim 4, A sign characterized by being in the form of a sticker with an adhesive layer formed on the back surface.

10. A sign used in the orthoimage creation system according to claim 8, A sign characterized by being in the form of a sticker with an adhesive layer formed on the back surface.

11. a first photographing step of photographing a road, the road surface of which is partially covered by an obstacle when viewed from above, with a first photographing device from an altitude higher than the obstacle to obtain a plurality of first photographed images; a second photographing step of photographing an area covered by the obstacle with a second photographing device from an altitude lower than the obstacle to obtain a plurality of second photographed images; a first coordinate acquisition step of acquiring three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and that is included in at least two of the plurality of first photographed images; a second coordinate acquisition step of acquiring three-dimensional coordinates of a second feature point that is located in an area covered by the obstacle and that is included in at least two of the plurality of second captured images; a three-dimensional model creation step of creating a corrected three-dimensional model in which at least a portion of an area of ​​the road surface that is covered by the obstacle is corrected to an area that is not covered by the obstacle, based on a plurality of first photographed images taken in the first photographing step, a plurality of second photographed images taken in the second photographing step, the three-dimensional coordinates of the first feature points acquired in the first coordinate acquisition step, and the three-dimensional coordinates of the second feature points acquired in the second coordinate acquisition step.

12. The three-dimensional model creation step includes: a first creation step of creating a temporary three-dimensional model in which a part of a road surface is covered by the obstacle, based on the plurality of first photographed images taken in the first photographing step and the three-dimensional coordinates of the first feature points acquired in the first coordinate acquiring step; a shape detection step of detecting a shape of at least a part of the road surface and a part other than the road surface in the area covered by the obstacle, based on the plurality of second photographed images photographed in the second photographing step and the three-dimensional coordinates of the second feature points acquired in the second landmark acquisition step; The three-dimensional model creation method according to claim 11, further comprising a second three-dimensional model creation step of creating a corrected three-dimensional model in which at least a portion of the area of ​​the temporary three-dimensional model created by the first creation step is corrected to an area not covered by the obstacle.

13. 13. The three-dimensional model creation method according to claim 11 or 12, wherein the first image capturing device is an unmanned aerial vehicle or a model aircraft flying at an altitude higher than the obstacle, and the second image capturing device is an unmanned aerial vehicle or a model aircraft flying at an altitude lower than the obstacle, or a camera positioned at an altitude lower than the obstacle.

14. 14. The three-dimensional model creation method according to claim 11, wherein in the second photographing step, a plurality of signs are set on the road surface and on the obstacles in the area covered by the obstacles, and the second photographing step is performed so that the plurality of signs are included as the second feature points in at least two of the second photographed images.

15. a first photographed image storage means for storing a plurality of first photographed images of a road in which a part of the road surface is covered by an obstacle when viewed from above, the first photographed images being photographed by a first photographing device from an altitude higher than the obstacle; a second image storage means for storing a plurality of second images of an area covered by the obstacle, the second images being captured by a second image capturing device from an altitude lower than the obstacle; a first coordinate storage means for storing three-dimensional coordinates of a first feature point that is located outside the area covered by the obstacle and that is included in at least two of the plurality of first photographed images; a second coordinate storage means for storing three-dimensional coordinates of a second feature point that is located in an area covered by the obstacle and that is included in at least two of the plurality of second photographed images; a three-dimensional model creation means for creating a corrected three-dimensional model in which at least a portion of an area of ​​the road surface that is covered by the obstacle is corrected to an area that is not covered by the obstacle, based on a plurality of first photographed images stored in the first photographed image storage means, a plurality of second photographed images stored in the second photographed image storage means, the three-dimensional coordinates of the first feature points stored in the first coordinate storage means, and the three-dimensional coordinates of the second feature points stored in the second coordinate storage means.

16. The three-dimensional model creation means a first three-dimensional model creation means for creating a provisional three-dimensional model in which a part of a road surface is covered by the obstacle, based on the plurality of first photographed images stored in the first photographed image storage means and the three-dimensional coordinates of the first feature points stored in the first coordinate storage means; a shape detection means for detecting the shape of at least a part of the road surface and a part other than the road surface in the area covered by the obstacle, based on the plurality of second photographed images stored in the second photographed image storage means and the three-dimensional coordinates of the second feature points stored in the second coordinate storage means; and a second three-dimensional model creation means for creating the corrected three-dimensional model by correcting at least a portion of the area of ​​the temporary three-dimensional model created by the first three-dimensional model creation means that is covered by the obstacle to an area that is not covered by the obstacle.

17. The three-dimensional model creation system according to claim 15 or 16, characterized in that the first image capturing device is an unmanned aerial vehicle or a model aircraft flying at an altitude higher than the obstacle, and the second image capturing device is an unmanned aerial vehicle or a model aircraft flying at an altitude lower than the obstacle, or a camera positioned at an altitude lower than the obstacle.

18. 18. The three-dimensional model creation system according to any one of claims 15 to 17, wherein the plurality of second photographed images stored in the second photographed image storage means are photographed so that a plurality of signs installed on the road surface and on the obstacles in the area covered by the obstacles are included as the second feature points in at least two of the second photographed images.

19. A marker used in the three-dimensional model creation method according to claim 14, A sign characterized by being in the form of a sticker with an adhesive layer formed on the back surface.

20. A marker used in the three-dimensional model creation system according to claim 18, A sign characterized by being in the form of a sticker with an adhesive layer formed on the back surface.

Images