JP7783093B2 - Prism attachment - Google Patents

Description

The present invention relates to a prism mounting device.

In recent years, three-dimensional point cloud data measured with 3D (three-dimensional) laser scanners has come to be used for purposes such as progress confirmation and as-built measurement at construction sites. For example, by overlaying a 3D model such as BIM (Building Information Modeling) created according to the site's blueprints with point cloud data measured with a laser scanner, progress confirmation and as-built measurement can be easily performed.

In addition, in order to obtain point cloud data for a wider area, multiple point cloud data obtained by scanning from multiple positions with a 3D laser scanner can be synthesized. Also, by placing a target within the measurement range and measuring the point cloud data, the accuracy of synthesizing multiple point cloud data can be improved by using the target's point cloud as a reference.

In addition, the position of the target is accurately measured using surveying equipment, and the obtained target position is used to align the position of the measured point cloud data with absolute coordinates. Accurate alignment improves the accuracy of overlay with the design model.

Spherical targets are also known (for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2020-139891

Spherical targets include spheres, and can be measured with the same shape no matter where you look at them. For this reason, spherical targets can be installed in various locations on-site, such as on ceilings and walls, without having to worry about orientation. However, when accurately measuring the target's position using surveying equipment, it is necessary to install a prism directly facing the surveying equipment at a position that indicates the target's installation position. However, for example, when a spherical target is installed on a wall or ceiling, it can be difficult to install a prism directly facing the surveying equipment at a position that indicates the installation position. As a result, the high degree of freedom in installation position that spherical targets offer can sometimes be hindered by the limitations imposed by surveying using surveying equipment.

In one aspect, the present invention aims to facilitate surveying the installation position of a spherical target.

One embodiment of the present invention provides a prism mounting device that includes a mounting section that is mounted to a spherical target, a rail section attached to the mounting section that includes an arc-shaped rail, and a prism section that includes a prism and moves on the rail. When mounted on the spherical target, the mounting section is arranged so that the sphere of the spherical target and the arc-shaped rail are concentric, and the mounting section includes a rotating section that rotates the rail around an axis that passes through the center of the sphere of the spherical target.

This makes it easier to survey the installation location of spherical targets.

FIG. 1 illustrates a spherical target. FIG. 10 is a diagram illustrating an example of surveying the installation position of a target. 1A and 1B are diagrams illustrating a prism mounting tool according to an embodiment. 10A to 10C are diagrams illustrating an example of movement of the attachment unit according to the embodiment. 6A to 6C are diagrams illustrating the movement of a prism portion according to an embodiment. 10A to 10C are diagrams illustrating the movement of a prism mounting fixture according to an embodiment. 10 is a diagram illustrating an example of the positional relationship between a prism and the center of a sphere of a spherical target. FIG. FIG. 10 is a diagram illustrating an example in which a spherical target is installed on an oblique wall or the like. 10A to 10C are diagrams illustrating the movement of a prism in a prism portion of a prism mounting device according to an embodiment. 10A and 10B are diagrams illustrating an example of an operation flow of measurement using a prism mounting tool according to an embodiment.

Several embodiments of the present invention will be described in detail below with reference to the drawings. Note that corresponding elements in multiple drawings will be designated by the same reference numerals.

As mentioned above, common areas of point cloud data measured from multiple locations are overlaid to synthesize point cloud data over a wider area. In this case, synthesis can be difficult using only the point cloud information of the measured object. For example, when measuring the internal shape of a long tunnel, where similar structures continue continuously over a wide area, there are few distinctive points to use for synthesis, and synthesis may not work well using only the point cloud information of the measured object.

For this reason, targets are placed at the site, point cloud data is measured using a 3D laser scanner so that the target is included, and multiple point cloud data are synthesized using the target's point cloud as a clue. One example of a target used to synthesize multiple point cloud data is a spherical target 100.

Figure 1 is a diagram illustrating a spherical target 100. Figure 1(a) shows a side view of the spherical target 100. The spherical target 100 includes a target portion 101 and an attachment portion 102.

The target portion 101 is, for example, a sphere. The mounting portion 102 has, for example, a function or structure for mounting the spherical target 100 to an object. For example, in FIG. 1, the mounting portion 102 includes a magnet 110, which can be used to mount the spherical target 100 to metal such as rebar used in a building on-site. Note that the mounting portion 102 is not limited to being mounted by a magnet, and an adhesive such as a socket or sticker may also be used.

Figure 1(b) also illustrates a spherical target 100 installed on a wall 150. Even when the spherical target 100 is measured using a 3D laser scanner from different angles, the same spherical point cloud can be obtained for the target portion 101. For example, as shown in Figure 1(b), even if the spherical target 100 is installed at an angle, the spherical shape of the target portion 101 remains the same as when viewed from the side in Figure 1(a). Therefore, when combining multiple point cloud data measured from multiple points, the point cloud of the target portion 101 can be used as a reference. In this way, the spherical target 100 can be installed on the ceiling, wall, etc. of the construction site without worrying about orientation. At construction sites, materials are often placed on the floor, and materials must be transported, making it difficult to install the target on the floor or it may interfere with work. Therefore, spherical targets that can be installed on the ceiling, wall, etc. are highly convenient.

In addition, in order to perform coordinate transformation with greater precision, the target installation position is also accurately measured using surveying equipment such as transits and total stations.

Figure 2 is a diagram illustrating the surveying of a target installation position. For example, as shown in Figure 2(a), a spherical target 100 is to be installed at a certain position. In this case, a surveying instrument 202 is installed at a position whose position coordinates have been specified in advance on a design drawing, and the installation position of the spherical target 100 from that position is determined by surveying.

For example, to measure the installation position of the spherical target 100 using the surveying instrument 202, the prism surface of the prism 203 is placed at a position indicating the installation position of the spherical target 100 so that it faces the surveying instrument 202 approximately directly, as shown in FIG. 2(b). Note that, as an example, facing directly may mean placing the prism surface of the prism 203 approximately parallel to a plane perpendicular to the optical axis of the surveying instrument 202. Furthermore, the position indicating the installation position of the spherical target 100 is, for example, the center position of the target portion 101.

Next, the position of the prism 203 (e.g., X, Y, Z position coordinates) is measured using the surveying instrument 202 to identify the installation position of the spherical target 100.

For example, by using a surveying instrument 202 to survey the position of a reference point 201, the position coordinates of which have been specified in advance on a blueprint, the position of the surveying instrument 202 from the reference point 201 can be determined.

After the survey, the target portion 101 is placed at the position of the prism 203, and the area including the spherical target 100 is measured using a 3D laser scanner.

In the same way, by measuring an area including the spherical target 100 from multiple positions using a 3D laser scanner, it is possible to measure multiple point cloud data including the spherical target 100, whose position has been identified in a design drawing, etc. Then, by overlaying the multiple point cloud data based on the position of the spherical target 100, it is possible to synthesize the multiple point cloud data with high precision. Furthermore, coordinate transformation can be performed with high precision based on the position coordinates of the spherical target 100.

However, in this case, if the installation position of the spherical target 100 and the surveying position of the prism 203 are not aligned with high precision, the accuracy of the coordinate transformation of the point cloud data will decrease. Therefore, to achieve high-precision alignment, the spherical target 100 is precisely installed on a flat surface such as a floor using a spirit level. Furthermore, depending on the installation location of the spherical target 100, such as when the spherical target 100 is installed in the air, it may be difficult to install the prism 203 directly facing the surveying instrument 202 in a position corresponding to the spherical target's installation position. Therefore, although the spherical target 100 offers a high degree of freedom in its installation position as a target for a 3D laser scanner, when performing high-precision coordinate transformation to determine the target's installation position through surveying, the installation position may be limited by the surveying. As a result, the advantage of the spherical target's ability to be installed anywhere may not be fully utilized.

Therefore, it is desirable to provide a prism that makes it easy to measure the installation position of the spherical target 100 regardless of the installation position of the spherical target 100. In the embodiment described below, a prism mounting device 300 for a spherical target is provided.

Figure 3 is a diagram illustrating a prism mounting device 300 according to an embodiment. In Figure 3(a), the prism mounting device 300 includes, for example, a rail portion 301, a prism portion 302, and a mounting portion 303. The rail portion 301 is attached to the mounting portion 303, for example, and includes an arc-shaped rail. The mounting portion 303 has a function or structure for mounting the prism mounting device 300 to the spherical target 100, for example. The mounting portion 303 also has a function or structure for attaching and detaching the rail portion 301, and the rail portion 301 may be detachable. The prism portion 302 includes a prism 310. The prism portion 302 can, for example, fit onto (ride on) the rail portion 301 and move along the rail portion 301. The prism portion 302 may also be detachable from the rail portion 301.

Figure 3(b) shows the rail portion 301, prism portion 302, and mounting portion 303 in a separated state.

Figure 4 illustrates the movement of the mounting portion 303. Figure 4(a) shows the rotation of the rail by the mounting portion 303. As shown in Figure 4(a), the mounting portion 303 includes a first portion 401 and a second portion 402. Figure 4(b) also illustrates a cross-section of the second portion 402 of the mounting portion 303, illustrating the rotating structure of the mounting portion 303. As shown in Figure 4(b), the first portion 401 and the second portion 402 of the mounting portion 102 include an opening 403. The size and shape of the opening 403 may be designed to match the shape and size of the mounting portion 102 of the spherical target 100. As shown in Figure 4(a), the mounting portion 102 can be inserted through the opening 403. Then, by tightening the fixing screw 404, the first portion 401 of the mounting portion 303 can be fixed to the mounting portion 102.

Furthermore, as shown in FIG. 4(b), the second portion 402 of the mounting portion 102 includes an opening 405. The end of the rail portion 301 can be inserted into the opening 405, and the inserted rail portion 301 can be fixed by tightening the fixing screw 406, or the rail portion 301 can be removed by loosening the fixing screw 406. Note that the fixation using the opening and screw shown in FIG. 4 is merely an example, and fixation may be achieved using other configurations.

As shown in FIG. 4(b), the second part 402 may be, for example, a bearing, and includes an inner member 411 and an outer member 412 to which multiple balls 420 are attached. The outer member 412 is sometimes referred to as a rotating part. The inner member 411 is, for example, connected to the first part 401 and fixed to the mounting part 102 together with the first part 401. The multiple balls 420 smoothly rotate on the inner member 411, allowing the outer member 412 to rotate around the inner member 411 as indicated by arrow 430. As a result, when the mounting part 303 is attached to the spherical target 100, the rail part 301 can rotate around the spherical target 100 as indicated by arrow 450, with the longitudinal axial direction of the mounting part 102 as the rotation axis. When the prism mounting device 300 is attached to the spherical target 100, the arc-shaped rail of the rail part 301 is arranged around the sphere of the spherical target 100. Furthermore, when the prism mounting device 300 is attached to the spherical target 100, the center of the target portion 101 of the spherical target 100 and the center of the arc-shaped rail of the rail portion 301 may coincide. When the prism mounting device 300 is attached to the spherical target 100, the arc-shaped rail of the rail portion 301 is arranged concentrically with the sphere of the target portion 101. Therefore, when the mounting device 303 is attached to the spherical target 100, the sphere of the spherical target and the arc-shaped rail are arranged concentrically, and the rail can be rotated around an axis passing through the center of the sphere of the spherical target 100.

Figure 5 illustrates the movement of the prism portion 302. Figure 5(a) shows the prism portion 302 attached to the rail portion 301. Figure 5(b) is a diagram illustrating a cross section of the attachment portion of the prism portion 302 to the rail portion 301. In the example of Figure 5, the rail portion 301 includes a groove 501 with a hollow structure. The groove 501 may be, for example, a groove that opens on the side opposite the target portion 101. As shown in Figure 5(b), the prism portion 302 includes, for example, a prism 310, a support 502 to which the prism 310 is attached, and a disk member 503 attached to the tip of the support 502. Multiple balls 504 are attached to the disk member 503, and the smooth rotation of the balls 504 allows the prism portion 302 to move along the rail groove 501 of the rail portion 301 as indicated by the arrow 520 in Figure 5(a). As the prism portion 302 moves on the rail, for example, the prism 310 moves on a circle concentric with the arc shape of the rail.

Prism section 302 also includes a second rotating section that rotates the prism surface of prism 310 around the axial direction from the center of the arc shape of the rail toward prism 310. For example, ball 504 may function as the second rotating section, and smooth rotation of ball 504 allows prism 310 within rail section 301 to rotate as indicated by arrow 530, with support 502 as the rotation axis. Note that while the example in Figure 5 describes an example in which the entire prism section 302 rotates as indicated by arrow 530, embodiments are not limited to this. For example, in another example, prism 310 may be able to rotate around support 502 as indicated by arrow 530.

As described above, the prism mounting device 300 according to the embodiment can change the position of the prism portion 302 by rotating the mounting portion 303 around its axis (arrow 601) as shown in FIG. 6(a) and by moving the rail portion 301 of the prism portion 302 along the rail (arrow 602). As a result, for example, as shown in FIG. 6(b), even if the spherical target 100 is attached in various orientations to a wall, ceiling, etc., when the prism portion 302 is suspended, these two movements can suspend the prism 310 of the prism portion 302 at a position vertically below the center of the sphere of the spherical target 100.

Furthermore, for example, the prism portion 302 rotates the prism surface of the prism 310 around the axial direction extending from the center of the arc shape of the rail toward the prism 310. For example, the prism portion 302 can be rotated as shown by arrow 603 while suspended vertically below the center of the sphere of the spherical target 100. Therefore, the prism portion 302 can be rotated to match the installation position of the surveying instrument 202, so that the prism 310 faces the surveying instrument 202 directly.

Furthermore, since the prism 310 of the prism section 302 hangs vertically below the center of the spherical target 100, the positional relationship between the prism 310 and the center of the spherical target 100 is maintained constant.

Figure 7 is a diagram illustrating the positional relationship between the prism 310 and the center of the spherical target 100. In Figure 7(a), the spherical target 100 is mounted horizontally, while in Figure 7(b), the spherical target 100 is mounted at an angle. However, because the prism portion 302 hangs vertically below the center of the spherical target 100, even if the spherical target 100 is mounted in various orientations, the center of the spherical target 100 and the horizontal position (position in the X and Y directions) of the prism 310 will coincide as shown in Figure 7. Furthermore, the vertical distance between the center of the spherical target 100 and the prism 310 is a predetermined value A. In other words, when the prism mounting device 300 is attached to the spherical target 100, the prism 310 moves on a circle concentric with the sphere of the target portion 101, so the vertical distance between the center of the sphere of the spherical target 100 and the prism 310 is a predetermined value A. Therefore, when the position coordinates of the prism 310 are determined using the surveying instrument 202, the coordinates of the center of the sphere of the spherical target 100 can be determined by shifting the coordinates by adding A to the Z component of those coordinates, for example.

As shown in Figure 8, even if the spherical target 100 is installed on an inclined wall 150, its position can be identified by placing the prism 310 directly opposite the surveying instrument 202. The center position of the spherical target 100 can then be identified by shifting the Z component of the identified prism 310 by A.

As described above, according to the embodiment, even when a spherical target 100 is used, it is possible to easily identify its installation position. Furthermore, according to the embodiment, it is possible to easily identify the installation position even when the spherical target 100 is installed in various orientations.

The prism portion 302 of the prism mounting device 300 may be provided with a movable portion that allows the prism 310 to move along the axial direction from the center of the arc of the rail portion 301 toward the prism 310. For example, as shown in Figure 8, even if the spherical target 100 is installed on a wall or ceiling higher than the floor, the presence of an obstacle may cause the prism 310 to be in a blind spot when viewed from the position of the surveying instrument 202. Even in such a case, if the position of the prism 310 is movable, it can be moved to a position where the prism 310 is visible.

Figure 9 is a diagram illustrating the movement of the prism 310 in the prism unit 302 according to the embodiment. As shown in Figure 9, the prism 310 in the prism unit 302 can slide and move in a direction along the central axis of the support 502. In one example, the prism 310 may be fixed to the support 502 using fasteners such as a bolt and nut. In this case, for example, the support 502 may have a groove through which the threads of the bolt pass, and the prism 310 may be fixed to the support 502 by turning the bolt attached to the prism 310 to tighten the support 502 between the bolt head and the nut. In this case, the prism 310 may be movable along the support 502 by loosening the bolt. This allows the prism 310 to move along the axial direction from the center of the arc of the rail unit 301 toward the prism 310.

Furthermore, to make it possible to identify the position of the prism 310 when it is moved, the prism portion 302 may have a scale 901 that indicates the position of the prism 310. In the example of Figure 9, the support 502 includes a scale along the axial direction of the support 502, making it possible to identify the position of the prism 310 along the axial direction from the center of the arc of the rail portion 301 toward the prism 310 when the position of the prism 310 is moved.

In the example of Figure 9, the prism portion 302 also includes a weight 902. As mentioned above, the prism portion 302 may be suspended vertically by its own weight, and by including the weight 902 in this manner, the vertical suspension can be made more stable. Furthermore, no manpower is required to secure the prism.

Figure 10 is a diagram illustrating the operational flow of measurements using the prism mounting device 300 according to the embodiment.

In S1001, a reference point 201 whose position on the design drawing is known is surveyed using a surveying instrument 202 such as a transit or total station, and the position of the surveying instrument 202 is determined.

In S1002, the spherical target 100 is installed. The spherical target 100 may be installed in various locations, such as a wall or ceiling.

The prism mounting device 300 is attached to the spherical target 100 installed in S1003. When the prism mounting device 300 is attached to the spherical target 100, for example, the prism portion 302 hangs vertically under its own weight. In addition, the prism surface of the prism in the prism portion 302 can be rotated, allowing the prism surface to be oriented so as to face the surveying instrument 202 directly.

In S1004, the surveying instrument 202 measures the prism 310 of the prism mounting device 300 and determines the position coordinates of the prism 310.

Then, in S1005, the position coordinates (X, Y, Z coordinates) of the spherical target 100 are determined by adding a predetermined value A to the position coordinates of the prism 310.

In S1006, the prism mounting fixture 300 is removed from the spherical target 100.

In S1007, the spherical target 100 is measured from multiple positions using a 3D laser scanner, and multiple point cloud data are obtained.

In S1008, multiple point cloud data are synthesized using the position coordinates of the spherical target 100.

As described above, the position of the spherical target 100 can be identified using the prism mounting device 300, allowing for accurate coordinate alignment and improving the efficiency of post-processing related to point cloud synthesis and coordinate transformation.

Furthermore, the prism mounting device 300 according to the embodiment makes it possible to easily measure spherical targets 100 installed in various locations, such as on walls and ceilings.

As a result, there is no need to install the spherical target 100 in a location that is easy to survey, such as the floor, for surveying purposes, and the spherical target 100's ability to be installed anywhere can be utilized.

For example, when determining the position of the spherical target 100 through surveying, the spherical target 100 can be installed on a wall or ceiling rather than the floor, where it will not interfere with traffic or construction. This makes it possible to leave the spherical target 100 installed for an extended period of time. This eliminates the need to install the spherical target 100 every time a measurement is taken. For example, when using a 3D laser scanner to perform fixed-point observations of the completed work at a construction site, measurements can be taken while the spherical target 100 is installed, which is highly convenient.

A number of embodiments have been described above. However, the embodiments are not limited to the above-described embodiments, and should be understood to include various modifications and alternative forms of the above-described embodiments. For example, it will be understood that the various embodiments can be realized by modifying the components without departing from the spirit and scope of the embodiments. It will also be understood that various embodiments can be implemented by appropriately combining multiple components disclosed in the above-described embodiments. Furthermore, it will be understood by those skilled in the art that various embodiments can be implemented by deleting some components from all of the components shown in the embodiments, or by adding some components to the components shown in the embodiments.

100: spherical target 101: target portion 102: mounting portion 110: magnet 150: wall 201: reference point 202: surveying instrument 203: prism 300: prism mounting fixture 301: rail portion 302: prism portion 303: mounting portion 310: prism 401: first portion 402: second portion 403: opening 404: fixing screw 405: opening 406: fixing screw 411: inner member 412: outer member 420: ball 501: groove 502: support 503: disc member 504: ball 901: scale 902: weight

Claims (6)

a mounting portion that is mounted on the spherical target;
a rail portion attached to the mounting portion, the rail portion including an arc-shaped rail;
a prism unit having a prism and moving on the rail;
A prism mounting device comprising:
the mounting unit includes a rotation unit that rotates the rail around an axis passing through the center of the sphere of the spherical target in an arrangement in which the sphere of the spherical target and the arc shape of the rail are concentric when the mounting unit is mounted on the spherical target;
Prism mounting device. When the prism portion moves on the rail, the prism moves on a circle concentric with the arc shape of the rail.
2. The prism mounting device according to claim 1, wherein the prism mounting device is a prism mounting device. the rotating portion is rotatable by the weight of the prism portion,
the rail portion holds the prism portion so that the prism portion can slide on the rail due to its own weight;
3. The prism mounting device according to claim 1, wherein when the mounting portion is mounted on the spherical target, the prism portion hangs from the rail by its own weight so that the prism is positioned vertically below the center of the sphere of the spherical target. The prism mounting device described in any one of claims 1 to 3, characterized in that the prism portion includes a second rotating portion that rotates the prism surface of the prism around an axis extending from the center of the arc shape of the rail toward the prism. the prism portion includes a movable portion that enables movement of the prism in an axial direction from the center of the arc shape of the rail toward the prism;
and a scale for identifying the position of the prism from the center of the arc shape.
The prism mounting device according to any one of claims 1 to 4. The prism mounting device according to claim 1 , wherein the rail portion is detachable from the mounting portion.