Surveying data processing apparatus, method for surveying data, and surveying data processing program

Abstract

To constrain the issue that a light reflector other than a target is erroneously detected as a target in surveying.SOLUTION: A bright spot having a reflected light intensity exceeding a threshold is detected as a high-brightness point from laser scan data obtained for a range including reflecting prisms 21 and 22. It is then determined whether the high-brightness point corresponds to a directly reflected light point from the reflecting prisms 21 and 22. In this determination, position information of reflectors corresponding to high-brightness points determined not to be direct reflections from the reflecting prisms 21 and 22 (such as position information of a sign 31, a curved mirror 32, and a glass surface 33 exhibiting high reflectance) is stored. By using this reflector position information, erroneous detection of surveying targets in other surveying operations can be suppressed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the art of surveying. [Background technology]

[0002] Surveying using laser scanners and total stations that use laser ranging light is well known. In surveying using laser light, a light reflector (a reflective mirror or reflective prism) that reflects the surveying light with high efficiency is used as the target.

[0003] At surveying sites, in addition to reflectors used as targets, signs, light reflectors for safety checks (light reflectors placed on guardrails, etc., or light reflectors on vehicles), glass surfaces or walls with high light reflectivity, convex mirrors, water surfaces, etc. may also function as reflectors for surveying laser light.

[0004] In measurements using laser light, there is a risk that measurements may be performed on light reflectors other than the above targets. This problem is described in, for example, Patent Documents 1 to 3. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-152543 [Patent Document 2] Japanese Patent Application Publication No. 2023-119546 [Patent Document 3] Japanese Patent Application Publication No. 2024-11167 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to provide a technique for suppressing the problem of mistaking a light reflector other than a target for a target in surveying. [Means for solving the problem]

[0007] The present invention is a surveying data processing device that includes a high-brightness spot detection unit that detects bright spots with reflected light intensities exceeding a threshold as high-brightness spots from laser scan data for an area including a surveying target, a judgment unit that determines whether the high-brightness spots are bright spots of light directly reflected from the surveying target, and a memory unit that stores position information of reflectors of the high-brightness spots that are determined not to be light directly reflected from the surveying target in the judgment.

[0008] In the present invention, the highly luminous points are grouped together to form multiple clusters, and the judgment is made based on a comparison of the shape and dimensions of the surveying target, which have been acquired in advance, with the shape and dimensions of the reflectors of the highly luminous points, which are determined from the point cloud that makes up the clusters.

[0009] In the present invention, the highly luminous points that are determined not to be light reflected directly from the survey target are mirror images of the survey target reflected on the reflector, and the position of the reflector on which the mirror image is reflected is determined based on the distance measurement value L1 of the highly luminous points that are determined not to be light reflected directly from the survey target, the distance measurement value L2 of the highly luminous points that are determined to be light reflected directly from the survey target, the angle between the vector related to L1 and the vector related to L2, and the direction of the highly luminous points that are determined not to be light reflected directly from the survey target, and an example of an embodiment in which the mirror image is obtained by searching for a set of bright points that is the same as or can be considered to be the same as the distribution of bright points of the laser scanning light reflected from the survey target.

[0010] The present invention is a surveying data processing method that detects bright spots with reflected light intensities exceeding a threshold as high-brightness spots from laser scan data for an area including a surveying target, determines whether the high-brightness spots are bright spots of light directly reflected from the surveying target, stores position information for reflectors of high-brightness spots that are determined not to be light directly reflected from the surveying target in the determination, performs an optical scan of the surveying target or another surveying target in an area overlapping with the area where the laser scan was performed, detects bright spots with reflected light intensities exceeding a threshold as high-brightness spots from the optical scan data, and determines whether the high-brightness spots are light directly reflected from the surveying target or another surveying target by comparing the direction of the high-brightness spots with the direction of the reflectors.

[0011] The present invention is a surveying data processing program that is read and executed by a computer, and causes the computer to function as a high-brightness spot detection unit that detects bright spots with reflected light intensities exceeding a threshold as high-brightness spots from laser scan data for an area including a surveying target, a judgment unit that determines whether the high-brightness spots are bright spots of light directly reflected from the surveying target, and a memory unit that stores position information of reflectors of the high-brightness spots that are determined not to be light directly reflected from the surveying target in the judgment. [Effects of the Invention]

[0012] According to the present invention, the problem of mistaking a light reflector other than a target for a target in surveying can be suppressed. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is an image diagram of an embodiment. [Figure 2] FIG. 1 is an image diagram of an embodiment. [Figure 3] FIG. 2 is a block diagram of a survey data processing device. [Figure 4] FIG. 1 is a block diagram of a total station. [Figure 5] 10 is a flowchart illustrating an example of a processing procedure. [Figure 6] 10 is a flowchart illustrating an example of a processing procedure. [Figure 7] FIG. 1 is a diagram illustrating the principle of determining the position of a mirror surface on which a mirror image is reflected. [Figure 8] FIG. 1 is a diagram illustrating the principle of determining the position of a mirror surface on which a mirror image is reflected. DETAILED DESCRIPTION OF THE INVENTION

[0014] 1. First embodiment (overview) 1 shows a state in which a laser scan of the surroundings is performed using a laser scanning device (laser scanner) 100. Within the laser scan range, reflecting prisms 21 and 22 are placed as reference targets whose positions in an absolute coordinate system are known. The reflecting prisms 21 and 22 are an example of a surveying target, such as a full-circle reflecting prism. The absolute coordinate system is a coordinate system used in maps and GNSS, and describes a position using, for example, latitude, longitude, and altitude.

[0015] From the laser scan data of the reflecting prisms 21 and 22, the positions of two different points in the absolute coordinate system and their directions as seen from the laser scanning device 100 are obtained, and the position and orientation of the laser scanning device 100 in the absolute coordinate system are calculated by the resection method. This makes it possible to describe the point cloud data acquired by the laser scanning device 100 in the absolute coordinate system. Note that, to improve calculation accuracy, reflecting prisms may be placed at three or more known points (reference points).

[0016] The scanning light reflected from the reflecting prisms 21 and 22 is identified based on the intensity of the received light. That is, since the reflecting prisms reflect the scanning light with high efficiency, received light whose intensity exceeds a predetermined threshold is identified as reflected light from the reflecting prism. However, this method has the following problems.

[0017] FIG. 1 shows a case where a light-reflective sign 31, a convex mirror 32, and a light-reflective (mirror-like) glass surface 33 are included in the scan range. In this case, the reflected light of the scanning light from the sign 31 may be mistakenly detected as reflected light from a reflecting prism. Furthermore, the reflected light resulting from the mirror image of the reflecting prism 21 reflected on the convex mirror 32 (the scanning light passing through the laser scanning device 100, the convex mirror 32, and the reflecting prism 21) may be mistakenly detected as a direct reflection from the reflecting prism 21. Furthermore, the reflected light resulting from the mirror image of the reflecting prism 22 reflected on the glass surface 33 (the scanning light passing through the laser scanning device 100, the glass surface 33, and the reflecting prism 22) may be mistakenly detected as a direct reflection from the reflecting prism 22. The mirror image may also be a highly efficient reflector other than a reflecting prism.

[0018] Using the method described below, bright spots caused by signs 31, convex mirrors 32, glass surfaces 33, etc., which are factors in the above-mentioned false detection, are distinguished from bright spots of objects that are not targets. Position information of reflectors related to the bright spots that are factors in the above-mentioned false detection, for example, in the case of Figure 1, position information related to the presence of light-reflective sign 31, convex mirror 32, and glass surfaces 33 that are factors in the mirror image of a reflecting prism, is stored as "position information of reflectors of bright spots determined not to be light directly reflected from a surveying target."

[0019] Here, consider a case where surveying work is performed at the site shown in Fig. 1 after point cloud data is acquired using the laser scanning device 100. Surveying is the work of identifying the position information determined on the drawing at the actual site and marking it (for example, by driving a stake).

[0020] Fig. 2 shows a situation in which staking is performed using a total station 200 at the construction site of Fig. 1. In Fig. 2, a worker 41 holds a reflecting prism 42 as a target, and the total station 200 supplements and tracks the reflecting prism 42 that moves together with the worker 41.

[0021] The total station 200 measures the position of the reflecting prism 42 in an absolute coordinate system and transmits this position information to a terminal (not shown) held by the worker 41. The positional relationship between the staking and installation point and the reflecting prism 42 is displayed on the screen of this terminal, and the worker 41 identifies the staking and installation point and performs work such as marking the measurement contact point by referring to the display on the screen. This technology is described, for example, in Japanese Patent No. 5124319 and Japanese Patent Laid-Open No. 2017-133981.

[0022] Here, a method in which the total station 200 automatically searches for and captures the reflecting prism 42 and measures its position is useful in terms of labor savings. In this case, there is a concern about the problem of false detection of the reflecting prism, as described in relation to Figure 1. That is, there is a concern that the reflected light of the search light from the sign 21 may be falsely detected as reflected light from the reflecting prism 42, or that the mirror image of the reflecting prism 42 caused by the convex mirror 32 or glass surface 33 may be falsely detected as directly reflected light from the reflecting prism 42.

[0023] To prevent this problem from occurring, the aforementioned "position information of high-brightness reflectors determined not to be direct reflections from the survey target" is used to eliminate information on suspicious high-brightness points detected by the toll station 200.

[0024] Specifically, it is determined whether the detected bright spot is in the direction of a reflector that may be mistaken for a target acquired in advance, thereby preventing the total station 200 from mistakenly detecting anything other than the reflecting prism 42.

[0025] (laser scanning device) The following describes the laser scanning device 100. The laser scanning device 100 includes a tripod 11, a base unit 12 fixed to the top of the tripod 11, a horizontal rotation unit 13 capable of horizontal rotation on the base unit 12, and a vertical rotation unit 14 disposed on the horizontal rotation unit 13 and capable of vertical rotation.

[0026] The vertical rotation unit 14 rotates around a horizontal axis (this rotation is referred to as vertical rotation). An optical unit that emits and receives scanning light is arranged in the vertical rotation unit 14, and pulsed scanning light is emitted from there. The scanning light reflected from the target travels in reverse along the same path as the outward path and is received by the optical unit. Laser scanning is performed by emitting and receiving the pulsed light while rotating the horizontal rotation unit 13 horizontally and rotating the vertical rotation unit 14 vertically.

[0027] The horizontal rotation of the horizontal rotation unit 13 is performed electrically, and its angle is precisely measured by an encoder. The vertical rotation of the vertical rotation unit 14 is performed electrically, and its angle is precisely measured by an encoder. The distance to the reflection point of the scanning light is calculated using the principle of optical ranging. These are the same as those of a normal laser scanning device.

[0028] Point cloud data is a collection of positional information about the reflection points of each scanning light. For example, point cloud data is composed of data on the direction and distance from the laser scanning device 100 to each scanning point (a reflection point of the pulsed scanning light). Here, if the position and orientation of the laser scanning device 100 in the absolute coordinate system are known, the point cloud data can be described in the absolute coordinate system. Note that information about the intensity of the reflected light (the brightness of the bright spots of the reflection points) is also associated with the point cloud data.

[0029] (Survey data processing device) The laser scanning device 100 incorporates a survey data processing device 110 shown in Fig. 3. The survey data processing device 110 may also be provided separately from the laser scanning device 100.

[0030] The survey data processing device 110 is a computer, and the functional units described below are realized by executing dedicated software. The survey data processing device 110 includes a laser scan data acquisition unit 101, a high brightness spot detection unit 102, a target determination unit 103, a target position acquisition unit 104, a scanner position and orientation calculation unit 105, a non-target reflector position information acquisition unit 106, and a non-target reflector position information storage unit 107.

[0031] The laser scan data acquisition unit 101 receives and acquires point cloud data measured by the laser scanning device 100. The bright spot detection unit 102 detects points from the acquired point cloud data where the received light intensity of reflected light exceeds a threshold. A predetermined threshold is used.

[0032] The target determination unit 103 determines whether the detected bright spot is a bright spot of light directly reflected from the target reflecting prism by the following method. Here, the above determination is made by the method described below.

[0033] Generally, when considering a specific object, multiple scan beams hit the object, resulting in multiple scan points for that object. Therefore, high-brightness points exist as a dispersed distribution of multiple partial collections of scan points. This partial collection of high-brightness points is called a subpopulation of high-brightness points. For example, a subpopulation of high-brightness points formed by multiple reflection points on the reflecting prism 21, or a subpopulation of high-brightness points formed by multiple reflection points on the sign 31, etc. Note that as the distance increases, the density of scan points decreases, and there may be cases where there is only one scan point. Furthermore, there may be cases where the object is small and there is only one scan point. However, these are rare phenomena in laser scanning of the target of interest here.

[0034] First, the shape and size (dimensions) of the object that reflected the above-mentioned subgroup of highly luminous points are estimated. The interval between scan points at a specific distance can be calculated from the scanning conditions. Therefore, once the measurement distance is known, the shape and size (dimensions) of the object that forms the basis of the subgroup of highly luminous points at that distance can be calculated from the distribution of points in that subgroup. In the case of highly luminous points, errors in the measurement distance occur due to saturation of the light-receiving element, but the approximate size of the reflective object can be estimated.

[0035] Since the shape and dimensions of the effective reflection area of ​​a reflecting prism are known, this information is compared with the estimated shape and dimensions of the reflector of the high-brightness spot described above to distinguish between reflecting prisms and non-reflecting prisms (first distinction).

[0036] In other words, if the shape and dimensions of the reflector obtained from the point cloud of a subgroup of highly bright points match or can be considered to match the shape and dimensions of the reflecting prism at that measured distance, the subgroup of highly bright points is determined to be a bright point of the reflecting prism.

[0037] On the other hand, if the shape and dimensions of the reflector obtained from the point cloud of a subgroup of highly bright points differ from the shape and dimensions of the reflecting prism at that measured distance, the subgroup of highly bright points is determined to be bright points of a non-reflecting prism.

[0038] In addition to the first classification described above, the following second classification is also performed. The second classification prevents erroneous detection of bright spots in the mirror image of the reflecting prism reflected on the mirror surface as bright spots of reflected light directly reflected from the reflecting prism. The second classification utilizes the fact that the optical path length L1 of the scanning light from the reflecting prism via the mirror surface is longer than the optical path length L2 of the scanning light directly reflected from the reflecting prism.

[0039] For example, consider the case in which a mirror image 21 of a reflecting prism 21 is reflected on the convex mirror 32 in FIG. 1 and the laser scanning device 100 measures distance to that mirror image. In this case, the path of the scanning light (distance measurement light) is the laser scanning device 100 ⇔ the convex mirror 32 ⇔ the reflecting prism 21. The distance L1 of this path is longer than the distance L2 of the straight line (the optical path of the directly reflected light) connecting the laser scanning device 100 and the reflecting prism 21. In other words, L1 > L2. Therefore, if the approximate position of the laser scanning device 100 is known, L2 is known, and the bright spot of the distance measurement value L1 is suspected to be a mirror image reflected on the mirror surface. In this case, the bright spot is not detected as the reflecting prism 21. The approximate position of the laser scanning device 100 can be determined by standalone positioning using GNSS. This can be performed using a smartphone with GNSS functionality or a GNSS positioning device equipped in the laser scanning device 100.

[0040] By performing the above two methods of discrimination, it is possible to determine whether a bright spot with a brightness exceeding a threshold is a bright spot resulting from light directly reflected from a reflecting prism or not.

[0041] In addition to the above methods, there are also the following methods. The first method utilizes the relationship between the distance to the bright spot and the intensity of the received light. When the distance becomes long enough, the detected intensity of the reflected light from the reflective prism does not decrease, but the detected intensity of the reflected light from the non-reflective prism becomes relatively low. This phenomenon is used to distinguish between scanning light that is directly reflected from the reflective prism and scanning light that is not.

[0042] The second method utilizes the positional relationship of reflecting prisms installed at reference points. For example, the positions of reflecting prisms 21 and 22 are known, and their relative vectors are also known. Therefore, two bright spots in the relative vector relationship are detected as reflected light from reflecting prisms 21 and 22.

[0043] If there are three or more reflecting prisms, their relative positions are determined, and one method is to determine the bright spots of the three reflecting prisms by searching for combinations of bright spots that are in that relative position.

[0044] Furthermore, using the GNSS positioning function of a smartphone or the like, it is possible to determine the approximate position of the laser scanning device 100 in the absolute coordinate system with an accuracy of a few meters or less. Since the positions of the reflecting prisms 21 and 22 are known, another method is to identify the light directly reflected from the reflecting prisms 21 and 22 by searching for a high-brightness point that satisfies the positional relationship between the laser scanning device 100 and the reflecting prisms 21 and 22.

[0045] The third method is to use captured images. In this case, the laser scanning device 100 is equipped with a camera. This camera captures still or video images. The position and orientation of this camera within the laser scanning device 100 are known, and the point cloud data obtained by the laser scanning device 100 can be superimposed on the captured image by the camera, allowing the correspondence between the screen position in the captured image and the point cloud data to be determined.

[0046] In this case, an image of the reflecting prism is acquired in advance, and by determining whether the image corresponding to the highly bright point matches the image, it is determined whether the highly bright point is a bright point of the reflecting prism.

[0047] The determination can also be made by combining two or more of the above-described methods.

[0048] The target position acquisition unit 104 acquires the position information of the target based on the determination by the target determination unit 103. In the case of Fig. 1, the sign 31 determined to be a non-target, the mirror image reflected in the convex mirror 32, and the mirror image reflected on the glass surface 33 are not detected as bright spots on the reflecting prisms 21 and 22, but the bright spots of the reflected light directly reflected from the reflecting prisms 21 and 22 are extracted as the reflected light from the reflecting prisms 21 and 22, and their positions are acquired.

[0049] The scanner position and orientation calculation unit 105 calculates the position and orientation of the laser scanning device 100 in the absolute coordinate system by the resection method based on the information on the positions of the reflecting prisms 21 and 22 in the absolute coordinate system acquired by the target position acquisition unit 104.

[0050] The non-target reflector position information acquisition unit 106 acquires position information of non-target reflectors that are high-brightness points, i.e., "position information of high-brightness reflectors determined not to be directly reflected light from a surveying target." The "position information of high-brightness reflectors determined not to be directly reflected light from a surveying target" includes two types of positions. The first type of position information is position information of reflectors that are directly reflected light, such as sign 31, but are not directly reflected light from a target (reflecting prisms 21 and 22 in the case of Figure 1). The second type of position information is position information of reflectors that cause mirror images (such as curved mirror 32 and glass surface 33 in the case of Figure 1). Note that the position information is a value in an absolute coordinate system.

[0051] Below, we will explain how to obtain "position information of a high-brightness reflector that is determined not to be a direct reflection from a surveying target" related to a mirror image. Figure 7 is a diagram illustrating the principle of this method. Figure 7 shows an example in which a mirror surface is located at position A, and a mirror image of a reflecting prism located at position C is reflected on the mirror surface, and the laser scanner detects this as being located at position B.

[0052] First, from the high-brightness points obtained by laser scanning, a point cloud of a subgroup of high-brightness points caused by light directly reflected from the reflecting prism is extracted. Next, from this subgroup of high-brightness points, a subgroup of high-brightness points whose distribution is the same as, or can be considered to be the same as, the subgroup of high-brightness points related to position C is searched for. This becomes the subgroup of high-brightness points related to the mirror image of the reflecting prism at position C. The center position of this subgroup of high-brightness points is measured as position B.

[0053] Here, position C is acquired by the function of the target position acquisition unit 104, and position B is detected as the position of a bright spot on the mirror image of the reflecting prism. A is the reflection point of the mirror image. Here, AB=AC...Equation 1, OA+AB=L1...Equation 2, and AC can be calculated from the cosine theorem. 2 =OA 2 +L2 2-2(OA)L2cosθ...Equation 3 holds. L1, L2, and θ are obtained from the laser scan data. From equations 1 and 2, AC = L1-OA, and by substituting this into equation 3, the unknown OA can be found.

[0054] By determining the length of OA, the position of reflection point A can be determined based on vector OA (or the direction from point O to point B). This makes it possible to determine the position of the reflector in which the mirror image is reflected. In the case of Figure 1, the positions of the curved mirror 32 and glass surface 33 can be determined. In this way, "position information of the high-brightness reflector determined not to be a direct reflection from the surveying target" related to the mirror image is obtained.

[0055] 7, a high-brightness point determined not to be a reflection from the survey target (reflector prism) is a mirror image of the survey target (reflector prism) reflected by a mirror surface (reflector surface A). The position of the reflector (reflector surface A) on which the mirror image is reflected is determined based on the distance measurement value L1 of the high-brightness point determined not to be a direct reflection from the survey target, the distance measurement value L2 of the high-brightness point determined to be a direct reflection from the survey target, the angle (θ) between the vector related to L1 (vector OA or vector OB) and the vector related to L2 (vector OC), and the direction of the high-brightness point determined not to be a direct reflection from the survey target (vector OA). Here, the mirror image of the survey target is obtained by searching for a "local group (subgroup) of bright points" that has the same or can be considered to have the same distribution as a subgroup (aggregate) of bright points on the survey target, using the bright points detected by the high-brightness point detection unit 102 as the target. In the case of a mirror surface with a large area, the mirror surface can also be determined by the method shown in FIG.

[0056] It is also possible to identify the mirror surface that causes the mirror image of the reflecting prism based on an image captured by a camera. In this case, image information of the card mirror 32 or the glass surface 33 that functions as a mirror surface is acquired in advance as prior information, and the image of the target with a high brightness point is compared with the above prior information to determine whether the reflective surface of the high brightness point is a mirror surface.

[0057] The non-target reflector position information storage unit 107 stores the "position information of the high-brightness reflectors that are determined not to be direct reflections from the survey target." This stored information is used in other surveys that are carried out later.

[0058] (total station) 4 is a block diagram of the total station 200. The total station 200 includes a distance measurement unit 201, a direction measurement unit 202, a target search unit 203, a high-brightness point detection unit 204, a target determination unit 205, and a target capture unit 206.

[0059] The distance measurement unit 201 measures the distance to the aiming point based on the principle of optical ranging. The direction measurement unit 202 measures the direction of the aiming point. The target search unit 203 searches for an optical target such as a reflecting prism. This technology is described in, for example, Japanese Patent No. 5124319 and Japanese Patent Laid-Open No. 2017-133981.

[0060] The function of the target search unit 203 will be briefly described below. It is assumed that the position and orientation of the total station 200 in the absolute coordinate system are known. First, the optical axis of the total station 200 is directed in the general direction of the target, the reflecting prism 42 (see FIG. 2). The general direction of the reflecting prism 42 is acquired, for example, from GNSS information of the operator 41 holding the reflecting prism 42.

[0061] Next, the direction of the approximate predicted position of the reflecting prism 42 is scanned using a search scanning light, and a highly bright spot where the intensity of the detected light exceeds a threshold is detected. This detection is performed in a highly bright spot detection unit 204. Once a highly bright spot is detected, control (collimation control) is performed to point the optical axis of the tortoise station 200 in the direction of the highly bright spot. Collimation control in the direction of the target and collimation control in the direction of the highly bright spot are performed in the target search unit 203. Laser light is used as the search scanning light, but it is also possible to use light other than laser light.

[0062] The target determination unit 205 determines whether the bright spot detected by the target search unit 203 is derived from the target or from a non-target (non-target includes a mirror image of the target). The same problem as in Figure 1 occurs when searching for a target in the total station 200. Therefore, the following method is used to determine whether the detected bright spot is a directly reflected light from the target.

[0063] Here, the judgment is made using the position information in the absolute coordinate system of the non-target highly luminous reflective surface (e.g., sign 31) obtained by the non-target reflector position information acquisition unit 106 (see Figure 3), and the position information in the absolute coordinate system of the reflective surface that causes the high-brightness mirror image (convex mirror 32 and glass surface 33 in the example of Figure 1).

[0064] Here, if the direction of a highly bright point seen from the total station 200 (a highly bright point detected by the highly bright point detection unit 204) is the direction of a highly bright point related to an already acquired non-target (for example, the direction of sign 31), the highly bright point is determined to be a non-target. Also, if the direction of a highly bright point seen from the total station 200 is the direction of a reflector that causes an already acquired high-brightness mirror image (the direction of the curved mirror 32 or glass surface 33), the highly bright point is determined to be a non-target.

[0065] On the other hand, if the above two determinations are NO, it is determined that the high brightness spot in question is a brightness spot of directly reflected light reflected from the target. These determination processes are performed in the target determination unit 205.

[0066] The target acquisition unit 206 performs control to track an object determined to be a target. This control is performed as follows: First, after the target has been acquired, a target scan is performed in a narrow range including the target.

[0067] When movement of the captured target is detected, the optical axis of the total station 200 is finely adjusted so that the target is captured on the optical axis. By repeating this operation control, the target is tracked. This tracking control is performed by the target capture unit 206.

[0068] For example, when the reflecting prism 42 is captured, even if the reflecting prism 42 moves, the collimation is performed on the reflecting prism 42 so as to follow it, and its position is measured.

[0069] (Example of processing: laser scanning) Fig. 5 is a flowchart showing an example of the procedure of processing performed in the laser scanning device 100. The processing shown in Fig. 5 is executed by a computer installed in the laser scanning device 100. A program for executing the processing in Fig. 5 is stored in a storage device of the computer. This program can also be stored in an appropriate storage medium and downloaded from there.

[0070] Prior to the process, the laser scanning device 100 is installed in the environment where the laser scanning will be performed. The exact position and orientation of the laser scanning device 100 are unknown. The approximate position of the laser scanning device 100 may be measured in advance using the GNSS function of a smartphone. In addition, reflecting prisms 21 and 22 (see FIG. 1) are installed at reference points whose positions in the absolute coordinate system are known. In this state, the following process is executed.

[0071] First, a normal scan, which is the first laser scan, is performed (step S101). The normal scan is performed for the entire circumference under scanning conditions to obtain point cloud data of the survey target. The obtained point cloud data includes data on the direction and distance of each point (reflection points of scanning light: scanning points) with the laser scanner 100 as the origin, and data on the received light intensity of the reflected light at each point.

[0072] Under normal scanning conditions, the light reflected from the reflecting prisms 21 and 22 or other highly efficient light reflectors (e.g., sign 31) overflows the light receiving elements, causing saturation. As a result, the accuracy of distance measurement data for bright spots exceeding the threshold decreases. Specifically, for example, distance measurement accuracy of 5 mm or less under normal operation decreases to a level of several centimeters to several tens of centimeters (the decrease in accuracy depends on the degree of saturation).

[0073] After a normal scan (step S101), points with received light intensity exceeding a threshold are detected as high-brightness points from the point cloud obtained by the normal scan (laser scan point cloud) (step S102). This process is performed by the high-brightness point detection unit 102 in FIG. 3.

[0074] Next, from the highly bright points detected in step S102, the bright points of the reflecting prisms 21 and 22 are identified (step S103). This process is performed by the target determination unit 103.

[0075] Next, the positions of the reflecting prisms 21 and 22 identified in step S103 in the absolute coordinate system are acquired (step S104). The positions of the reflecting prisms 21 and 22 in the absolute coordinate system are known, and this position data is acquired here. This process is performed by the target position acquisition unit 104.

[0076] Next, a dimming scan is performed to measure the accurate positions of the reflecting prisms 21 and 22 (step S105). In the dimming scan, an optical attenuator is inserted into the optical path in the laser scanning device 100, and laser scanning is performed under conditions that do not saturate the light receiving elements. The dimming scan is performed within a narrowed range in the direction of the reflecting prisms 21 and 22. Of course, a dimming scan can also be performed over the entire circumference.

[0077] Next, based on the position data of the reflecting prisms 21 and 22 obtained by the dimming scan, the position and orientation of the laser scanning device 100 in the absolute coordinate system are calculated by the resection method (step S106). This process is performed by the scanner position and orientation calculation unit 105.

[0078] Since the positions of the reflecting prisms 21 and 22 in the absolute coordinate system are known, the position and orientation of the laser scanning device 100 in the absolute coordinate system can be calculated by the backward intersection method by measuring the positions of the reflecting prisms 21 and 22 using the laser scanning device 100. This process is performed in step S106.

[0079] Next, position information relating to the high-brightness points extracted in step S102 and not identified as reflecting prisms in step S103 is acquired as position information of non-target reflectors (step S107). In step S106, the position and orientation of the laser scanning device 100 in the absolute coordinate system are determined. Therefore, the "position information of non-target reflectors" acquired here is in the absolute coordinate system. This process is performed by the non-target reflector position information acquisition unit 106.

[0080] The position information of non-target reflectors includes two types of information: (1) position information in the absolute coordinate system of reflectors that may be mistaken for targets, and (2) position information in the absolute coordinate system of reflectors that constitute the reflective surface of the mirror image of a high-brightness point that may be mistaken for a target. An example of (1) is the position information of sign 31. An example of (2) is the position information of convex mirror 32 and glass surface 33. The position information of non-target reflectors is stored in non-target reflector memory unit 107 and kept in a state that can be used later (step S108).

[0081] Based on the position and orientation in the absolute coordinate system of the laser scanning device 100 obtained in step 106, the point cloud data of the survey object acquired in the normal scan in step S101 is converted to coordinates in the absolute coordinate system, thereby obtaining point cloud data in the absolute coordinate system (step S109). This process may be performed within the laser scanning device 100 immediately after step S106, or may be performed using an external device during post-processing or when using the survey data.

[0082] (Example of processing: Stakeout) An example of a case where staking out is performed at the same survey site after the processing of Figure 5 will be described. Figure 6 is a flowchart showing an example of the procedure of processing performed in the total station 200. The processing shown in Figure 6 is executed by a computer installed in the total station 200. A program for executing the processing of Figure 6 is stored in the storage device of the computer. It is also possible to store this program in an appropriate storage medium and download it from there.

[0083] Prior to the process, a total station 200 is installed in the environment where the surveying will be performed (see FIG. 2). The position and orientation of the installed total station 200 are assumed to be known. Furthermore, it is assumed that a worker 41 carrying a reflecting prism 42 measures his / her own position information using a GNSS positioning device (not shown) that he / she carries and transmits the information to the total station 200.

[0084] First, based on the position information of the worker 41, the general direction of the worker 41 as seen from the total station 200 is acquired, and a scan is performed to search for targets in that direction (step S201). If a bright spot is detected in this scan (step S202), the position information of the non-target reflector acquired in step S107 of Fig. 5 is acquired (step S203).

[0085] Next, it is determined whether the highly bright spot whose position information was acquired in step S202 is in the direction of the non-target reflector acquired in step S203 (step S204).

[0086] In step S204, a check is made to see if the direction of the bright spot detected in step S202 is the direction of the non-target reflector stored in step S108.

[0087] If the direction of the high brightness point acquired in step S203 is the direction of the non-target reflector acquired in step S203, the process proceeds from step S204 to step S201, and the processes from step S201 onwards are performed again. In this case, the next target search process is performed.

[0088] If the direction of the highly bright spot acquired in step S203 is not the direction of the non-target reflector acquired in step S203, the process proceeds from step S204 to step S205. In step S205, the highly bright spot detected in step S202 is acquired as the target, i.e., the bright spot of the reflecting prism 42. This allows the total station 200 to capture the reflecting prism 42.

[0089] Next, the position of the reflecting prism 42 is measured using the positioning function of the total station 200 (step S206), and the position information and the position information of the staking point are transmitted to the terminal of the worker 41 (step S207). Transmission is performed using a wireless LAN or the like. By this transmission, the position of the staking point and the position of the reflecting prism 42 are displayed on the terminal as map information. The worker 41 moves to the staking point using this display as a reference.

[0090] Meanwhile, the total station 200 tracks the reflecting prism 42 that moves in accordance with the movement of the worker 41, and continuously measures its position (step S208). The position data of the reflecting prism measured during tracking is continuously transmitted to the terminal carried by the worker 41.

[0091] When the staking out work is completed, the worker 41 operates the portable terminal to transmit that information to the total station 200. Upon receiving this transmission, a determination is made in step S209, and if there is a next staking out work, the process returns to step S201;

[0092] 6 prevents the total station 200 from erroneously detecting a target. For example, it prevents the total station 200 from erroneously detecting a sign 31 as a target and capturing it, or from erroneously detecting a curved mirror 32 or a mirror image of a reflecting prism reflected on the glass surface 31 as a target and capturing it.

[0093] 2 shows only one worker, there may be multiple workers carrying reflecting prisms, with the first worker taking measurements, then the second worker taking measurements, etc. In this case, when moving from step S209 to step S201, the search direction is changed to search for the target (reflecting prism). At this time, there is a risk of a problem in which a bright spot other than the target is mistakenly captured as the target, but the above procedure can prevent this problem from occurring.

[0094] (superiority) According to this embodiment, it is possible to prevent the problem of erroneously detecting a bright spot other than the target as the target. In addition, although the above-mentioned erroneous detection can also occur due to a mirror image of the target on a reflective surface, by acquiring information on the reflective surface, it is possible to prevent erroneous detection of the target caused by the reflective surface during another survey.

[0095] 2. Second embodiment The "position information of non-target reflectors" acquired in step S107 of Fig. 5 can also be used for laser scanning. Typically, the process of Fig. 5 is performed multiple times by changing the installation position of the laser scanning device 100. This is to reduce blind spots in the laser scan. In this case, the process of Fig. 5 is repeated for the second and subsequent laser scans, and the process of step S103 at this time refers to the position information of non-target high-brightness points that has already been acquired.

[0096] 3. Third embodiment 5 is generally performed multiple times by changing the position (machine point) of the laser scanning device 100. This is to minimize the number of points in the blind spots of the laser scan. Therefore, the "position information of non-target reflectors" obtained in step S107 is usually obtained for each of multiple machine points (positions of the viewpoint of the laser scan).

[0097] Therefore, by comparing and integrating the "position information of non-target reflectors" obtained at different machine points, the reliability and validity of the "position information of non-target reflectors" can be improved.

[0098] "Positional information of non-target reflectors" includes positional information of highly efficient reflective surfaces that mistakenly recognize directly reflected light as a target, and positional information of highly efficient reflective surfaces that reflect mirror images. The optical conditions of the former reflective surfaces differ depending on the position of the viewpoint (mechanical point) due to differences in the incident and reflection angles, so by integrating "positional information of non-target reflectors" when the viewpoint position is changed, it is possible to further enhance the positional information of reflectors that may be mistakenly recognized as targets.

[0099] On the other hand, if detection is performed from a single scan, the latter reflective surface that reflects the mirror image may be erroneously detected. That is, in the method whose principle is shown in Figure 7, high-intensity points that can be considered as mirror images of reflective prisms are identified, and the position of reflective surface A is calculated based on these. In other words, reflective surface A that reflects the mirror image is not measured directly. This is because reflected light cannot be obtained from mirror surfaces that are not directly facing, making distance measurement impossible. For this reason, depending on how high-intensity points that are not reflective prisms are selected, there is a possibility that a non-existent reflective surface A may be calculated.

[0100] Therefore, the reliability of the reflective surface on which the mirror image is reflected is evaluated by comparing the position data of the reflective surface on which the mirror image is reflected obtained from multiple machine points. For example, a reflective surface on which a mirror image obtained in common from scan data at multiple machine points is reflected is considered to have high reliability. On the other hand, a reflective surface on which a mirror image obtained only from scan data at one machine point is reflected is considered to have low reliability.

[0101] Then, in step S203 of Fig. 6, the position data of the "reflecting surface on which the mirror image is reflected" having high reliability is unconditionally adopted, but the position data of the "reflecting surface on which the mirror image is reflected" having low reliability is restricted to not be used unless the position of the machine point to be used is close to the machine point that obtained the "reflecting surface on which the mirror image is reflected." This increases the reliability of the determination in step S204 of Fig. 6.

[0102] Furthermore, the position data of the "reflecting surface on which the mirror image is reflected" obtained from a specific machine point is position data within a narrow range of the reflecting surface on which the mirror image is reflected. Here, the position data of the "reflecting surface on which the mirror image is reflected" obtained from multiple machine points, which can be considered to be the same reflecting surface, has a distribution in the surface direction because the position of the mirror image on the reflecting surface changes. Therefore, position data relating to the distribution state of the surface of the "reflecting surface on which the mirror image is reflected" can be obtained. For example, position data corresponding to the shape and extent of the reflecting surface of the convex mirror 32 in Figure 1 can be obtained. Therefore, the reliability of the position data of the "reflecting surface on which the mirror image is reflected" can be improved.

[0103] 4. Fourth Embodiment When using the position data of the "reflective surface on which the mirror image is reflected," all distance measurement data that is farther than the position data of the "reflective surface on which the mirror image is reflected" within a specific range centered on the position data is determined to be a mirror image, as viewed from the machine point used at that time.

[0104] For example, consider the case of Figure 1. Here, position information of the convex mirror 32 is obtained in step S107 of Figure 5. At this time, position information of the entire convex mirror 32 is not necessarily obtained. This is because the above position information is based on the reflection position of the mirror image generated by the convex mirror 32 in the processing of Figure 5.

[0105] Therefore, within a specific range centered on the position of the convex mirror 32 as seen from the laser scanning device 100 (this position is obtained in step S203), for example, within a range of a radius of 50 cm from the center, all bright points farther than the position of the convex mirror 32 are determined to be mirror images. This prevents the problem of erroneously detecting points of the mirror image reflected on the convex mirror 32 as bright points of directly reflected light. Here, the apparent size of the convex mirror 32 may be detected by photographing with a camera, and the above-mentioned specific range may be set.

[0106] When this example is implemented, identification data for identifying the "reflective surface reflecting a mirror image" is stored in the "non-target reflector position information storage unit" 107 in Fig. 3 or in another storage unit in association with the position data of the "reflective surface reflecting a mirror image" obtained by the method of Fig. 7. This stored information is used to eliminate or identify as defective point cloud data obtained from the direction of the "reflective surface reflecting a mirror image" when creating point cloud data in step S109.

[0107] As shown in FIG. 1, the point cloud data relating to the mirror image is position data measured when there is a reflection point in a direction other than the intended direction, and is data that erroneously measures the position of the surveyed object. According to this embodiment, the point cloud data relating to the mirror image can be excluded from the point cloud data obtained by laser scanning, thereby improving the accuracy of the finally obtained point cloud data. For example, the accuracy of the point cloud data of the scanned object obtained in step 109 of FIG. 5 can be improved.

[0108] 5. Fifth Embodiment In step S101 of Fig. 5, a full-circle scan or a scan limited to a specific range is performed. Then, in step S105, a dimming scan is performed on the same range as in step S101. After the dimming scan, step S102 is performed again to re-extract relatively high brightness points (bright points of the scanning light reflected from a reflector with high reflectivity). At this time, a threshold value according to the dimming scan conditions is used.

[0109] In the dimming scan, the scan conditions are adjusted so that the light receiving elements of the laser scanning device 100 are not saturated by the scanning light reflected from the target with high reflectivity. Therefore, by extracting the high-brightness points again after the dimming scan, the position information can be obtained with higher accuracy. This improves the accuracy of the position information of the non-target reflectors obtained in step S107. [Explanation of symbols]

[0110] 100...laser scanning device, 11...tripod, 12...base unit, 13...horizontal rotation unit, 14...vertical rotation unit, 31...sign, 32...convex mirror, 33...glass surface, 41...worker, 42...reflecting prism, 200...total station.

Claims

1. a high-brightness point detection unit that detects, as high-brightness points, bright points whose reflected light intensity exceeds a threshold from laser scan data for an area including the surveying target; a determination unit that determines whether the bright spot is a bright spot of light directly reflected from the surveying target; a storage unit that stores position information of the reflector of the high brightness point that is determined not to be a direct reflection from the survey target in the determination; A surveying data processing device comprising:

2. The bright spots form a plurality of clusters, 2. A surveying data processing device according to claim 1, wherein the judgment is made based on a comparison of the shape and dimensions of the surveying target acquired in advance with the shape and dimensions of the reflector of the bright spot obtained from the point cloud that constitutes the group.

3. The bright spot determined not to be a direct reflection from the surveying target is a mirror image of the surveying target reflected on the reflector, a distance measurement value L1 of the bright spot determined not to be a direct reflection from the survey target; a distance measurement value L2 of the bright spot determined to be direct reflected light from the survey target; The angle between the vector related to L1 and the vector related to L2, The direction of the bright spot that is determined not to be a direct reflection from the survey target; The position of the reflector on which the mirror image is reflected is determined based on the 2. A surveying data processing device according to claim 1, wherein the mirror image is obtained by searching for a set of bright points that are the same as or can be considered to be the same as the distribution of bright points of the laser scanning light reflected from the surveying target.

4. Detecting bright points with reflected light intensities exceeding a threshold as high-bright points from laser scan data for an area including the surveying target; determining whether the bright spot is a bright spot of light directly reflected from the survey target; storing position information of the reflector of the bright spot that is determined not to be a direct reflection from the survey target in the determination; performing an optical scan of the survey target or another survey target in an area overlapping the area where the laser scan was performed; Detecting bright points having a reflected light intensity exceeding a threshold as high-bright points from the optical scan data; A surveying data processing method in which the direction of the bright spot is compared with the direction of the reflector to determine whether the bright spot is reflected light from the surveying target or another surveying target.

5. A program to be read and executed by a computer, Computer a high-brightness point detection unit that detects, as high-brightness points, bright points whose reflected light intensity exceeds a threshold from laser scan data for an area including the surveying target; a determination unit that determines whether the bright spot is a bright spot of light directly reflected from the surveying target; a storage unit that stores position information of the reflector of the high brightness point that is determined not to be a direct reflection from the survey target in the determination; A surveying data processing program that functions as a

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