Measurement method and measurement system

Abstract

The invention provides a measurement method and a measurement system, and relates to the technical field of measurement. The measurement method comprises the following steps of: S1, aligning shooting centers of a plurality of photogrammetric assemblies with a reference point; in the step S2, a conversion relation between a photogrammetry assembly coordinate system and a base station coordinate system is calibrated; in the step S3, intersection measurement is carried out on the to-be-measured point, and coordinates of the reference point and the to-be-measured point in the base station coordinate system are calculated; s4, calculating the coordinates of the reference point and the to-be-measured point in the world coordinate system; in the step S5, the control assembly is used for controlling the rotating assembly to drive the photogrammetry assemblies to rotate until the shooting centers of the multiple photogrammetry assemblies are aligned with the point to be measured; a new reference point is determined in the step S6; and the steps S3-S6 are repeated in the step S7, so that the coordinates of all the to-be-measured points in the world coordinate system are calculated, automatic tracking measurement of the multiple to-be-measured points can be achieved, the photogrammetry assembly can be controlled to rotate, and the shooting range of the photogrammetry assembly can be expanded.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and in particular to a measurement method and a measurement system. Background Art

[0002] In the development of precision measurement and positioning technology, dual-base spatial positioning systems have become a key technology and are widely used in various high-precision measurement tasks. These systems typically use two cameras as dual base stations to measure the spatial coordinates of a target object, such as pre-defined key points on nuclear power equipment, nuclear power pipelines, and nuclear power construction tracks.

[0003] The dual cameras in existing dual-base spatial positioning systems are fixed, that is, the dual cameras are fixed at both ends of the same horizontal bar. When measuring, it is necessary to first arrange reference points with known coordinates in the control field and determine the position of each target in the control field based on the field of view of the dual cameras. Then, the dual cameras are used to perform intersection measurement on the reference points to calibrate the camera positions. Then, the dual cameras are used to perform intersection measurement on each target to measure the position of each target relative to the reference points, thereby determining the coordinates of each target.

[0004] However, during nuclear engineering construction, the control field environment is complex, and targets are easily obscured. This requires moving the dual cameras to bring the targets within their range. Any movement requires recalibration, complicating the measurement process and reducing efficiency. Furthermore, fixed dual cameras have a limited range, often only supporting measurement of targets within the same control field. Expanding the control field requires adding base stations and reference points, a significant workload. Summary of the Invention

[0005] The purpose of the present invention is to provide a measurement method and system to alleviate the technical problems existing in the prior art, such as the fixed position of the dual-base station spatial positioning system, the need to move the dual cameras when the target object is obscured, and then the position of the dual cameras needs to be recalibrated, resulting in a complicated measurement process and low measurement efficiency. In addition, the shooting range of the fixed dual cameras is limited. If the control field range is increased, more base stations and reference points must be added, resulting in an increased workload.

[0006] In a first aspect, the present invention provides a measurement method, comprising: S1: Arrange a reference point and multiple points to be measured in a control field, install multiple photogrammetric components on multiple rotating components in a one-to-one correspondence, align the shooting centers of the multiple photogrammetric components with the reference points, and ensure that at least one point to be measured is within the shooting range of the multiple photogrammetric components; S2: Select the coordinate system of one of the photogrammetric components as the base station coordinate system, use multiple photogrammetric components to photograph the reference points and obtain coordinate information, and calibrate the conversion relationship between the coordinate system of each photogrammetric component and the base station coordinate system based on the measurement results; S3: Using multiple photogrammetric components to photograph the points to be measured within their photographing range and obtain coordinate information, using a control component to receive the coordinate information obtained by each photogrammetric component, and performing intersection measurement based on the conversion relationship between the coordinate system of each photogrammetric component and the base station coordinate system to calculate the coordinate information of the reference point and the point to be measured in the base station coordinate system; S4: Based on the coordinate information of the reference point and the point to be measured in the base station coordinate system and the conversion relationship between the base station coordinate system and the world coordinate system preset in the control component, the control component is used to calculate the coordinates of the reference point and the point to be measured in the world coordinate system; S5: Calculating a relative angle between the reference point and the point to be measured based on the coordinates of the reference point and the point to be measured, and causing the control component to control the multiple rotating components based on the relative angle to respectively drive the photogrammetric components thereon to rotate until the shooting centers of the multiple photogrammetric components are aligned with the point to be measured and the next point to be measured is within the shooting range of the multiple photogrammetric components; S6: using the point to be measured that is aligned with the shooting center of the multiple photogrammetry components as a new reference point; S7: Repeat steps S3-S6 until the coordinates of all the points to be measured in the world coordinate system are calculated.

[0007] In an optional embodiment, camera intrinsic parameters and camera extrinsic parameters are preset in the photogrammetry component, so that the photogrammetry component obtains coordinate information based on the camera intrinsic parameters, camera extrinsic parameters and the images captured by the camera.

[0008] In an optional embodiment, the camera intrinsic parameters include lens radial distortion parameters, lens decentering distortion parameters, image plane distortion parameters and internal orientation element error parameters, and the camera extrinsic parameters include position parameters and posture parameters of the photogrammetry component in the world coordinate system.

[0009] In an optional embodiment, in step S4, error compensation parameters are preset in the control component, and based on the error compensation parameters, the coordinate information of the reference point and the point to be measured in the base station coordinate system, and the conversion relationship between the base station coordinate system and the world coordinate system, the coordinates of the reference point and the point to be measured in the world coordinate system are calculated.

[0010] In an optional embodiment, the rotating component is a theodolite, and the error compensation parameters include a vertical axis tilt error of the rotating component, an eccentric amplitude of the aiming portion of the rotating component, and an eccentric phase of the aiming portion of the rotating component.

[0011] In an optional embodiment, the error compensation parameter is calculated by actually measuring a plurality of known measurement points with known angle values and combining the following two formulas:

[0012] Where, is the eccentricity amplitude of the aiming part of the rotating assembly, is the eccentric phase of the aiming part of the rotating assembly, is the vertical axis tilt error of the rotating assembly; is the vertical angle value of the known measuring point, is the horizontal angle value of the known measuring point; is the vertical angle value obtained when actually measuring a known measuring point. It is the horizontal angle value obtained when actually measuring a known measuring point; is the radius of the horizontal grating in the rotating assembly; is the conversion constant for converting radians into the angle unit "arc seconds", =206264.806".

[0013] In an optional embodiment, an angle measurement module is provided on the rotating component, and the angle measurement module is connected to the control component. The angle measurement module is used to detect the rotation angle of the rotating component during the rotation of the rotating component, and send the detected rotation angle information to the control component; the control component is used to compare the received rotation angle and the calculated relative angle, and control the rotating component to stop rotating when the rotation angle is equal to the relative angle.

[0014] In a second aspect, the present invention provides a measurement system, applying the measurement method as described in any one of the aforementioned embodiments, comprising a control component, a plurality of photogrammetry components, and a plurality of rotation components; The plurality of photogrammetric assemblies are mounted on the plurality of rotating assemblies in a one-to-one correspondence, and the plurality of photogrammetric assemblies and the plurality of rotating assemblies are all connected to the control assembly; the photogrammetric assemblies are used to photograph the reference point and the points to be measured within their photographing range when their photographing centers are aligned with the reference point, and obtain the coordinates of the reference point and the points to be measured in the coordinate system of the photogrammetric assemblies; The control component is preset with a conversion relationship between the base station coordinate system and the world coordinate system. The control component is used to receive coordinate information obtained by multiple photogrammetric components, and perform intersection measurement based on the conversion relationship between the selected base station coordinate system and the coordinate system of each photogrammetric component to calculate the coordinate information of the reference point and the point to be measured in the base station coordinate system, and then calculate the coordinate information of the reference point and the point to be measured in the world coordinate system; The control component is further used to calculate the relative angle between the reference point and the point to be measured based on the coordinate information of the reference point and the point to be measured in the world coordinate system, and control the multiple rotating components to respectively drive the photogrammetric components thereon to rotate based on the relative angle, so that the shooting center of each photogrammetric component is aligned with the point to be measured.

[0015] In an optional embodiment, the control component includes an error compensation parameter module, in which error compensation parameters are preset. The control component is used to calculate the coordinates of the reference point and the point to be measured in the world coordinate system based on the error compensation parameters, the coordinate information of the reference point and the point to be measured in the base station coordinate system, and the conversion relationship between the base station coordinate system and the world coordinate system.

[0016] In an optional embodiment, the rotating assembly includes an upper turntable and a lower turntable, and both the upper turntable and the lower turntable include a rotating output end; The central axis of the rotation output end of the upper turntable is a horizontal axis, the photogrammetric assembly is mounted on the rotation output end of the upper turntable, and the upper turntable is used to drive the photogrammetric assembly to rotate around the central axis of the rotation output end thereof; The central axis of the rotation output end of the lower turntable is a vertical axis. The upper turntable is installed on the rotation output end of the lower turntable. The lower turntable is used to drive the upper turntable and the photogrammetry assembly to rotate around the central axis of its rotation output end.

[0017] The measurement method provided by the present invention includes: S1: arranging a reference point and multiple points to be measured in a control field, installing multiple photogrammetric components on multiple rotating components in a one-to-one correspondence, aligning the shooting centers of the multiple photogrammetric components with the reference points, and ensuring that at least one point to be measured is located within the shooting range of the multiple photogrammetric components; S2: selecting the coordinate system of one of the photogrammetric components as the base station coordinate system, using the multiple photogrammetric components to shoot the reference points and obtain coordinate information, and calibrating the conversion relationship between the coordinate system of each photogrammetric component and the base station coordinate system based on the measurement results; S3: using the multiple photogrammetric components to shoot the points to be measured within their shooting ranges and obtain coordinate information, using the control component to receive the coordinate information obtained by each photogrammetric component, and performing intersection measurement based on the conversion relationship between the coordinate system of each photogrammetric component and the base station coordinate system. , to calculate the coordinate information of the reference point and the point to be measured in the base station coordinate system; S4: based on the coordinate information of the reference point and the point to be measured in the base station coordinate system, and based on the conversion relationship between the base station coordinate system and the world coordinate system preset in the control component, use the control component to calculate the coordinates of the reference point and the point to be measured in the world coordinate system; S5: calculate the relative angle between the reference point and the point to be measured according to the coordinates of the reference point and the point to be measured, and enable the control component to control the multiple rotating components to respectively drive the photogrammetric components thereon to rotate based on the relative angle, until the shooting centers of the multiple photogrammetric components are aligned with the point to be measured, and the next point to be measured is located within the shooting range of the multiple photogrammetric components; S6: the point to be measured aligned with the shooting centers of the multiple photogrammetric components is used as a new reference point; S7: repeat steps S3-S6 until the coordinates of all the points to be measured in the world coordinate system are calculated. The measurement method provided by the present invention can be used for measuring the three-dimensional spatial dimensions of nuclear equipment such as reactor shells during the construction of nuclear engineering projects, and can also be used for posture measurement and correction of nuclear equipment, or for measurement operations in tasks such as welding deformation detection of nuclear power plant main pipelines and installation and adjustment of high-precision tracks in nuclear power plants. When measuring target objects such as the above-mentioned nuclear equipment, main pipelines and high-precision tracks, a control field can be first established in the space around the above-mentioned target objects, and then step S1 of the measurement method of the present invention can be performed in the control field. Specifically, when performing step S1, a reference point with known coordinates can be first arranged in the control field, and multiple key points can be determined on the target object based on the shape and posture of the target object as multiple points to be measured, and then multiple rotating components and the photogrammetric components thereon can be arranged at intervals in the control field. At this time, each photogrammetric component can serve as a base station. Correspondingly, the measurement method provided by the present invention is based on multiple base stations to perform spatial positioning measurement of the target object.The photogrammetric component may be a digital close-range photogrammetric component including a camera. In this case, the photogrammetric component has image recognition and processing capabilities and is capable of acquiring the coordinates of a reference point or a point to be measured in its coordinate system based on the captured image. The rotation component may be a theodolite including a motor, a horizontal turntable, and a vertical rotation axis. During the arrangement of the rotation component and the photogrammetric component in step S1, the shooting center of each photogrammetric component must be aligned with the reference point. That is, the shooting center of each photogrammetric component is located on the same straight line as the reference point, and the reference point is located within the shooting range of multiple photogrammetric components. Furthermore, at least one point to be measured must be located on the periphery of the reference point to ensure that at least one point to be measured is within the shooting range of multiple photogrammetric components. Then, step S2 can be performed. In step S2, the coordinate system of one of the photogrammetric components is selected as the base station coordinate system. At the same time, multiple photogrammetric components are used to photograph the reference point and obtain coordinate information. Since the coordinates of the reference point are known, the conversion relationship between the coordinate system of each photogrammetric component and the base station coordinate system can be calibrated based on the coordinate information of the reference point obtained by each photogrammetric component. It should be noted that in step S2, the conversion relationship between the coordinate system of each photogrammetric component and the base station coordinate system can be calibrated in real time using the control component. Then, step S3 is performed. In step S3, the positions of the multiple photogrammetric components are kept fixed, and the multiple photogrammetric components are used to photograph the points to be measured within their shooting range and obtain coordinate information. The control component can then receive the coordinate information of the points to be measured obtained by each photogrammetric component through wired or wireless communication, and perform intersection measurement based on the conversion relationship between the coordinate system of each photogrammetric component and the base station coordinate system, thereby calculating the coordinate information of the reference point and the points to be measured in the base station coordinate system. To improve measurement efficiency, the photographing and intersection measurement process of the target point in step S3 can be performed simultaneously with the photographing and intersection measurement process of the reference point in step S2. Then, step S4 is performed. In step S4, the coordinate information of the reference point and the target point in the base station coordinate system calculated by the control component, and the conversion relationship between the base station coordinate system and the world coordinate system preset in the control component, are used to calculate the coordinates of the reference point and the target point in the world coordinate system. At this point, the world coordinates of the first target point around the reference point are calculated. Subsequent steps are then performed to measure the world coordinates of the remaining target points around the reference point. Specifically, in step S5, the relative angle between the reference point and the target point is calculated based on the coordinates of the reference point and the first target point. Here, the coordinates of the reference point and the first target point can be the coordinates of the reference point and the first target point in the world coordinate system calculated in step S4. Then, based on the calculated relative angle, the control component controls the multiple rotating components to rotate the photogrammetric components thereon until the shooting center of each photogrammetric component is aligned with the first target point and the next target point is within the shooting range of each photogrammetric component.Since the photogrammetric component of the present invention can rotate under the drive of the rotating component, its shooting range is wider and more flexible. At this time, the position of the measured point can be adjusted in advance to prevent the measured point from being blocked and unable to enter the shooting range of the photogrammetric component. Therefore, compared with the fixed camera in the prior art, the measurement process of the measurement method provided by the present invention is more flexible and less likely to cause the target object to be easily blocked. Therefore, there is no need to move the position of the photogrammetric component, which can effectively simplify the measurement process and improve measurement efficiency. After completing step S5, step S6 is performed to use the first measured point as a new reference point, and finally step S7 is performed to repeat steps S3-S6 to calculate the coordinates of all the measured points in the world coordinate system. After obtaining the coordinates of all the measured points in the world coordinate system, the coordinates of each key point on the target object in space can be determined, thereby realizing the spatial positioning of the target object. It can be judged whether the three-dimensional spatial dimensions of nuclear equipment such as the reactor shell meet the production requirements, whether the pipe body of the nuclear power plant main pipeline is deformed after welding, and whether the high-precision track of the nuclear power plant is installed in place. It can be seen that the measurement method provided by the present invention can also realize automatic tracking measurement of the remaining points to be measured after the first point to be measured through steps S3-S7, which can not only further effectively improve the measurement efficiency, but also can adjust the position of the photogrammetry component in real time to improve its measurement accuracy.

[0018] Compared to the prior art, the measurement method provided by the present invention, through the use of a rotation component in step S1, can expand the shooting range of each photogrammetric component, thereby flexibly adjusting the relative position between the photogrammetric component and the measured point, without having to move the photogrammetric component, effectively simplifying the measurement process and thus improving measurement efficiency. Furthermore, if the control field range is increased, the photogrammetric component can be rotated so that the photogrammetric component can capture the measured points within the increased control field, eliminating the need for additional base stations and reference points, effectively reducing the workload. Furthermore, the measurement method provided by the present invention, through steps S1-S7, can achieve automatic tracking measurement of multiple measured points within the control field, further improving measurement efficiency and allowing the relative position between the photogrammetric component and the reference point to be adjusted in real time during the automatic tracking measurement process, thereby effectively improving the shooting accuracy and intersection measurement accuracy of the photogrammetric component and reducing measurement errors.

[0019] The measurement system provided by the present invention applies the above-mentioned measurement method, and the measurement system includes a control component, multiple photogrammetric components and multiple rotation components; the multiple photogrammetric components are installed on the multiple rotation components in a one-to-one correspondence, and the multiple photogrammetric components and the multiple rotation components are all connected to the control component; the photogrammetric component is used to shoot the reference point and the point to be measured within its shooting range when its shooting center is aligned with the reference point, and obtain the coordinates of the reference point and the point to be measured in the coordinate system of the photogrammetric component; the control component is preset with a conversion relationship between the base station coordinate system and the world coordinate system, and the control component is used to receive multiple The coordinate information obtained by the photogrammetric component and the intersection measurement based on the conversion relationship between the selected base station coordinate system and the coordinate system of each photogrammetric component are used to calculate the coordinate information of the reference point and the point to be measured in the base station coordinate system, and then calculate the coordinate information of the reference point and the point to be measured in the world coordinate system. The control component is also used to calculate the relative angle between the reference point and the point to be measured based on the coordinate information of the reference point and the point to be measured in the world coordinate system, and control the multiple rotating components to respectively drive the photogrammetric components thereon to rotate based on the relative angle so that the shooting center of each photogrammetric component is aligned with the point to be measured. The measurement system provided by the present invention applies the above-mentioned measurement method, and thus the measurement system has the same beneficial effects as the above-mentioned measurement method. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A flow chart of a measurement method provided in an embodiment of the present invention; Figure 2 A central perspective projection diagram of the imaging process of the photogrammetry component provided by an embodiment of the present invention; Figure 3 A cross ratio definition diagram in the perspective projection transformation of the photogrammetry component provided in an embodiment of the present invention; Figure 4 This is a schematic structural diagram of a rotation component and a photogrammetry component in a measurement system provided by an embodiment of the present invention.

[0022] Icon: 1-Photogrammetry component; 2-Rotation component; 20-Upper turntable; 21-Lower turntable. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0025] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0026] Example: like Figure 1 As shown, the measurement method provided in this embodiment includes the following steps: Step S1: arranging a reference point and a plurality of points to be measured in a control field, installing a plurality of photogrammetric components on a plurality of rotating components in a one-to-one correspondence, aligning the shooting centers of the plurality of photogrammetric components with the reference points, and ensuring that at least one point to be measured is within the shooting range of the plurality of photogrammetric components; Step S2: Select the coordinate system of one of the photogrammetric components as the base station coordinate system, use multiple photogrammetric components to photograph the reference points and obtain coordinate information, and calibrate the conversion relationship between the coordinate system of each photogrammetric component and the base station coordinate system based on the measurement results; Step S3: Using multiple photogrammetric components to photograph the points to be measured within their photographing range and obtain coordinate information, using a control component to receive the coordinate information obtained by each photogrammetric component, and performing intersection measurement based on the conversion relationship between the coordinate system of each photogrammetric component and the base station coordinate system to calculate the coordinate information of the reference point and the point to be measured in the base station coordinate system; Step S4: Based on the coordinate information of the reference point and the point to be measured in the base station coordinate system, and based on the conversion relationship between the base station coordinate system and the world coordinate system preset in the control component, the coordinates of the reference point and the point to be measured in the world coordinate system are calculated by the control component; Step S5: Calculating the relative angle between the reference point and the point to be measured based on their coordinates, and causing the control component to control the multiple rotating components to respectively drive the photogrammetric components thereon to rotate based on the relative angle until the photographic centers of the multiple photogrammetric components are aligned with the point to be measured, and the next point to be measured is within the photographic range of the multiple photogrammetric components; Step S6: using the point to be measured that is aligned with the shooting center of the multiple photogrammetry components as a new reference point; Step S7: Repeat steps S3-S6 until the coordinates of all the points to be measured in the world coordinate system are calculated.

[0027] The measurement method provided in this embodiment can be used to measure the three-dimensional dimensions of nuclear equipment, such as reactor shells, during nuclear engineering construction. It can also be used for measuring and correcting the posture of nuclear equipment, or for measuring tasks such as detecting welding deformation of nuclear power plant main pipelines and installing and adjusting high-precision rails in nuclear power plants. When measuring target objects such as these nuclear equipment, main pipelines, and high-precision rails, a control field can be first established in the space surrounding the target object, and then step S1 of the measurement method of this embodiment can be performed within the control field.

[0028] Specifically, when performing step S1, reference points with known coordinates can be arranged in the control field first, and multiple key points can be determined on the target object based on the shape and posture of the target object as multiple points to be measured. Then, multiple rotating components and the photogrammetric components thereon can be arranged at intervals in the control field. At this time, each photogrammetric component can serve as a base station. Correspondingly, the measurement method provided in this embodiment is based on multiple base stations to perform spatial positioning measurement of the target object.

[0029] The measurement method provided in this embodiment can be combined with Figure 4 The rotation component 2 and the photogrammetry component 1 shown are carried out, wherein the photogrammetry component 1 can adopt a digital close-range photogrammetry component 1 including a camera, which has image recognition and processing functions, can identify the measurement target from multiple angles and can take pictures at a high frequency, and obtain the coordinates of the reference point or the point to be measured in its coordinate system based on the photographed image, as well as the scale information and posture information of the measurement target; the rotation component 2 can adopt a theodolite including a motor, a horizontal turntable and a vertical rotation axis. At this time, the rotation component 2 can rotate in the horizontal and pitch directions.

[0030] During the arrangement of the rotation component 2 and the photogrammetric component 1 in step S1, the shooting center of each photogrammetric component 1 needs to be aligned with the reference point, that is, the shooting center of each photogrammetric component 1 is located on the same straight line as the reference point and the reference point is located within the shooting range of multiple photogrammetric components 1. At the same time, at least one point to be measured needs to be located on the periphery of the reference point to ensure that at least one point to be measured is located within the shooting range of multiple photogrammetric components 1.

[0031] Then step S2 can be performed. In step S2, the coordinate system of one of the photogrammetric components 1 is selected as the base station coordinate system, and multiple photogrammetric components 1 are used to shoot the reference point and obtain coordinate information. Since the coordinates of the reference point are known, the conversion relationship between the coordinate system of each photogrammetric component 1 and the base station coordinate system can be calibrated based on the coordinate information of the reference point obtained by each photogrammetric component 1. It should be noted that in step S2, the control component can be used to calibrate the conversion relationship between the coordinate system of each photogrammetric component 1 and the base station coordinate system in real time.

[0032] Then, step S3 is performed. In step S3, the positions of the multiple photogrammetric components 1 are kept fixed, and the multiple photogrammetric components 1 are used to photograph the points to be measured within their shooting range and obtain coordinate information. Then, the control component can receive the coordinate information of the points to be measured obtained by each photogrammetric component 1 through wired or wireless communication, and perform intersection measurement calculations based on the conversion relationship between the coordinate system of each photogrammetric component 1 and the base station coordinate system to calculate the coordinate information of the reference point and the points to be measured in the base station coordinate system. To improve measurement efficiency, the photography and intersection measurement processes of the points to be measured in step S3 can be performed simultaneously with the photography and intersection measurement processes of the reference points in step S2. The intersection measurement process can use the existing camera RT forward intersection technology or the dual theodolite intersection angle measurement.

[0033] Then proceed to step S4. In step S4, the coordinate information of the reference point and the point to be measured in the base station coordinate system calculated by the control component, as well as the conversion relationship between the base station coordinate system and the world coordinate system preset in the control component, are used to calculate the coordinates of the reference point and the point to be measured in the world coordinate system. At this point, the world coordinates of the first point to be measured around the reference point can be calculated.

[0034] Then, subsequent steps are performed to measure the world coordinates of the remaining points to be measured around the reference point. Specifically, in step S5, the relative angle between the reference point and the point to be measured is calculated based on the coordinates of the reference point and the first point to be measured. Here, the coordinates of the reference point and the first point to be measured can be the coordinates of the reference point and the first point to be measured in the world coordinate system calculated in step S4. Then, based on the relative angle calculated above, the control component controls the multiple rotating components 2 to respectively drive the photogrammetric components 1 thereon to rotate until the shooting center of each photogrammetric component 1 is aligned with the first point to be measured and the next point to be measured is within the shooting range of each photogrammetric component 1.

[0035] Because the photogrammetric assembly 1 in this embodiment can rotate driven by the rotating assembly 2, its shooting range is wider and more flexible. The position of the point to be measured can be pre-adjusted to prevent it from being obscured and unable to enter the shooting range of the photogrammetric assembly 1. Therefore, compared to the fixed cameras in the prior art, the measurement method provided by this embodiment is more flexible and less prone to the situation where the target object is easily obscured. This eliminates the need to move the position of the photogrammetric assembly 1, effectively simplifying the measurement process and improving measurement efficiency. To ensure the shooting range of the photogrammetric assembly 1, the rotating assembly 2 can rotate horizontally within a range of 0° to 360°, and the pitch rotation range of the rotating assembly 2 can be ±120°.

[0036] After completing step S5, step S6 is performed, using the first test point as the new reference point. Finally, step S7 is performed, repeating steps S3-S6 to calculate the coordinates of all test points in the world coordinate system. Once the coordinates of all test points in the world coordinate system are obtained, the spatial coordinates of key points on the target object can be determined, thereby achieving spatial positioning of the target object. This allows for determining whether the three-dimensional dimensions of nuclear equipment such as reactor shells meet production requirements, whether the main pipeline of a nuclear power plant is deformed after welding, and whether the high-precision track of the nuclear power plant is properly installed.

[0037] It can be seen that the measurement method provided in this embodiment can also achieve automatic tracking measurement of the remaining points to be measured after the first point to be measured through steps S3-S7. This not only further effectively improves measurement efficiency, but also allows the position of the photogrammetry component 1 to be adjusted in real time to improve its measurement accuracy. After experimental verification, the measurement method provided in this embodiment can improve the measurement accuracy to 15μm + 20μm / m (where 15μm is a fixed error and 20μm / m is a proportional error) during the automatic tracking measurement process through the forward intersection measurement technology and multi-base station joint calibration technology. It is applicable to various high-precision measurement scenarios. In addition, the measurement method provided in this embodiment can effectively shorten the time from collecting and measuring the points to displaying the measurement results through the cooperation between the photogrammetry component 1 and the control component, and can control the response time to less than two seconds, effectively meeting the needs of real-time measurement.

[0038] Compared to the prior art, the measurement method provided in this embodiment, through the use of a rotation component 2 in step S1, can expand the imaging range of each photogrammetric component 1, thereby flexibly adjusting the relative position between the photogrammetric component 1 and the measured point, eliminating the need to move the photogrammetric component 1. This effectively simplifies the measurement process and thus improves measurement efficiency. Furthermore, if the control field range is increased, the photogrammetric component 1 can be rotated to capture the increased number of measured points within the control field, eliminating the need for additional base stations and reference points, effectively reducing the workload. Furthermore, the measurement method provided in this embodiment, through steps S1-S7, can achieve automatic tracking measurement of multiple measured points within the control field. This not only further improves measurement efficiency, but also allows the relative position between the photogrammetric component 1 and the reference point to be adjusted in real time during the automatic tracking measurement process, effectively improving the imaging accuracy of the photogrammetric component 1 and reducing measurement errors.

[0039] In addition, since the measurement method provided in this embodiment can effectively improve measurement efficiency, compared with the existing technology, the measurement method provided in this embodiment can also reduce the interference of environmental factors (such as light and temperature) caused by long measurement time on the measurement results, thereby effectively resisting interference from the external environment and further improving measurement accuracy.

[0040] In this embodiment, the photogrammetric assembly 1 is an image processing system based on an image sensor, consisting of an optical system (lens), an image acquisition unit, an image data preprocessing unit, an interface unit, and a power supply unit. Because the image acquisition unit, image data preprocessing unit, and power supply unit generate heat during the photogrammetric measurement process, which can affect measurement accuracy, this embodiment preferably incorporates a heat dissipation structure into the photogrammetric assembly 1. This structure effectively reduces the interference of heat generated by the photogrammetric assembly 1 on the measurement results, further improving measurement accuracy. The heat dissipation structure can reduce thermal resistance by shortening the heat transfer path, increasing the conduction cross-sectional area, and enhancing thermal conductivity.

[0041] The camera used in the photogrammetry component 1 is typically based on a stable solid-state image sensor, and its performance parameters have a direct impact on the measurement results. Therefore, in this embodiment, the digital camera used in the photogrammetry component 1 is preferably calibrated. The camera's internal orientation elements and lens optical distortion coefficients are collectively referred to as camera intrinsic parameters, while the external orientation elements are referred to as camera extrinsic parameters. These camera intrinsic and extrinsic parameters can be preset in the photogrammetry component, allowing the component to obtain coordinate information based on these camera intrinsic and extrinsic parameters and the images it captures.

[0042] Among them, the camera internal parameters include lens radial distortion parameters, lens eccentricity distortion parameters, image plane distortion parameters and internal orientation element error parameters; the camera external parameters include the position parameters and posture parameters of the photogrammetry component 1 in the world coordinate system.

[0043] Regarding radial distortion parameters, radial distortion is the radial deviation of the image point. Radial distortion is symmetrical, and while the center of symmetry may not coincide exactly with the principal point, the principal point is generally considered the center of symmetry. Radial distortion can be positive or negative, with positive deviation outward from the principal point and negative deviation inward from the principal point. Wide-angle lenses (f < 50mm) typically exhibit negative distortion, while standard lenses (f = 50mm) exhibit both positive and negative distortion. Medium-telephoto lenses (80mm < 150mm) and telephoto lenses (f > 150mm) typically exhibit positive distortion. Standard lenses exhibit minimal distortion, while shorter (or longer) focal lengths exhibit greater distortion.

[0044] The radial distortion can be expressed by the following odd-order polynomial:

[0045] Decompose it into the x-axis and y-axis of the image plane coordinate system, then we have:

[0046] Where: K1, K2, K3 are radial distortion coefficients; .

[0047] Formula (2) is called Gaussian radial distortion. Since the solution process of Gaussian radial distortion is an existing technology, its specific solution process will not be described here.

[0048] Regarding the lens eccentricity distortion parameter: Lens eccentricity distortion is the eccentricity distortion caused by the center of the lens group deviating from the main optical axis. The eccentricity distortion causes both radial deviation and tangential deviation of the image point. Its expression is as follows:

[0049] Decompose it into the x-axis and y-axis of the image plane coordinate system, then we have:

[0050] Where: P1 and P2 are eccentricity distortion coefficients.

[0051] The eccentric distortion is much smaller in quantity than the radial distortion. Since the solution process of the eccentric distortion is also an existing technology, the specific solution process will not be described here.

[0052] Regarding the distortion parameters within the image plane: The distortion within the image plane is the planar distortion of the image point within the image plane caused by the A / D conversion and signal transfer errors caused by the asynchronous sampling clock of the pixels. It can usually be simplified into the length and width scale factors of the pixels and the distortion caused by the non-orthogonality of the x-axis and y-axis of the image plane. Its expression is as follows:

[0053] Where: b1 and b2 are the distortion coefficients in the image plane. Since the process of solving the distortion parameters in the image plane is also an existing technology, the specific solution process will not be repeated here.

[0054] For the interior orientation element error parameter: If the interior orientation element (x0, y0, ) is inaccurate, it will also cause deviations in the image point coordinates. If the principal distance has an error Δ , then the corresponding image point coordinate deviation can be deduced as:

[0055] Adding the error of the principal point (x0, y0), the image point deviation caused by the error of the interior orientation element can be expressed as:

[0056] In summary, the systematic error caused by the intrinsic parameters of the camera at any image point is the sum of the radial distortion, eccentric distortion, distortion in the image plane, and distortion caused by inaccurate internal orientation elements. The coordinate deviation of the image point caused by these intrinsic parameters is called the systematic error of the image point. Combining formula (2), formula (4), formula (5) and formula (7), the systematic error of the image point can be obtained as:

[0057] Taking into account the influence of the image point system error, the collinearity equation can be written as:

[0058] Where: X, Y, Z are the coordinates of the object point; Xs, Ys, Zs are called the exterior orientation elements of the image, which are used to determine the orientation of an image and the projection center in the object coordinate system; is the focal length; is the element of the rotation matrix, and the corresponding relationship is .

[0059] In practical applications, camera intrinsic parameters can also be determined using a test field calibration method. Specifically, a test field is constructed from a large number of control points with known 3D coordinates. The camera to be calibrated is then used to capture calibration images at multiple locations and angles within the test field. The camera intrinsic parameters are then determined using the resection method. This method utilizes a large number of high-precision control points for spatial resection, directly compensating for systematic errors in the image points. Its advantages include relatively accurate correction of systematic errors, simple calculations, minimal requirements for photographic geometry, and minimal influence from correlations between intrinsic and extrinsic parameters, making it possible to evaluate the quality of calibration results.

[0060] The external parameters of the camera can be determined as follows: install a collimating cube on the camera, and place the camera on the rotating assembly 2, so that the X axis of the camera is roughly horizontal with the horizontal axis of the rotating assembly 2, and the Y axis of the camera is roughly horizontal with the vertical axis of the rotating assembly 2; then aim the camera at the reference point in the control field for measurement, and use the rear intersection principle to calculate the position and attitude of the camera; then stick a coding point above the camera lens, and then rotate the camera horizontally and measure every 10° to calculate the coordinates of the point in the control field coordinate system, and then rotate the camera horizontally for one circle to measure multiple coordinate values of the point at multiple positions in the control field coordinate system to fit a circle, and then rotate the camera vertically for one circle to fit another circle. The intersection of the two circle normals is the origin of the coordinate system of the rotating assembly 2, thereby calibrating the coordinate system of the rotating assembly 2; then use the theodolite measurement system to aim at the cube and the control point at the same time to calculate the conversion relationship between the coordinate system of the camera and the coordinate system of the rotating assembly 2.

[0061] Therefore, in the process of calculating the coordinates of the reference point and the point to be measured in the world coordinate system, when considering the intrinsic parameters of the camera, it is necessary to compensate the systematic errors caused by the intrinsic parameters of the camera in the calculation process; when considering the extrinsic parameters of the camera, it is necessary to convert the coordinate system of the camera and the coordinate system of the rotating component 2, and then use the coordinate system of the rotating component 2 as the coordinate system of the photogrammetry component 1 for calculation.

[0062] In this embodiment, in step S4, error compensation parameters can also be preset in the control component, and based on the error compensation parameters, the coordinate information of the reference point and the point to be measured in the base station coordinate system, and the conversion relationship between the base station coordinate system and the world coordinate system, the coordinates of the reference point and the point to be measured in the world coordinate system are calculated.

[0063] The rotating assembly 2 will inevitably cause errors during the manufacture and use of the instrument, so this part of the error needs to be taken into account in the calculation process to further improve the measurement accuracy. Based on this, the present embodiment preferably presets error compensation parameters in the control assembly.

[0064] The rotating component 2 is a theodolite. Based on the structure of the theodolite, the errors can be divided into grating error, reading system error, axis and eccentricity error, and inclination sensor error.

[0065] Grating errors include diameter error, grating tilt error, and grating deformation error. Diameter error is the error in the dial diameter produced due to workmanship. This error can be automatically eliminated by measuring six or more times as required, and therefore does not need to be included in the calculation. Grating tilt error refers to the disc not being perpendicular to the vertical axis and the optical axis of the reading system not being perpendicular to the disc. This error is negligible and does not need to be included in the calculation. Grating deformation error is the error caused by thermal deformation of the disc. This error can be resolved through heat dissipation and also does not need to be included in the calculation.

[0066] Reading system errors: These include grating eccentricity, incomplete grating orthogonality, and subdivision errors. These errors can be accounted for by averaging the readings and therefore do not need to be factored into the calculation.

[0067] Regarding axis system and eccentricity errors: This error includes axis system error and eccentricity error. Among them, axis system error is caused by the fact that the sighting axis is not perpendicular to the horizontal axis, the horizontal axis is not perpendicular to the vertical axis, and the vertical axis cannot be absolutely plumb during the actual use of the theodolite. This error refers to the measurement error of horizontal and vertical angles caused by the tilt of the axis system during the angle measurement of the theodolite. Eccentricity error is caused by the eccentricity of both the degree plate and the axis system of the theodolite. The eccentricity error is divided into the eccentricity of the angle encoder and the error caused by the eccentricity of the sighting part. The eccentricity of the angle encoder can be eliminated by using the method of diametrically installing the reading head, so it does not need to be included in the calculation process. The error caused by the eccentricity of the sighting part refers to the eccentricity of the theodolite's sighting part and the eccentricity of the horizontal grating. Its influence is relatively large, so it needs to be included in the calculation process. It should be noted that this part of the error is also the main reason why it is difficult to improve the angle measurement accuracy.

[0068] Regarding the error of the inclination sensor: This error refers to the leveling error of the theodolite caused by the inclination sensor. The leveling error will affect the observation results, so it needs to be corrected during the calculation process.

[0069] Based on the above-mentioned axis system and eccentricity errors and inclination sensor errors that need to be corrected, the above-mentioned error compensation parameters may include the vertical axis tilt error of the rotating component 2, the eccentricity amplitude of the aiming part of the rotating component 2 and the eccentricity phase of the aiming part of the rotating component 2. When analyzing the error, the above-mentioned three parameters can be calculated first and pre-set in the control component to form an error correction program, so that the above-mentioned error compensation parameters can be taken into account in the calculation process, thereby improving the accuracy of the coordinate calculation of the final measured point.

[0070] In this embodiment, the calculation process of the error compensation parameter is as follows: The error caused by the vertical axis tilt and the error caused by the horizontal axis tilt are based on the same principle. The tilt of the vertical axis actually causes the horizontal axis to tilt. In terms of value, it only increases the horizontal axis tilt by iv= ×cosβ′ (iv is the horizontal axis tilt angle caused by the vertical axis tilt, is the vertical axis tilt error, β′ is the measured horizontal grating reading), so when correcting the axis system error, it is only necessary to add an error component caused by the vertical axis tilt when correcting the error caused by the horizontal axis tilt, that is, the horizontal axis tilt is regarded as the sum of the original horizontal axis tilt and the vertical axis tilt on the horizontal axis, thus obtaining i total = i+iv=i+ ×cosβ′ (i is the total tilt angle, i is the horizontal axis tilt angle). In reality, the error due to vertical axis tilt and the error due to horizontal axis tilt appear identical, and there's no need to correct them separately; they can be corrected simply by treating them as a component of the horizontal axis tilt.

[0071] When measuring the test point, the existing F1 / F2 method can be used to offset the effects of the collimation axis and the horizontal axis on the measurement angle. The mathematical formula for the error caused by axis tilt is as follows:

[0072] Where: β, α are the accurate horizontal and vertical angle values at the measuring point; , are the horizontal angle value and vertical angle value of the actual measurement at the measuring point; , The horizontal angle error and vertical angle error at the measuring point caused by the inclination of the axis system; in:

[0073]

[0074] Where: is the vertical axis tilt error; Substituting formula (12) into formula (10) and formula (13) into formula (11), we can obtain:

[0075] The calculation process of the eccentricity error in the shaft system and eccentricity error is as follows: The error caused by the eccentricity of the aiming part should be analyzed from both the horizontal angle and the vertical angle. The correction formula for the eccentricity error is as follows:

[0076] Where: , are the horizontal angle error and vertical angle error at the measuring point caused by the eccentricity of the sighting part; e is the eccentricity amplitude of the sighting part of the rotating component 2 (the distance from the eccentricity to the center); η is the eccentricity phase of the sighting part of the rotating component 2; is the radius of the horizontal grating in the rotating assembly 2, which is a known value; is the conversion constant for converting radians into the angle unit "arc seconds", =206264.806".

[0077] When performing error correction, the error correction principle is as follows:

[0078] Where: , is the total horizontal angle error and the total vertical angle error at the measuring point; Taking various factors into consideration, we only need to correct the vertical axis error and eccentricity error, and we should have:

[0079] Substituting formula (12), formula (16) and formula (20) into formula (18), and substituting formula (13), formula (17) and formula (21) into formula (19), the final error correction formula is calculated as:

[0080] in, , The parameters v, e, and η can be directly obtained through measurement readings. By determining the specific values of v, e, and η, error compensation can be performed using formulas (22) and (23). At this point, the values of v, e, and η parameters can be obtained through direct and indirect measurement methods. However, the direct measurement method will introduce new errors caused by defects such as the device's own errors. Therefore, this embodiment preferably uses the indirect calculation method to calculate the v, e, and η parameters.

[0081] The calculation principle of the indirect calculation method is to first regard the system error as a constant value. Correspondingly, the v, e, and η parameters that cause the system error are also constant values. Then, by measuring the angles of multiple measuring points with known angles, the angle measurement values are obtained. Then, the error value between the known angle value and the measured angle value is calculated. At this time, there are multiple error values. Substituting the multiple error values into formula (22) and formula (23) respectively, a linear equation system including three unknowns (v, e, η) can be obtained. Solving the equation system can obtain the v, e, and η parameter values.

[0082] For example, the theodolite in this embodiment is used to perform actual measurements on three measuring points with known angle values. The known angle values of the three measuring points are The corresponding angle values of the three measuring points are , after substituting the known angle value and measured angle value of each measuring point into formula (22) and formula (23), each measuring point can obtain a set of , , The function of the unknown number can be solved by three linear equations (each linear equation contains three unknowns) , , .

[0083] It can be seen that the above error compensation parameters can be calculated by actually measuring multiple known measurement points with known angle values and then combining formula (22) and formula (23). At this time, the meaning of each parameter in the formula is as follows: is the eccentricity amplitude of the aiming part of the rotating component 2, is the eccentric phase of the aiming part of the rotating component 2, is the vertical axis tilt error of the rotating component 2; is the vertical angle value of the known measuring point, is the horizontal angle value of the known measuring point; is the vertical angle value obtained when actually measuring a known measuring point. It is the horizontal angle value obtained when actually measuring a known measuring point; is the radius of the horizontal grating in the rotating component 2; is the conversion constant for converting radians into the angle unit "arc seconds", =206264.806".

[0084] In this embodiment, an angle measurement module can be provided on the rotating component 2, and the angle measurement module is connected to the control component. The angle measurement module is used to detect the rotation angle of the rotating component 2 during the rotation of the rotating component 2, and send the detected rotation angle information to the control component; the control component is used to compare the received rotation angle and the calculated relative angle, and control the rotating component 2 to stop rotating when the rotation angle is equal to the relative angle.

[0085] During use, the angle measurement module can measure the rotation angle of the rotating component 2 in real time and feed back the angle to the control component in real time, so that when the rotation angle of the rotating component 2 is equal to the relative angle between the reference point and the point to be measured in step S5, the control component can be used to promptly control the rotating component 2 to stop rotating, thereby improving the accuracy of establishing the coordinate system of the photogrammetry component 1.

[0086] The angle measurement module can be an angle sensor or a photoelectric encoder. Since an absolute photoelectric encoder does not require a counter, responds promptly and overcomes the cumulative reading error, the angle measurement module in this embodiment preferably uses a high-precision photoelectric absolute encoder.

[0087] To further improve the measurement accuracy and reliability of the angle measurement module, this embodiment also preferably uses a high-precision photoelectric absolute encoder to engrave dark lines on a bright substrate to form a scale, and its basic scale period is 30 μm.

[0088] During the process of the control component controlling the rotation of the rotating component 2, the reading head of the high-precision photoelectric absolute encoder on the rotating component 2 can receive measurement instructions from the control component, and the reading head can calculate the position through two independent methods when receiving the instructions to avoid the risk of failure due to common causes. Therefore, compared with the existing ordinary absolute encoders, the high-precision photoelectric absolute encoder in this embodiment can greatly improve the measurement accuracy.

[0089] To further ensure angle measurement accuracy, this embodiment utilizes a non-contact, open-type grating design for its high-precision photoelectric absolute encoder. This design avoids non-repeatable errors such as connector play, shaft runout, and mechanical hysteresis common in traditional absolute encoders. Tests have shown that the high-precision photoelectric absolute encoder in this embodiment achieves a horizontal and vertical angle measurement accuracy of no greater than 4".

[0090] Furthermore, the rotating assembly 2 can be equipped with a touchscreen compatible with the control assembly. This touchscreen can include buttons for taking photos and other functions to facilitate measurement. Furthermore, the touchscreen can display the coordinates calculated by the control assembly in real time, allowing personnel to obtain the world coordinates of the current point to be measured. Furthermore, the touchscreen can also display the three-dimensional coordinates, dimensions, and posture of target objects, such as nuclear equipment, in real time based on the control assembly's calculation and analysis results. It should be noted that to enhance the ease of use of the touchscreen, the touchscreen can also be installed on a handheld terminal.

[0091] In this embodiment, the control component can not only generate the three-dimensional coordinates, size, posture and other information of the target object based on the world coordinates of the measured point, but can also further automatically verify the measurement results and preset results based on the measurement purpose, and generate a verification report. If the verification results show that there is a deviation, the control component can also generate adjustment suggestions based on the deviation.

[0092] It should be noted that when intersection measurement utilizes camera RT forward intersection technology, in this embodiment, a laser ranging assembly is preferably also installed on the rotating assembly 2. When performing intersection measurement, the existing linear equations between actual and ideal image points can be used to solve them based on the least squares method to determine the three-dimensional coordinates of the points to be measured. The geometric significance of this least squares solution is that the sum of the squares of the distances from the intersection point of multiple photogrammetric assemblies 1 to the spatial ray family defined by the optical center and image points of each photogrammetric assemblies 1 is minimized. For the intersection of two photogrammetric assemblies 1, their spatial intersection point is the midpoint of the common perpendicular segment of these two spatial rays. In this case, the laser ranging assembly can be used to measure the distance to provide an accurate initial distance value. High-precision three-dimensional coordinates can then be obtained through bundle adjustment, further improving the accuracy of coordinate calculation.

[0093] Furthermore, the laser ranging component can also be used to illuminate the calibration point on one side of the point to be measured when the shooting center of the photogrammetry component 1 is aligned with the point to be measured, so as to use whether the laser ranging component accurately illuminates the calibration point to determine whether the shooting center of the photogrammetry component 1 is aligned with the point to be measured, thereby further ensuring the accuracy of photogrammetry.

[0094] Based on this, step S50 may be further included between step S5 and step S6: Step S50: If the laser emitted by the laser ranging component is aligned with the calibration point, proceed to step S6; if there is a deviation between the laser emitted by the laser ranging component and the calibration point, use the photogrammetry component 1 to capture images of the calibration point and the laser point irradiated around the calibration point, and calculate the coordinates of the calibration point and the laser point in the coordinate system of the photogrammetry component 1 based on the captured image. Then, based on the coordinates, calculate the deviation angle between the calibration point and the laser point, and control the rotation component 2 to rotate based on the deviation angle until the laser emitted by the laser ranging component is aligned with the calibration point, and then proceed to step S6.

[0095] Among them, the point to be measured can be a moving target, and the calibration point can be a cooperative target formed by the fusion of a prism target ball and a photogrammetric mark. Specifically, the moving target can be a structure that is approximately spherical with multiple planes, each plane serving as a measuring surface, with coding marks and circular measuring marks affixed to the measuring surface. The approximately spherical structure can ensure that the photogrammetric component 1 can observe the marks on the corresponding measuring surface at any angle; in addition, a measuring probe can be installed under the moving target, and the length of the measuring probe can be 1000mm. The probe on the measuring probe can be made of materials such as silicon nitride, zirconium oxide and ruby. The selection of materials can be selected according to actual needs. Among them, the moving target is a rigid structure. Based on this, there is a fixed spatial distance relationship between each mark on each measuring surface and the probe. The distance matrix between each mark on the measuring surface and the probe can be obtained by calculation.

[0096] In order to improve recognition efficiency and positioning accuracy, the above-mentioned signs can adopt retroreflective signs. Retroreflective signs are composed of glass beads, base glue, base material and back glue. Glass beads are used for reflection. The advantage of glass beads is that high-contrast images can be produced through low-intensity exposure. Its reflective efficiency is more than 100 to 1000 times that of ordinary white signs under the same lighting conditions.

[0097] The image of the retroreflective marker made of glass microbeads on the photogrammetry component 1 is clear and prominent, appearing as a group of circular or elliptical bright spots. The image size of the retroreflective marker directly affects the measurement accuracy. Since too few pixels of the retroreflective marker affect the extraction accuracy, too many pixels will cause eccentricity problems. Therefore, in this embodiment, it is preferred that the number of pixels occupied by the marker in the image is 7-15 pixels in the radial direction. Factors affecting the number of pixels occupied by the marker imaging include: the distance between the marker point and the camera, the lens focal length, the camera resolution, the pixel size, etc. The maximum measurement distance between the marker and the camera is set to 10m. The lens focal length is calculated to be 25mm based on the camera field of view, resolution and pixel size. Then, according to the pinhole imaging principle, it is obtained (4.5×10 3 ) / D=25 / (10×10 3), from which we calculate the spatial resolution D of the camera at a position of 10m to be 1.8mm. Taking the number of pixels occupied by the logo in the image as an example, we further calculate the logo's diameter to be 1.8 × 7 = 12.6mm.

[0098] To further improve the measurement accuracy of the photogrammetry component 1, the sign image can also be processed to extract the center of the circular sign image. Specifically, the circular sign is imaged as an ellipse after being imaged by the lens of the photogrammetry component 1. To achieve sub-pixel precision positioning of the ellipse center, an edge detection operator is first used to coarsely locate the ellipse edge with integer pixel precision. Then, sub-pixel edge tracking is performed on the pixel-level edge points to obtain sub-pixel edge points. Then, an ellipse least squares fitting is performed on the extracted sign edge points to determine the sign center ellipse. Finally, a grayscale weighted centroid algorithm is used to accurately determine the sign center.

[0099] Among them, the operation steps of the edge detection operator are as follows: the first step is to use a Gaussian filter to filter the image to be processed to eliminate image noise; the second step is to use the finite difference method of the first-order partial derivative to calculate the amplitude and direction of the image gradient; the third step is to suppress the maximum value of the image gradient subvalue calculated in the second step; the fourth step is to use the double threshold algorithm to detect the image edge and connect the detected edges.

[0100] The steps of edge tracking are as follows: First, get the starting pixel for searching the boundary of a certain area, use the first pixel P0 of a new area obtained by the search as the starting pixel for searching the boundary of the area, and define a variable dir to store the moving direction. The neighborhood of each pixel has eight directions; Second, search the 3*3 neighborhood of the current pixel in a counterclockwise direction. The starting search direction is selected according to the following principle: if dir is an odd number, divide (dir+6) by 8, and the direction shown by the remainder is used as the starting search direction. If dir is an even number, use ( +7) divided by 8, the direction indicated by the remainder is used as the starting search direction, and the variable is updated when the first pixel with the same value as the current pixel is found in the 3*3 neighborhood of the current pixel. The value of the pixel being searched is also a new boundary point P n ; The third step, when the edge pixel P at the current position n is equal to the second edge pixel P1, and the previous edge pixel P n-1 If it is equal to P0, stop searching and complete the edge tracking this time, otherwise repeat the second step.

[0101] The steps to determine the center ellipse of the mark are as follows: First, the black holes and "bright spot" edges obtained after edge detection operator and edge tracking are tested for perimeter, aspect ratio, area and circularity (shape factor); second, the image is tested for pixel grayscale.

[0102] Among them, the grayscale weighted centroid algorithm is an existing technology, so the specific calculation process of using the grayscale weighted centroid algorithm to determine the center of the mark will not be repeated here.

[0103] After determining the landmark center of the landmark point, it is also necessary to identify the landmark point with coded information (the coded information is made according to pre-set rules) and complete the matching of single-point homonymous points. Finally, a rear intersection calculation is performed based on the information of each photo to determine the position of each photo and complete the relative orientation of multiple photos.

[0104] The essence of landmark point recognition is the point pattern matching problem based on feature points in computer vision in the photogrammetry component 1, which involves issues such as perspective projection principle, affine transformation, perspective projection transformation and projection transformation invariant.

[0105] The analysis and calculation process of perspective projection principles are as follows: The imaging process is the projection of three-dimensional space onto a two-dimensional plane. This involves projecting certain properties of a spatial object onto a plane according to a certain pattern, forming an image. This process is commonly referred to as perspective projection. When the projection lines intersect at a point, it is called central perspective projection; when the projection lines are parallel, it is called parallel perspective. The image formed by an actual camera can be simulated using a central perspective model. This model states that a point in three-dimensional space is projected onto the image plane to produce a corresponding image point. All projection lines, as well as the extension of the line connecting the point to be measured and its image point, intersect at a single point, which is the projection center. Figure 2 The central perspective projection diagram of the photogrammetry component 1 during imaging provided in this embodiment is as follows: Figure 2 As shown, select a three-dimensional coordinate system XYZ, set the coordinate origin O at the projection center (also called the perspective center), the optical axis is the Z axis, the image plane is Z=ƒ (ƒ is the focal length), the origin o of the image plane coordinate system xy is the intersection of the image plane and the Z axis, and the X axis and Y axis are parallel to the x axis and y axis respectively. Then the coordinates of the point (X, Y, Z) in three-dimensional space and its image point (x, y) have the following nonlinear perspective transformation relationship:

[0106] Different camera viewpoints relative to the same target in three-dimensional space will cause changes in the target's orientation and posture relative to the camera. This alters the target's image in the camera, resulting in different images of the same target. When the object is planar and the camera's optical axis is parallel to the normal of the object's plane, relative motion between the camera and the object causes rotation and translation of the object's image. Changes in the distance between the camera and the object, in turn, cause changes in the size of the object's image. In practical applications, it is difficult to maintain a constant relative distance and orientation between the object being measured and the camera. Recognizing point-coded markers requires matching the extracted point set with the template points, thereby restoring the coordinate system of the marker's design. The photographic imaging of the marker will produce affine transformations or perspective projection transformations in the image, such as rotation, translation, scaling, and distortion, which raises the issues of affine and perspective projection transformations in computer vision.

[0107] The analysis and calculation process of affine transformation is as follows: In Euclidean space, if a mapping can turn three collinear points into three collinear points, it is called an affine transformation. Affine transformation consists of six parameters. If an affine transformation turns one figure into another in a plane, the two figures are said to be affine equivalent. It can be proved that: 1. Any two triangles on the same plane are affine equivalent; 2. Any two tetrahedrons in the same space are affine equivalent. Based on this, the affine transformation is written in matrix form as:

[0108] in, They represent the six parameters of the transformation matrix, which can transform the coordinates (x, y) of a point into (u, v).

[0109] The analysis and calculation process for perspective projection transformation is as follows: The characteristic of the perspective projection imaging model is that all light from the scene passes through a projection center, which corresponds to the center of the lens. Perspective projection transformation has two more parameters than affine transformation, with a total of eight parameters. Perspective projection transformation is written in matrix form as:

[0110] in, Represents the eight parameters of the transformation matrix, which can transform the coordinates (x, y) of a point into (u, v).

[0111] For the projection transformation invariant (i.e., the cross ratio), the analysis process is as follows: the cross ratio is an invariant in the projection transformation. The one-dimensional cross ratio is defined based on the distance between four points on the same straight line. Figure 3 The cross ratio definition diagram in the perspective projection transformation of the photogrammetry component 1 provided in this embodiment is composed of Figure 3It can be seen that the intersection ratio of four points (A, B, C, D) on the same straight line L is defined as:

[0112] Similarly, the four points on the same straight line L' The cross ratio is defined as:

[0113] The four projection lines OA, OB, OC, and OD passing through the focus O are defined as:

[0114] Where: are the angles between two adjacent projection lines between the projection lines OA, OB, OC, and OD, respectively. Figure 3 shown.

[0115] From formula (27), formula (28) and formula (29), we can get:

[0116] Under projective transformations, the area of a planar object and the angle between two intersecting lines change, but in projective geometry, the two-dimensional intersection ratio of five coplanar points is an invariant. Therefore, under projective transformations, the invariant two-dimensional intersection ratio can be used to describe the shape of an object.

[0117] When the distance between a planar object and the camera is relatively small, the projection lines are approximately parallel, and affine transformations can be used to approximate central perspective. For the same scene (whether 2D or 3D), the geometric shapes of images captured by cameras at different locations and angles vary. Despite these different geometric shapes, the geometric deformation between any two images can be described by a projective transformation. When the distance between the camera and the scene is much larger than the size of the scene, the projective transformation can be approximated by an affine transformation.

[0118] Point-coded mark recognition can be viewed as a point-matching problem between two images. The recognition method involves using a designed template point to find the image point of the template point in the image. Then, using an affine transformation, the image points are restored to the designed coordinates, while simultaneously determining the affine transformation parameters. The affine transformation parameters are used to restore the image points of the coded points surrounding the template point. These are then compared with the designed coordinates and decoded to obtain the code of the coded mark.

[0119] When matching points with the same name as a single point marker, the epipolar matching algorithm in photogrammetry can be used. Specifically, according to epipolar geometry, if the image point of a certain object point on one image is known, then the corresponding image point of this image point on other images must be on its corresponding epipolar line. If the exact value or approximate value of the orientation parameter is known, the corresponding epipolar line can be calculated. The calculation process is as follows: Taking three photogrammetry components 1 (i.e., three base stations) as an example, It is the optical center of each base station lens. For each image plane, is the principal point of each image, is the corresponding image point of the object point P, Image point exist The corresponding epipolar line on the image. Suppose the coordinates of a point in the image space coordinate system of base station No. 1 are , its coordinates in the image space coordinate system of the second base station are , then the following formula holds:

[0120] Where: M1 and M2 are the rotation matrices of base station 1 and base station 2 relative to the object space coordinate system, is the translation parameter of base station 1 and base station 2 in the object space coordinate system .

[0121] And because in the space coordinate system of base station No. 1, The coordinates of are known values, respectively and , so according to formula (31) we can get The coordinates in the No. 2 base station image space coordinate system are 、 .

[0122] because The three points are coplanar, so in the No. 2 base station image space coordinate system, the plane equation can be expressed as:

[0123] In the image space coordinate system of the second base station, the plane equation of the image plane I2 is:

[0124] Substituting formula (33) into formula (32), we can get the image point Epipolar line I on image plane I2 12 The equation is:

[0125] Substituting the determinant constants in formula (34) with A, B, and C respectively, formula (34) can be simplified as follows:

[0126] Similarly, we can also get the image point Epipolar line I on image plane I3 13 The specific calculation process will not be described here.

[0127] After identifying the marker points with coded information and completing single-point matching of the same-name points according to the above method, the recognition accuracy of the marker points can be effectively guaranteed, thereby effectively improving the calculation accuracy during the rear intersection calculation based on the photo information.

[0128] It should be noted that the measurement method provided in this embodiment is based on the spatial positioning measurement of the measured point by multiple base stations, which belongs to multi-eye stereo vision measurement. Its data processing basis is the collinearity condition equation. The data processing mode can be specifically divided into two modes: one is the step-by-step mode of first orientation and then coordinate measurement; the other is the overall solution mode in which orientation and coordinate measurement are performed simultaneously. The step-by-step measurement mode is a calculation process of single-image space rear intersection and multi-base station space front intersection based on the collinearity equation. The overall solution mode is a process of treating the image coordinates of the control point, the image coordinates of the point to be determined, and other data (such as relative control) as observation values, and solving the external orientation elements of the image and the spatial coordinates of the point to be determined as a whole. It is also the ray bundle adjustment solution in photogrammetry, referred to as the bundle adjustment. When calculating the spatial coordinates of the point to be measured, one of the above two data processing modes can be selected for execution. Since the above two data processing modes are both existing technologies, their specific calculation processes will not be repeated here.

[0129] In this embodiment, the control assembly can be composed of components such as a power module, a GNSS module, a remote control module, a display module, a logic control module, a signal output module, and an external chassis. The logic control module is an integrated circuit (PCB) board equipped with an FPGA chip, a level conversion chip, a signal conversion chip, a superheterodyne RF signal receiving chip, a power supply chip, and related peripheral designs. It is the core board for processing digital signals. Therefore, the control assembly provided in this embodiment utilizes a highly mature and reliable FPGA chip to construct the entire system. The control assembly also supports wireless connectivity, superheterodyne RF control, and direct control via a host computer.

[0130] In summary, the measurement method provided in this embodiment utilizes multi-base station joint calibration technology to accurately calibrate the transformation relationship between each photogrammetric component 1 and the base station coordinate system, ensuring consistent measurement accuracy across different photogrammetric components 1. Furthermore, when measuring a target point, a multi-front intersection method is employed to accurately calculate the spatial coordinates of the target point. Furthermore, this measurement method enables automatic tracking measurement of multiple target points (which can be achieved by deploying multiple targets or by gradually moving a mobile target). This measurement method significantly enhances the automation of the measurement process, enabling efficient and high-precision measurement in complex environments.

[0131] This embodiment also provides a measurement system, which applies the above-mentioned measurement method and includes a control component, a plurality of photogrammetric components 1 and a plurality of rotation components 2; the plurality of photogrammetric components 1 are mounted on the plurality of rotation components 2 in a one-to-one correspondence, and the plurality of photogrammetric components 1 and the plurality of rotation components 2 are connected to the control component; the photogrammetric component 1 is used to photograph the reference point and the point to be measured within its photographing range when its photographing center is aligned with the reference point, and obtain the coordinates of the reference point and the point to be measured in the coordinate system of the photogrammetric component 1; the control component is preset with a conversion relationship between the base station coordinate system and the world coordinate system, and the control component is used to The coordinate information obtained by multiple photogrammetric components 1 is received, and intersection measurement is performed based on the conversion relationship between the selected base station coordinate system and the coordinate system of each photogrammetric component 1 to calculate the coordinate information of the reference point and the point to be measured in the base station coordinate system, and then the coordinate information of the reference point and the point to be measured in the world coordinate system is calculated; the control component is also used to calculate the relative angle between the reference point and the point to be measured based on the coordinate information of the reference point and the point to be measured in the world coordinate system, and control the multiple rotating components 2 to drive the photogrammetric components 1 thereon to rotate according to the relative angle, so that the shooting center of each photogrammetric component 1 is aligned with the point to be measured.

[0132] The measurement system provided in this embodiment applies the above-mentioned measurement method, and thus the measurement system and the above-mentioned measurement method can solve the same technical problems and achieve the same technical effects, which will not be described in detail here.

[0133] Among them, the control component includes an error compensation parameter module, in which the error compensation parameters are preset. The control component is used to calculate the coordinates of the reference point and the point to be measured in the world coordinate system based on the error compensation parameters, the coordinate information of the reference point and the point to be measured in the base station coordinate system, and the conversion relationship between the base station coordinate system and the world coordinate system.

[0134] When using the measurement system to perform coordinate measurement, the measurement system can be started first to ensure that the system can operate normally, and then preliminary calibration of each photogrammetric component 1 can be performed to determine its own coordinate system and the base station coordinate system. The relative position relationship between the photogrammetric component 1 and the rotation component 2 is then calibrated. Multiple photogrammetric components 1 are then used to automatically capture multiple images of the target area, collecting the spatial coordinates of the image markers on the target at the reference point and the point to be measured in the base station coordinate system. The error compensation parameter module and multi-source data fusion processing module in the control component are then used to perform error compensation, forward intersection measurement calculations, and adjustment calculations on the various data measured by each module in the system, and output the accurate three-dimensional coordinates of the point to be measured. Among them, the camera intrinsic parameters and camera extrinsic parameters can be taken into account in the measurement process during the photogrammetric measurement performed by the photogrammetric component 1 using the control system equipped by the photogrammetric component 1 itself.

[0135] like Figure 4 As shown, the rotating assembly 2 includes an upper turntable 20 and a lower turntable 21, and both the upper turntable 20 and the lower turntable 21 include a rotating output end; the central axis of the rotating output end of the upper turntable 20 is a horizontal axis, and the photogrammetric assembly 1 is mounted on the rotating output end of the upper turntable 20, and the upper turntable 20 is used to drive the photogrammetric assembly 1 to rotate around the central axis of its rotating output end; the central axis of the rotating output end of the lower turntable 21 is a vertical axis, and the upper turntable 20 is mounted on the rotating output end of the lower turntable 21, and the lower turntable 21 is used to drive the upper turntable 20 and the photogrammetric assembly 1 to rotate around the central axis of their rotating output ends.

[0136] The rotation of both the upper turntable 20 and the lower turntable 21 can be achieved through motors and other rotary drive components. Specifically, the upper turntable 20 can control the rotation of the photogrammetric assembly 1 mounted thereon according to commands from the control component, achieving high-precision position rotation of the photogrammetric assembly 1 in the pitch direction while simultaneously outputting real-time pitch angle information. The lower turntable 21 can control the rotation of both the upper turntable 20 and the photogrammetric assembly 1 mounted thereon according to commands from the control component, achieving high-precision position rotation of the photogrammetric assembly 1 in the horizontal direction while simultaneously outputting real-time horizontal angle information.

[0137] As can be seen, the upper turntable 20 serves as the base for the horizontal axis of the rotating assembly 2, while the lower turntable 21 serves as the base for the vertical axis of the rotating assembly 2. To ensure the capture range of the photogrammetry assembly 1, in this embodiment, the rotating assembly 2 preferably has a horizontal measurement range of 0° to 360° and a pitch measurement range of -120° to 120°. Furthermore, the horizontal and vertical angle measurement accuracies of the rotating assembly 2 are both no greater than 4".

[0138] Furthermore, the lower turntable 21 can be fixed on a tripod, and the rotating assembly 2 can be accurately installed at the control point through the optical centering device on the tripod. In addition, a leveling structure can be provided on the rotating assembly 2. Specifically, the rotating assembly 2 can be roughly leveled by a circular leveling bubble and finely leveled by a strip leveling bubble, so that the photogrammetric assembly 1 is parallel to the ground level. When the rotating assembly 2 drives the photogrammetric assembly 1 to rotate, the rotation angle change is measured in real time by the angle measurement module on the rotating assembly 2.

[0139] The upper turntable 20 can be composed of an inner frame rotation unit, an inner frame angle measurement unit, and a power management module. The inner frame rotation unit includes an angular contact bearing and mounting structure, a torque motor, and a motor driver. The inner frame angle measurement unit includes a programmable board, a readhead, a circular grating, and other components. The inner frame power management module provides power to the upper turntable 20's electrical components and also to the photogrammetry assembly 1. The programmable board controls the motor driver based on control commands from the control assembly and also synchronizes the position and pose of the inner frame rotation unit with trigger signals to the control assembly.

[0140] The lower turntable 21 can be composed of an outer frame rotation unit, an outer frame angle measurement unit and a PCB conductive slip ring, wherein the outer frame rotation unit includes an angular contact bearing, a torque motor, and a motor driver; the outer frame angle measurement unit includes a reading head and a circular grating; and the PCB conductive slip ring is used to transmit digital signals and power supply.

[0141] In order to ensure the assembly accuracy, the lower turntable 21 needs to be assembled according to the following assembly process requirements: before installing the angular contact bearing, loosen the bearing's own connecting screws, install the bearing outer ring screws using the cross method, and after installing the angular contact bearing, use a dial indicator and micrometer to measure the bearing diameter runout and shaft sleeve, and the diameter runout and shaft sleeve are required to reach 2u; the bearing inner ring and the upper turntable 20 are over-fitted. After the vertical axis chamfer of the upper turntable 20 is installed into the bearing inner ring, it is fixed with screws and installed using the cross method. After installation, the dial indicator and micrometer are used to measure the diameter runout and shaft sleeve of the upper turntable 20, and the requirement is to reach 2u; after the circular grating and grating reading head of the lower turntable 21 are installed, the circular grating outer ring runout is required to be within 0.01, and the grating runout accuracy is adjusted by adjusting the grating mounting screws, and the distance between the reading head and the grating is ensured to be 0.8±0.15mm.

[0142] To ensure the rotation accuracy of the rotating assembly 2 , the mechanical design accuracy of the rotating assembly 2 may be controlled in advance. The mechanical design accuracy of the rotating assembly 2 includes the accuracy of the upper turntable 20 , the accuracy of the lower turntable 21 , and the rotational angular acceleration.

[0143] Among them, the accuracy of the upper turntable 20 is manifested in the eccentricity of the shaft system and the inclination of the shaft system. For its eccentricity and inclination of the shaft system, the accuracy of the design axis of the angular contact ball bearing of the upper turntable 20 needs to be controlled within a cylindricity of 1um and a verticality of 1um, and the angular contact ball bearing is installed in an interference fit manner, while ensuring that its radial runout is maximum 1um; in addition, considering the eccentricity error and tilt error, the entire runout value of the upper turntable 20 is controlled within 8u, and the runout of the grating end is within ±5um, thereby ensuring that the structural mechanical design accuracy is 27.47 arc seconds.

[0144] The accuracy of the lower turntable 21 is also reflected in the amount of shaft eccentricity and shaft tilt. For both eccentricity and shaft tilt, the design axis of the angular contact ball bearing of the lower turntable 21 must be controlled to a precision of 2μm in cylindricity and 2μm in perpendicularity. An interference fit is used to ensure a maximum radial runout of 2μm. Taking into account the eccentricity and tilt errors, the overall runout of the lower turntable 21 is controlled within 8μm, and the runout at the grating end is within ±5μm, thus ensuring a structural mechanical design accuracy of 20.6 arc seconds. Furthermore, based on the inherent rigidity of the lower turntable 21 and the load-induced deformation of the bearing, the lower turntable 21 is preferably constructed of a rigid material, with deformation caused by load torque limited to less than 1μm.

[0145] The rotational angular acceleration needs to take into account the rotational angular acceleration of the upper turntable 20 and the rotational angular acceleration of the lower turntable 21. In this embodiment, the motor torque of the upper turntable 20 is preferably 1.2N*m, and the rotational friction torque of the upper turntable 20 is 0.5N*m. Substituting them into the rotational angular acceleration calculation formula, the rotational angular acceleration of the upper turntable 20 is: ε=T / J=(1.2-0.5) / 0.007=100rad / s 2 , where 1 rad = 57.3°. In this embodiment, the motor torque of the lower turntable 21 is preferably 1.2 N*m, the rotational friction torque of the upper turntable 20 is 0.5 N*m, and the rotational friction torque of the slip ring is 0.1 N*m. Substituting these into the rotational angular acceleration calculation formula, the rotational angular acceleration of the lower turntable 21 is: ε = T / J = (2.46 - 1.4 - 0.1) / 0.07 = 13.5 rad / s 2 , where 1rad=57.3°.

[0146] In summary, the measurement system provided in this embodiment can effectively improve the measurement accuracy of the measurement system by controlling the mechanical design accuracy of the rotating assembly 2 .

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A measurement method, characterized in that: include: S1: arranging a reference point and a plurality of points to be measured in a control field, installing a plurality of photogrammetric components (1) on a plurality of rotating components (2) in a one-to-one correspondence, aligning the shooting centers of the plurality of photogrammetric components (1) with the reference point, and ensuring that at least one point to be measured is located within the shooting range of the plurality of photogrammetric components (1); S2: Selecting the coordinate system of one of the photogrammetric components (1) as the base station coordinate system, using multiple photogrammetric components (1) to photograph the reference point and obtain coordinate information, and calibrating the conversion relationship between the coordinate system of each photogrammetric component (1) and the base station coordinate system based on the measurement results; S3: using multiple photogrammetric components (1) to photograph the points to be measured within their photographing range and obtain coordinate information, using a control component to receive the coordinate information obtained by each photogrammetric component (1), and performing intersection measurement based on the conversion relationship between the coordinate system of each photogrammetric component (1) and the base station coordinate system, so as to calculate the coordinate information of the reference point and the point to be measured in the base station coordinate system; S4: Based on the coordinate information of the reference point and the point to be measured in the base station coordinate system and the conversion relationship between the base station coordinate system and the world coordinate system preset in the control component, the control component is used to calculate the coordinates of the reference point and the point to be measured in the world coordinate system; S5: Calculating the relative angle between the reference point and the point to be measured based on the coordinates of the reference point and the point to be measured, and causing the control component to control the plurality of rotating components (2) to respectively drive the photogrammetric components (1) thereon to rotate based on the relative angle, until the shooting centers of the plurality of photogrammetric components (1) are aligned with the point to be measured, and the next point to be measured is located within the shooting range of the plurality of photogrammetric components (1); S6: using the point to be measured aligned with the shooting center of the plurality of photogrammetry components (1) as a new reference point; S7: Repeat steps S3-S6 until the coordinates of all the points to be measured in the world coordinate system are calculated.

2. The measuring method according to claim 1, wherein Intrinsic camera parameters and extrinsic camera parameters are preset in the photogrammetry component (1), so that the photogrammetry component (1) obtains coordinate information based on the intrinsic camera parameters, extrinsic camera parameters and the image captured by the component (1).

3. The measuring method according to claim 2, characterized in that The camera internal parameters include lens radial distortion parameters, lens decentering distortion parameters, image plane distortion parameters and internal orientation element error parameters, and the camera external parameters include position parameters and posture parameters of the photogrammetry component (1) in the world coordinate system.

4. The measuring method according to any one of claims 1 to 3, characterized in that: In step S4, error compensation parameters are preset in the control component, and based on the error compensation parameters, the coordinate information of the reference point and the point to be measured in the base station coordinate system, and the conversion relationship between the base station coordinate system and the world coordinate system, the coordinates of the reference point and the point to be measured in the world coordinate system are calculated.

5. The measuring method according to claim 4, characterized in that The rotating assembly (2) is a theodolite, and the error compensation parameters include a vertical axis tilt error of the rotating assembly (2), an eccentric amplitude of an aiming portion of the rotating assembly (2), and an eccentric phase of the aiming portion of the rotating assembly (2).

6. The measuring method according to claim 4, characterized in that The error compensation parameters are calculated by actually measuring a plurality of known measurement points with known angle values and combining the following two formulas: Where, is the eccentricity amplitude of the aiming part of the rotating assembly (2), is the eccentric phase of the aiming portion of the rotating assembly (2), is the vertical axis tilt error of the rotating assembly (2); is the vertical angle value of the known measuring point, is the horizontal angle value of the known measuring point; is the vertical angle value obtained when actually measuring a known measuring point. It is the horizontal angle value obtained when actually measuring a known measuring point; is the radius of the horizontal grating in the rotating assembly (2); is the conversion constant for converting radians into the angle unit "arc seconds", =206264.806".

7. The measuring method according to any one of claims 1 to 3, characterized in that: The rotating component (2) is provided with an angle measurement module, which is connected to the control component. The angle measurement module is used to detect the rotation angle of the rotating component (2) during the rotation of the rotating component (2) and send the detected rotation angle information to the control component; the control component is used to compare the received rotation angle with the calculated relative angle and control the rotating component (2) to stop rotating when the rotation angle is equal to the relative angle.

8. A measurement system, applying the measurement method according to any one of claims 1 to 7, characterized in that: It includes a control component, a plurality of photogrammetry components (1), and a plurality of rotation components (2); The plurality of photogrammetric components (1) are mounted on the plurality of rotating components (2) in a one-to-one correspondence, and the plurality of photogrammetric components (1) and the plurality of rotating components (2) are all connected to the control component; the photogrammetric component (1) is used to photograph the reference point and the points to be measured within its photographing range when its photographing center is aligned with the reference point, and obtain the coordinates of the reference point and the points to be measured in the coordinate system of the photogrammetric component (1); The control component is preset with a conversion relationship between the base station coordinate system and the world coordinate system, and the control component is used to receive coordinate information obtained by multiple photogrammetric components (1), and perform intersection measurement based on the conversion relationship between the selected base station coordinate system and the coordinate system of each photogrammetric component (1), so as to calculate the coordinate information of the reference point and the point to be measured in the base station coordinate system, and then calculate the coordinate information of the reference point and the point to be measured in the world coordinate system; The control component is further used to calculate the relative angle between the reference point and the point to be measured based on the coordinate information of the reference point and the point to be measured in the world coordinate system, and to control the plurality of rotating components (2) to respectively drive the photogrammetric components (1) thereon to rotate based on the relative angle, so that the shooting center of each photogrammetric component (1) is aligned with the point to be measured.

9. The measurement system according to claim 8, characterized in that The control component includes an error compensation parameter module, in which error compensation parameters are preset. The control component is used to calculate the coordinates of the reference point and the point to be measured in the world coordinate system based on the error compensation parameters, the coordinate information of the reference point and the point to be measured in the base station coordinate system, and the conversion relationship between the base station coordinate system and the world coordinate system.

10. The measurement system according to claim 8, characterized in that The rotating assembly (2) comprises an upper turntable (20) and a lower turntable (21), and both the upper turntable (20) and the lower turntable (21) comprise a rotating output end; The central axis of the rotation output end of the upper turntable (20) is a horizontal axis, the photogrammetric component (1) is mounted on the rotation output end of the upper turntable (20), and the upper turntable (20) is used to drive the photogrammetric component (1) to rotate around the central axis of its rotation output end; The central axis of the rotation output end of the lower turntable (21) is a vertical axis, the upper turntable (20) is mounted on the rotation output end of the lower turntable (21), and the lower turntable (21) is used to drive the upper turntable (20) and the photogrammetry assembly (1) to rotate around the central axis of the rotation output end thereof.

Images