Measurement method and measurement system

Abstract

The application provides a kind of measurement method and measurement system, it is related to measurement technical field.The measurement method makes the photographing center of multiple photogrammetric components in step S1 with reference point alignment;In step S2, the conversion relationship between photogrammetric component coordinate system and base station coordinate system is calibrated;In step S3, the intersection measurement of to-be-measured point is carried out, and the coordinates of reference point and to-be-measured point under base station coordinate system are calculated;In step S4, the coordinates of reference point and to-be-measured point under world coordinate system are calculated;In step S5, the rotation of photogrammetric component is driven by rotating component using control component, until the photographing center of multiple photogrammetric components is aligned with to-be-measured point;In step S6, new reference point is determined;In step S7, steps S3-S6 are repeated, so as to calculate the coordinates of all to-be-measured points under world coordinate system, not only can the automatic tracking measurement of multiple to-be-measured points be realized, and the rotation of photogrammetric component can be controlled, and its shooting range is expanded.

Description

Technical Field

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

[0002] In the development of precision measurement and positioning technologies, dual-base station spatial positioning systems have become an important technical means, widely used in various high-precision measurement tasks. Dual-base station spatial positioning systems typically use two cameras as dual base stations to measure the spatial coordinates of a target object, such as pre-determined key points on objects like nuclear power equipment, nuclear power pipelines, and nuclear power construction tracks.

[0003] In existing dual-base station spatial positioning systems, the dual cameras are fixed, meaning that the two cameras are fixed at both ends of the same crossbar. During measurement, it is necessary to first set up reference points with known coordinates in the control field and determine the position of each target object in the control field based on the field of view of the dual cameras. Then, the dual cameras first perform intersection measurements with the reference points to calibrate the camera positions, and then use the dual cameras to perform intersection measurements with each target object to measure the position of each target object relative to the reference points, thereby determining the coordinates of each target object.

[0004] However, during the construction of nuclear engineering projects, the construction environment in the control field is complex, and targets are easily obscured. In such cases, it is necessary to move the dual cameras to bring the targets into the camera's field of view. However, once the cameras are moved, their positions must be recalibrated, resulting in a complex measurement process and low measurement efficiency. Furthermore, the shooting range of fixed dual cameras is limited, often only supporting the measurement of targets within the same control field. If the control field range increases, additional base stations and reference points must be added, resulting in a large workload. Summary of the Invention

[0005] The purpose of this invention is to provide a measurement method and system to alleviate the technical problems existing in the dual-base station spatial positioning system. The fixed position of the dual cameras in the existing dual-base station spatial positioning system is fixed. When the target object is blocked, the position of the dual cameras needs to be moved, and then the position of the dual cameras needs to be recalibrated, which leads to 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 need to be added, which increases the workload.

[0006] In a first aspect, the present invention provides a measurement method, comprising: S1: Arrange reference points and multiple test points in the control field, install multiple photogrammetry components one by one on multiple rotating components, align the shooting centers of multiple photogrammetry components with the reference points, and ensure that at least one test point is within the shooting range of multiple photogrammetry components. S2: Select the coordinate system of one of the photogrammetric components as the base station coordinate system, use multiple photogrammetric components to take pictures of the reference point and obtain coordinate information, and calibrate the transformation relationship between the coordinate system of each photogrammetric component and the base station coordinate system based on the measurement results; S3: Multiple photogrammetric components are used to photograph the points to be measured within their shooting range and obtain coordinate information. The control component receives the coordinate information obtained by each photogrammetric component and performs intersection measurement based on the transformation 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 points 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 transformation 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 using the control component. S5: Calculate 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 make the control component control multiple rotating components to drive the photogrammetry components on them to rotate based on the relative angle until the shooting center of the multiple photogrammetry components is aligned with the point to be measured, and make the next point to be measured within the shooting range of the multiple photogrammetry components. S6: Use the point to be measured, aligned with the shooting center of multiple photogrammetry components, as the new reference point; S7: Repeat steps S3-S6 until the coordinates of all points to be measured in the world coordinate system are calculated.

[0007] In an optional implementation, 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 it captures.

[0008] In an optional implementation, the camera intrinsic parameters include lens radial distortion parameters, lens eccentricity distortion parameters, image plane distortion parameters, and interior orientation element error parameters, while the camera extrinsic parameters include the position and attitude parameters of the photogrammetric component in the world coordinate system.

[0009] In an optional implementation, in step S4, an error compensation parameter is preset in the control component, and based on the error compensation parameter, the coordinate information of the reference point and the point to be measured in the base station coordinate system, and the transformation 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 the vertical axis tilt error of the rotating component, the eccentricity amplitude of the aiming part of the rotating component, and the eccentricity phase of the aiming part of the rotating component.

[0011] In an optional implementation, the error compensation parameter is calculated by actually measuring multiple known angle values ​​at known measurement points and combining the following two formulas:

[0012] In the formula, The eccentricity amplitude of the aiming part of the rotating assembly. For the eccentric phase of the aiming part of the rotating assembly, The vertical axis tilt error of the rotating component; Given the vertical angle value of the measurement point, The horizontal angle value of the known measurement point; The vertical angle value is the value measured when a known measurement point is actually measured. This refers to the horizontal angle value measured during actual measurement of a known measurement point; The radius of the horizontal grating in the rotating assembly; The conversion constant for converting radians to the angle unit "arcsecond". =206264.806".

[0013] In an optional embodiment, the rotating component 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 during its rotation 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 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 that applies the measurement method described in any of the foregoing embodiments, including a control component, a plurality of photogrammetric components and a plurality of rotating components; Multiple photogrammetry components are mounted one-to-one on multiple rotating components, and both the multiple photogrammetry components and the multiple rotating components are connected to the control component; the photogrammetry component is used to photograph the reference point and the point to be measured within its shooting range when its shooting center is aligned with the reference point, and to obtain the coordinates of the reference point and the point to be measured in the coordinate system of the photogrammetry component; The control component is preset with a transformation relationship between the base station coordinate system and the world coordinate system. The control component is used to receive coordinate information obtained by multiple photogrammetry components, and to perform intersection measurement based on the transformation relationship between the selected base station coordinate system and the coordinate system of each photogrammetry component, 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 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 to control the multiple rotating components to drive the photogrammetry components on them to rotate according to the relative angle, so that the shooting center of each photogrammetry component is aligned with the point to be measured.

[0015] In an optional implementation, the control component includes an error compensation parameter module. The error compensation parameter includes a preset error compensation parameter. 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 parameter, the coordinate information of the reference point and the point to be measured in the base station coordinate system, and the transformation 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, both of which include a rotation output end; The central axis of the rotating output end of the upper turntable is a horizontal axis. The photogrammetry component is installed on the rotating output end of the upper turntable. The upper turntable is used to drive the photogrammetry component to rotate around the central axis of its rotating output end. The central axis of the rotation output end of the lower turntable is a vertical axis. The upper turntable is mounted on the rotation output end of the lower turntable. The lower turntable is used to drive the upper turntable and the photogrammetry component to rotate around the central axis of its rotation output end.

[0017] The measurement method provided by this invention includes: S1: arranging a reference point and multiple test points in a control field, mounting multiple photogrammetry components one-to-one on multiple rotating components, aligning the shooting centers of the multiple photogrammetry components with the reference point, and ensuring that at least one test point is within the shooting range of the multiple photogrammetry components; S2: selecting the coordinate system of one of the photogrammetry components as the base station coordinate system, using the multiple photogrammetry components to photograph the reference point and obtain coordinate information, and calibrating the transformation relationship between the coordinate system of each photogrammetry component and the base station coordinate system based on the measurement results; S3: using the multiple photogrammetry components to photograph the test points within their shooting range and obtain coordinate information, using a control component to receive the coordinate information obtained by each photogrammetry component, and performing intersection measurement based on the transformation relationship between the coordinate system of each photogrammetry component and the base station coordinate system. S3: Calculate the coordinates of the reference point and the point to be measured in the base station coordinate system; S4: Based on the coordinates of the reference point and the point to be measured in the base station coordinate system, and based on the transformation relationship between the base station coordinate system and the world coordinate system preset in the control component, calculate the coordinates of the reference point and the point to be measured in the world coordinate system using the control component; 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 make the control component control multiple rotating components to drive the photogrammetry components on them to rotate according to the relative angle, until the shooting center of the multiple photogrammetry components is aligned with the point to be measured, and the next point to be measured is within the shooting range of the multiple photogrammetry components; S6: Take the point to be measured aligned with the shooting center of the multiple photogrammetry components as the new reference point; S7: Repeat steps S3-S6 until the coordinates of all points to be measured in the world coordinate system are calculated. The measurement method provided by this invention can be used to measure the three-dimensional spatial dimensions of nuclear equipment such as reactor shells during nuclear engineering construction, as well as for attitude measurement and correction of nuclear equipment, or for measurement operations in tasks such as welding deformation detection of main pipelines in nuclear power plants and installation and adjustment of high-precision tracks in nuclear power plants. When measuring target objects such as the aforementioned nuclear equipment, main pipelines, and high-precision tracks, a control field can first be established in the space surrounding the target object, and then step S1 of the measurement method in this invention can be performed within the control field. Specifically, in step S1, reference points with known coordinates can be arranged within the control field, and multiple key points can be determined on the target object based on its shape and attitude as multiple measurement points. Then, multiple rotating components and their photogrammetry components can be arranged at intervals within the control field. Each photogrammetry component can serve as a base station. Correspondingly, the measurement method provided by this invention is based on spatial positioning measurement of the target object using multiple base stations.The photogrammetry component can be a digital close-range photogrammetry component including a camera. In this case, the photogrammetry component has image recognition and processing functions and can obtain the coordinates of the reference point or the point to be measured in its coordinate system based on the captured images. The rotation component can be a theodolite including a motor, a horizontal turntable, and a vertical rotating shaft. During the arrangement of the rotation component and the photogrammetry component in step S1, the shooting center of each photogrammetry component must be aligned with the reference point. That is, the shooting center of each photogrammetry component must be on the same straight line as the reference point, and the reference point must be within the shooting range of multiple photogrammetry components. At the same time, at least one point to be measured must be located around the reference point to ensure that at least one point to be measured is within the shooting range of multiple photogrammetry components. Next, 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. Simultaneously, multiple photogrammetric components are used to photograph the reference point and obtain its coordinate information. Since the coordinates of the reference point are known, the transformation relationship between the coordinate system of each photogrammetric component and the base station coordinate system can be determined based on the coordinate information of the reference point obtained by each photogrammetric component. It should be noted that in step S2, the transformation relationship between the coordinate system of each photogrammetric component and the base station coordinate system can be determined 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 point to be measured within their shooting range and obtain its coordinate information. The control component can then receive the coordinate information of the point to be measured obtained by each photogrammetric component via wired or wireless communication, and perform intersection measurement based on the transformation 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 point to be measured in the base station coordinate system. To improve measurement efficiency, the shooting and intersection measurement process of the test point in step S3 can be performed simultaneously with the shooting and intersection measurement process of the reference point in step S2. Then, step S4 is performed. In step S4, the coordinates of the reference point and the test point in the base station coordinate system calculated by the control component, and the transformation 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 test point in the world coordinate system. This allows the calculation of the world coordinates of the first test point around the reference point. Subsequent steps are then performed to measure the world coordinates of the remaining test points around the reference point. Specifically, in step S5, the relative angle between the reference point and the test point is calculated based on the coordinates of the reference point and the first test point. Here, the coordinates of the reference point and the first test point can be the coordinates of the reference point and the first test point in the world coordinate system calculated in step S4. Then, based on the calculated relative angle, the control component controls multiple rotating components to rotate their respective photogrammetry components until the shooting center of each photogrammetry component is aligned with the first test point and the next test point is within the shooting range of each photogrammetry component.Because the photogrammetric component in this invention can rotate under the drive of the rotating component, 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 obstructed and thus unable to enter the shooting range of the photogrammetric component. Therefore, compared to the fixed camera in the prior art, the measurement method provided by this invention is more flexible and less prone to obstruction of the target object, thus eliminating the need to move the position of the photogrammetric component, effectively simplifying the measurement process and improving measurement efficiency. After completing step S5, step S6 is performed to use the first point to be measured as the new reference point. Finally, step S7 is performed to repeat steps S3-S6, thereby calculating the coordinates of all points to be measured in the world coordinate system. After obtaining the coordinates of all points to be measured in the world coordinate system, the coordinates of each key point on the target object in space can be determined, thereby achieving spatial positioning of the target object. This allows for the determination of whether the three-dimensional spatial dimensions of nuclear equipment such as reactor shells meet production requirements, whether the main pipe of a nuclear power plant is deformed after welding, and whether the high-precision track of a nuclear power plant is installed in place. As can be seen, the measurement method provided by the present invention can also achieve automatic tracking and measurement of the remaining test points after the first test point through steps S3-S7, which can not only further improve the measurement efficiency, but also adjust the position of the photogrammetry component in real time to improve its measurement accuracy.

[0018] Compared with existing technologies, the measurement method provided by this invention, by employing a rotating 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 point to be measured without moving the photogrammetric component, effectively simplifying the measurement process and improving measurement efficiency. Furthermore, if the control field range increases, the photogrammetric component can also be rotated to capture the points to be measured within the increased control field, eliminating the need for additional base stations and reference points, effectively reducing workload. In addition, the measurement method provided by this invention, through steps S1-S7, can achieve automatic tracking measurement of multiple points to be measured within the control field, further improving measurement efficiency and allowing real-time adjustment of the relative position between the photogrammetric component and the reference point during automatic tracking measurement, thereby effectively improving the shooting accuracy and intersection measurement accuracy of the photogrammetric component and reducing measurement errors.

[0019] The measurement system provided by this invention applies the aforementioned measurement method. The system includes a control component, multiple photogrammetry components, and multiple rotation components. Each photogrammetry component is mounted one-to-one with one of the rotation components, and both the photogrammetry components and the rotation components are connected to the control component. Each photogrammetry component, when its shooting center is aligned with a reference point, captures images of the reference point and the point to be measured within its shooting range, obtaining the coordinates of the reference point and the point to be measured in the coordinate system of the photogrammetry component. The control component has a preset transformation relationship between the base station coordinate system and the world coordinate system, and is used to receive multiple... The photogrammetric components obtain coordinate information and perform intersection measurements based on the transformation 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 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 multiple rotating components to drive the photogrammetric components on them to rotate according to 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 measurement method, and therefore has the same beneficial effects as the above measurement method. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 A flowchart of the measurement method provided in an embodiment of the present invention; Figure 2 A central perspective projection image of the photogrammetric component during the imaging process provided in an embodiment of the present invention; Figure 3 This is a diagram illustrating the cross-ratio definition in the perspective projection transformation of a photogrammetric component provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of the structure of the rotating component and the photogrammetry component in the measurement system provided in an embodiment of the present invention.

[0022] Icons: 1-Photogrammetric component; 2-Rotation component; 20-Upper turntable; 21-Lower turntable. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can 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: Arrange reference points and multiple test points in the control field, install multiple photogrammetry components one by one on multiple rotating components, align the shooting centers of multiple photogrammetry components with the reference points, and ensure that at least one test point is within the shooting range of multiple photogrammetry components. Step S2: Select the coordinate system of one of the photogrammetric components as the base station coordinate system, use multiple photogrammetric components to take pictures of the reference point and obtain coordinate information, and calibrate the transformation relationship between the coordinate system of each photogrammetric component and the base station coordinate system based on the measurement results; Step S3: Use multiple photogrammetry components to take pictures of the points to be measured within their shooting range and obtain coordinate information. Use the control component to receive the coordinate information obtained by each photogrammetry component and perform intersection measurement based on the transformation relationship between the coordinate system of each photogrammetry component 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. 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 transformation 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 using the control component. Step S5: Calculate 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 make the control component control multiple rotating components to drive the photogrammetry components on them to rotate based on the relative angle until the shooting center of the multiple photogrammetry components is aligned with the point to be measured, and make the next point to be measured within the shooting range of the multiple photogrammetry components. Step S6: Use the point to be measured, which is aligned with the shooting center of the multiple photogrammetry components, as the new reference point; Step S7: Repeat steps S3-S6 until the coordinates of all 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 spatial dimensions of nuclear equipment such as reactor shells during nuclear engineering construction, as well as for attitude measurement and correction of nuclear equipment, or for measurement operations in tasks such as welding deformation detection of main pipelines in nuclear power plants and installation and adjustment of high-precision tracks in nuclear power plants. When measuring the aforementioned target objects such as nuclear equipment, main pipelines, and high-precision tracks, a control field can be first established in the space surrounding the target object, and then step S1 of the measurement method in this embodiment can be performed in the control field.

[0028] Specifically, in 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 its shape and orientation as multiple test points. Then, multiple rotating components and their photogrammetry components can be arranged at intervals in the control field. At this time, each photogrammetry component can be used 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 rotating component 2 and the photogrammetric component 1 shown are used. The photogrammetric component 1 can be a digital close-range photogrammetric component 1 including a camera, which has image recognition and processing functions, can identify the measurement target from multiple angles and take high-frequency pictures, and obtain the coordinates of the reference point or the point to be measured in its coordinate system based on the captured images, as well as obtain the scale information and attitude information of the measurement target; the rotating component 2 can be a theodolite including a motor, a horizontal turntable and a vertical rotating shaft, in which case the rotating component 2 can rotate in the horizontal and pitch directions.

[0030] In step S1, during the arrangement of the rotating component 2 and the photogrammetry component 1, the shooting center of each photogrammetry component 1 must be aligned with the reference point. That is, the shooting center of each photogrammetry component 1 is on the same straight line as the reference point, and the reference point is within the shooting range of multiple photogrammetry components 1. At the same time, at least one point to be measured must be located around the reference point to ensure that at least one point to be measured is within the shooting range of multiple photogrammetry 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. At the same time, multiple photogrammetric components 1 are used to take pictures of the reference point and obtain coordinate information. Since the coordinates of the reference point are known, the transformation relationship between the coordinate system of each photogrammetric component 1 and the base station coordinate system can be determined based on the coordinate information of the reference point obtained by each photogrammetric component 1. It should be noted that in step S2, the transformation relationship between the coordinate system of each photogrammetric component 1 and the base station coordinate system can be determined in real time using the control component.

[0032] Then, step S3 is performed. In step S3, the positions of 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. Subsequently, 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 transformation 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 shooting and intersection measurement process of the points to be measured in step S3 can be performed simultaneously with the shooting and intersection measurement process of the reference point in step S2. The intersection measurement process can use existing camera-based forward intersection technology or 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 is calculated using the coordinate information of the reference point and the point to be measured calculated by the control component, and the coordinates of the reference point and the point to be measured in the world coordinate system are calculated based on the transformation relationship between the base station coordinate system and the world coordinate system preset in the control component. Thus, 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 test points around the reference point. Specifically, in step S5, the relative angle between the reference point and the test point is calculated based on the coordinates of the reference point and the first test point. Here, the coordinates of the reference point and the first test point can be the coordinates of the reference point and the first test point in the world coordinate system calculated in step S4. Then, based on the calculated relative angle, the control component controls multiple rotating components 2 to drive the photogrammetry components 1 on them to rotate until the shooting center of each photogrammetry component 1 is aligned with the first test point and the next test point is within the shooting range of each photogrammetry component 1.

[0035] Since the photogrammetry component 1 in this embodiment can rotate under the drive of the rotating component 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 obstructed and unable to enter the shooting range of the photogrammetry component 1. Therefore, compared with the fixed camera in the prior art, the measurement method provided in this embodiment is more flexible and less prone to obstruction of the target object, thus eliminating the need to move the position of the photogrammetry component 1, effectively simplifying the measurement process and improving measurement efficiency. To ensure the shooting range of the photogrammetry component 1, the rotation range of the rotating component 2 in the horizontal direction can be 0° to 360°, and the pitch rotation range of the rotating component 2 can be ±120°.

[0036] After completing step S5, proceed to step S6 to use the first test point as the new reference point. Finally, perform step S7 to repeat steps S3-S6, thereby calculating 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 coordinates of each key point on the target object in space can be determined, thus achieving spatial positioning of the target object. This allows for determining whether the three-dimensional spatial dimensions of nuclear equipment such as reactor shells meet production requirements, whether the main pipeline of a nuclear power plant has deformed after welding, and whether the high-precision track of the nuclear power plant has been installed correctly.

[0037] As can be seen, the measurement method provided in this embodiment can also achieve automatic tracking and measurement of the remaining test points after the first test point through steps S3-S7. This not only further improves the measurement efficiency but also allows for real-time adjustment of the position of the photogrammetry component 1 to improve its measurement accuracy. Experimental verification shows that the measurement method provided in this embodiment, through forward intersection measurement technology and multi-base station joint calibration technology during automatic tracking and measurement, can improve the measurement accuracy to 15μm +20μm / m (where 15μm is a fixed error and 20μm / m is a proportional error), making it suitable for various high-precision measurement scenarios. Furthermore, the measurement method provided in this embodiment, through the cooperation between the photogrammetry component 1 and the control component, can effectively shorten the time from test point acquisition to display of measurement results, controlling the response time to within two seconds, effectively meeting the needs of real-time measurement.

[0038] Compared with existing technologies, the measurement method provided in this embodiment, by employing a rotating component 2 in step S1, can expand the shooting range of each photogrammetric component 1, thereby flexibly adjusting the relative position between the photogrammetric component 1 and the point to be measured without moving the position of the photogrammetric component 1, effectively simplifying the measurement process and improving measurement efficiency. Furthermore, if the control field range increases, the photogrammetric component 1 can also be rotated to capture the points to be measured within the increased control field, eliminating the need for additional base stations and reference points, effectively reducing workload. In addition, the measurement method provided in this embodiment, through steps S1-S7, can achieve automatic tracking measurement of multiple points to be measured within the control field, further improving measurement efficiency and allowing real-time adjustment of the relative position between the photogrammetric component 1 and the reference point during automatic tracking measurement, thereby effectively improving the shooting accuracy of the photogrammetric component 1 and reducing measurement errors.

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

[0040] In this embodiment, the photogrammetry component 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. Since the image acquisition unit, image data preprocessing unit, and power supply unit generate heat during photogrammetry, which can affect measurement accuracy, this embodiment preferably includes a heat dissipation structure in the photogrammetry component 1. This heat dissipation structure can effectively reduce the interference of the photogrammetry component 1's own heat on the measurement results, further improving measurement accuracy. Specifically, the heat dissipation structure can reduce thermal resistance by shortening the heat transfer path, increasing the thermal conductivity, and increasing the thermal conductivity.

[0041] The camera selected in the photogrammetry component 1 is typically based on a stable solid-state image sensor, whose performance parameters directly affect the measurement results. Therefore, this embodiment preferably calibrates the digital camera used in the photogrammetry component 1. The camera's interior orientation elements and lens optical distortion coefficients are collectively referred to as camera intrinsic parameters, and the exterior orientation elements are referred to as camera extrinsic parameters. The camera's intrinsic and extrinsic parameters can be preset in the photogrammetry component so that the photogrammetry component obtains coordinate information based on these intrinsic and extrinsic parameters and the images it captures.

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

[0043] Regarding the radial distortion parameter of a lens: Radial distortion is the deviation of the image point along the radial direction. Radial distortion is symmetrical; the center of symmetry does not completely coincide with the principal point, but the principal point is usually considered the center of symmetry. Radial distortion can be positive or negative; an outward shift relative to the principal point is positive, and an inward shift is negative. Wide-angle lenses (ƒ<50mm) typically exhibit negative distortion, standard lenses (ƒ=50mm) can have both positive and negative distortion, and medium telephoto (80mm<ƒ<150mm) and telephoto (ƒ>150mm) lenses mostly exhibit positive distortion. Moreover, standard lenses have the least distortion, and the shorter (or longer) the focal length, the greater the distortion.

[0044] Radial distortion can be represented by the following odd-degree polynomial:

[0045] Decompose it onto the x-axis and y-axis of a planar coordinate system, then we have:

[0046] In the formula: K1, K2, and K3 are radial distortion coefficients; .

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

[0048] For lens eccentricity distortion parameters: Lens eccentricity distortion is the eccentricity distortion caused by the center of the lens group deviating from the principal optical axis. Eccentricity distortion causes both radial and tangential deviations in the image point, and its expression is as follows:

[0049] Decompose it onto the x-axis and y-axis of a planar coordinate system, then we have:

[0050] In the formula: P1 and P2 are the eccentricity distortion coefficients.

[0051] Eccentric distortion is much smaller in number than radial distortion. Since the solution process for eccentric distortion is also existing technology, its specific solution process will not be described in detail here.

[0052] For in-plane distortion parameters: In-plane distortion is the planar distortion of image points within the image plane caused by A / D conversion and signal transfer errors due to asynchronous sampling clocks of pixels. It can usually be simplified to the distortion caused by the pixel's aspect ratio and the non-orthogonality of the image plane's x-axis and y-axis, and its expression is as follows:

[0053] In the formula, b1 and b2 are the distortion coefficients in the image plane. Since the solution process for the distortion parameters in the image plane is also existing technology, its specific solution process will not be described in detail here.

[0054] For the interior orientation element error parameter: if the interior orientation element used is (x0, y0, ... Inaccuracy 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 derived as:

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

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

[0057] Taking into account the influence of systematic errors at image points, the collinearity equation can be written as:

[0058] In the formula: 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; Focal length; The elements of the rotation matrix are, and the correspondence is as follows: .

[0059] In practical applications, camera intrinsic parameters can also be determined using the test field calibration method. Specifically, a test field is first constructed using a large number of control points with known 3D coordinates. Then, calibration images are taken at multiple positions and angles within the test field using the camera to be calibrated. Finally, the camera intrinsic parameters are solved using the resection method. The test field calibration method utilizes a large number of high-precision control points for spatial resection to directly compensate for systematic errors at image points. Its advantages include relatively accurate correction of systematic errors, simple calculation, low requirements for photographic geometry, minimal impact from the correlation between intrinsic and extrinsic parameters, and the ability to evaluate the quality of calibration results.

[0060] The camera's external parameters can be determined as follows: A collimating cube mirror is installed on the camera, and the camera is placed on the rotating assembly 2, ensuring that the camera's X-axis is approximately horizontal with the horizontal axis of the rotating assembly 2, and the camera's Y-axis is approximately horizontal with the vertical axis of the rotating assembly 2. The camera is then aimed at a reference point within the control field for measurement, and the camera's position and attitude are calculated using the resection principle. A coded point is then attached above the camera lens. The camera is rotated horizontally, and measurements are taken every 10° to calculate the coordinates of this point in the control field coordinate system. The camera is then rotated horizontally for one full rotation, and multiple coordinate values ​​at multiple positions in the control field coordinate system are fitted to a circle. The camera is then rotated vertically for one full rotation, and another circle is fitted. The intersection of the normals of the two circles is the origin of the coordinate system of the rotating assembly 2, thus calibrating the coordinate system of the rotating assembly 2. Finally, a theodolite measurement system is used to simultaneously aim at the cube mirror and the control point to calculate the transformation relationship between the camera's coordinate system and the coordinate system of the rotating assembly 2.

[0061] Therefore, when calculating the coordinates of the reference point and the point to be measured in the world coordinate system, when considering the camera's intrinsic parameters, it is necessary to compensate for the systematic errors caused by the camera's intrinsic parameters in the calculation process; when considering the camera's extrinsic parameters, it is necessary to transform between 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 be preset in the control component, and the coordinates of the reference point and the point to be measured in the world coordinate system can be calculated 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 transformation relationship between the base station coordinate system and the world coordinate system.

[0063] The rotating component 2 inevitably introduces errors during instrument manufacturing and use. Therefore, these errors need to be considered in the calculation process to further improve measurement accuracy. Based on this, this embodiment preferably presets error compensation parameters in the control component.

[0064] Among them, the rotating component 2 is a theodolite. Based on the structure of the theodolite, the error can be divided into grating error, reading system error, shaft system and eccentricity error, and tilt sensor error.

[0065] Regarding grating errors: Grating errors include diameter error, grating tilt error, and grating deformation error. Diameter error is a manufacturing error in the dial diameter caused by process limitations. This error can be automatically eliminated after six or more measurements as required, and therefore does not need to be included in the calculation. Grating tilt error refers to the dial not being perpendicular to the vertical axis and the optical axis of the reading system not being perpendicular to the dial; this is negligible and does not need to be included in the calculation. Grating deformation error is the error caused by heat deformation of the dial; this error can be resolved through heat dissipation and also does not need to be included in the calculation.

[0066] Regarding the errors in the reading system: These errors include eccentricity errors in the grating division, errors due to imperfect orthogonality of the gratings, and errors during subdivision quantization. The errors in the reading system can be resolved by averaging the readings, and therefore do not need to be included in the calculation process.

[0067] Regarding axis system and eccentricity errors: These errors include axis system errors and eccentricity errors. Axis system errors arise from situations during actual use of the theodolite, such as the line of sight not being perpendicular to the horizontal axis, the horizontal axis not being perpendicular to the vertical axis, or the vertical axis not being perfectly plumb. This error refers to the measurement errors in horizontal and vertical angle measurements caused by axis system tilt during the theodolite's angle measurement process. Eccentricity errors are caused by eccentricity in both the theodolite's scale circle and axis system. Eccentricity errors are divided into errors caused by angle encoder eccentricity and errors caused by albedo eccentricity. Angle encoder eccentricity can be eliminated by using a calibrated reading head, so it does not need to be included in the calculation. Errors caused by albedo eccentricity refer to the eccentricity of the theodolite's albedo and the eccentricity of the horizontal grating; their impact is significant, therefore they must be included in the calculation. It should be noted that this part of the error is also a major reason why angle measurement accuracy is difficult to improve.

[0068] Regarding the tilt sensor error: This error refers to the leveling error caused by the tilt sensor to the theodolite. The leveling error will affect the observation results, so it is necessary to correct the leveling error during the calculation process.

[0069] Based on the aforementioned shaft system and eccentricity errors, tilt sensor errors that need to be corrected, the aforementioned 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 errors, the aforementioned three parameters can be calculated first and preset in the control component to form an error correction program, so that the aforementioned error compensation parameters can be included in the calculation process, thereby improving the accuracy of the final coordinate calculation of the measured point.

[0070] In this embodiment, the calculation process of the error compensation parameters is as follows: The error caused by the tilt of the vertical axis and the error caused by the tilt of the horizontal axis are based on the same principle. The tilt of the vertical axis actually causes the horizontal axis to tilt as well; numerically, it only increases the tilt of the horizontal axis by iv= ×cosβ′ (iv is the tilt angle of the horizontal axis caused by the tilt of the vertical axis, Let β' be the vertical axis tilt error and β′ be the measured horizontal grating reading. Therefore, when correcting the axis system error, it is only necessary to add the 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 components 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 tilt angle). In fact, the error caused by the vertical tilt and the error caused by the horizontal tilt have the same result, and there is no need to correct it separately. It can be corrected simply by treating it as a component of the horizontal tilt.

[0071] When measuring the point to be measured, the existing left-right positioning method can be used to counteract the influence of the line of sight and the horizontal axis on the measurement angle. Therefore, the mathematical formula for the error caused by axis tilt is as follows:

[0072] In the formula: β and α are the accurate horizontal and vertical angle values ​​at the measurement point; , These are the actual horizontal and vertical angle values ​​measured at the measurement point. , These are the horizontal and vertical angle error values ​​at the measurement points caused by the tilt of the shaft system. in:

[0073]

[0074] In the formula: This refers to the vertical axis tilt error; Substituting formula (12) into formula (10) and formula (13) into formula (11), we get:

[0075] The calculation process for eccentricity error in 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 and vertical angles. Therefore, the correction formula for the eccentricity error can be obtained as follows:

[0076] In the formula: , η represents the horizontal and vertical angle error values ​​at the measurement point caused by the eccentricity of the aiming part; e represents the eccentricity amplitude (eccentricity distance from the center) of the aiming part of the rotating assembly 2; η represents the eccentricity phase of the aiming part of the rotating assembly 2. The radius of the horizontal grating in rotating component 2 is a known value; The conversion constant for converting radians to the angle unit "arcsecond". =206264.806".

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

[0078] In the formula: , These are the total error values ​​for the horizontal angle and the total error values ​​for the vertical angle at the measurement point; Considering various factors, only the vertical axis error and eccentricity error need to be corrected, then:

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

[0080] in, , The values ​​of v, e, and η can be obtained directly by measuring the readings. Therefore, the specific values ​​of v, e, and η can be determined and error compensation can be performed using formulas (22) and (23). At this time, the values ​​of v, e, and η can be obtained by direct measurement and indirect measurement methods. However, the direct measurement method will introduce new errors caused by defects such as equipment inherent errors. Therefore, in this embodiment, the indirect calculation method is preferred to calculate the parameters v, e, and η.

[0081] The calculation principle of the indirect calculation method is to first treat the systematic error as an invariant value. Correspondingly, the parameters v, e, and η that cause the systematic error are also invariant values. Then, the angle measurement value is obtained by measuring the angle of multiple known angle measurement points. The error value between the known angle value and the measured angle value is then calculated. At this time, there are multiple error values. Substituting the multiple error values ​​into formulas (22) and (23) respectively, a system of linear equations in one variable including three unknowns (v, e, η) can be obtained. Solving this system of equations will yield the values ​​of the parameters v, e, and η.

[0082] For example, using the theodolite in this embodiment, actual measurements are taken at three measurement points with known angle values. The known angle values ​​of the three measurement points are as follows: The angle values ​​of the three measurement points were measured as follows: After substituting the known angle value and the measured angle value of each measurement point into formulas (22) and (23) respectively, each measurement point can obtain a set of values ​​containing... , , A function of unknowns can be solved by three linear equations in one variable (each containing three unknowns). , , .

[0083] It can be seen that the above error compensation parameters can be calculated by actually measuring multiple known angle values ​​at known measurement points and then combining them with formulas (22) and (23). The meanings of the parameters in the formulas are as follows: The eccentricity amplitude of the aiming part of the rotating assembly 2, For the eccentric phase of the aiming part of rotating component 2, The vertical axis tilt error of rotating component 2; Given the vertical angle value of the measurement point, The horizontal angle value of the known measurement point; The vertical angle value is the value measured when a known measurement point is actually measured. This refers to the horizontal angle value measured during actual measurement of a known measurement point; The radius of the horizontal grating in rotating component 2; The conversion constant for converting radians to the angle unit "arcsecond". =206264.806".

[0084] In this embodiment, the rotating component 2 may be 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 process 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.

[0085] During use, the angle measurement module can measure the angle rotated by the rotating component 2 in real time and feed the angle back to the control component in real time. This makes it easier to control the rotating component 2 to stop rotating in time 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, 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 the absolute photoelectric encoder does not require a counter, responds promptly, and overcomes the cumulative reading error, this embodiment preferably uses a high-precision absolute photoelectric encoder for the angle measurement module.

[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 to form a scale on a bright substrate, 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 commands from the control component. When receiving commands, the reading head can calculate the position using two independent methods to avoid the risk of failure due to common causes. Therefore, compared with the existing ordinary absolute encoder, the high-precision photoelectric absolute encoder in this embodiment can significantly improve the measurement accuracy.

[0089] To further ensure angular measurement accuracy, this embodiment preferably employs a non-contact open grating design for the high-precision photoelectric absolute encoder. This design avoids non-repeatable errors such as connector gaps, shaft runout, and mechanical hysteresis found in traditional absolute encoders. Experimental verification shows that the measurement accuracy of both the horizontal and vertical angles of the high-precision photoelectric absolute encoder in this embodiment is no greater than 4".

[0090] Furthermore, the rotating component 2 can also be equipped with a touchscreen that matches the control component. This touchscreen can have buttons for taking photos and other convenient measurement tasks. Simultaneously, the touchscreen can display the coordinate results calculated by the control component in real time, allowing operators to know the world coordinates of the current measurement point. Furthermore, the touchscreen can also display the three-dimensional coordinates, dimensions, and orientation of target objects such as nuclear equipment in real time based on the calculation and analysis results of the control component. It should be noted that, to improve the ease of use of the touchscreen, it can also be mounted on a handheld terminal.

[0091] In this embodiment, the control component can not only generate information such as the three-dimensional coordinates, size, and posture of the target object based on the world coordinates of the point to be measured, but also 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 the intersection measurement uses the camera-based forward intersection technique, in this embodiment, the rotating component 2 is preferably also equipped with a laser ranging component. When performing intersection measurement, the existing linear equations between the actual and ideal image points can be used to solve the problem based on the least squares method to determine the three-dimensional coordinates of the point to be measured. The geometric meaning of this least squares solution is that the sum of the squares of the distances from the intersection point of multiple photogrammetry components 1 to the family of spatial rays determined by the optical centers and image points of each photogrammetry component 1 is minimized. In the case of the intersection of two photogrammetry components 1, their spatial intersection point is the midpoint of the common perpendicular segment of these two spatial rays. At this time, the laser ranging component can be used to measure the distance to provide an accurate initial distance value, and then the high-precision three-dimensional coordinates can be obtained by bundle adjustment, thereby further improving the accuracy of coordinate calculation.

[0093] Furthermore, the laser ranging component can also be used to illuminate a 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. This allows the laser ranging component to determine whether the shooting center of the photogrammetry component 1 is aligned with the point to be measured by accurately illuminating the calibration point, thereby further ensuring the accuracy of photogrammetry.

[0094] Based on this, step S50 can also be 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 points illuminating the periphery of the calibration point, calculate the coordinates of the calibration point and the laser points in the coordinate system of the photogrammetry component 1 based on the captured images, and then calculate the deviation angle between the calibration point and the laser points based on the coordinates. The control component controls 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] The measurement point can be a moving target, and the calibration point can be a cooperative target formed by fusing a prism target sphere and photogrammetric markers. Specifically, the moving target can be an approximate sphere with multiple planes, each plane serving as a measurement surface. Encoded markers and circular measurement markers are affixed to the measurement surfaces. The approximate spherical structure ensures that the photogrammetric component 1 can observe the corresponding markers on the measurement surfaces from any angle. Furthermore, a measurement probe can be installed below the moving target. The measurement probe can be 1000 mm long, and the probe head can be made of materials such as silicon nitride, zirconium oxide, and ruby, with the material selection based on actual needs. Since the moving target is a rigid structure, there is a fixed spatial distance relationship between each marker on each measurement surface and the probe head. The distance matrix between each marker on the measurement surface and the probe head can be calculated.

[0096] To improve recognition efficiency and positioning accuracy, the above-mentioned signs can be retroreflective signs. Retroreflective signs are composed of glass microspheres, base adhesive, substrate and backing adhesive. Glass microspheres are used for reflection. The advantage of glass microspheres is that they can produce high-contrast images with low-intensity exposure. Their reflectivity is 100 to 1000 times higher than that of ordinary white signs under the same lighting conditions.

[0097] The reflective markers made of glass microspheres form a clear and prominent image on the photogrammetry component 1, appearing as a group of circular or elliptical bright spots. The size of the reflective marker image directly affects the measurement accuracy. Too few pixels affect extraction accuracy, while too many pixels cause eccentricity problems. Therefore, in this embodiment, the preferred 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 image include: the distance between the marker and the camera, the lens focal length, the camera resolution, and the pixel size. The maximum measurement distance between the marker and the camera is set to 10m. Based on the camera's field of view, resolution, and pixel size, the lens focal length is calculated to be 25mm. Then, based on the pinhole imaging principle, (4.5×10) 3 ) / D=25 / (10×10 3Therefore, the spatial resolution D of the camera at a position of 10m is calculated to be 1.8mm. Taking the number of pixels occupied by the sign in the image as 7 as an example, the diameter of the sign is further calculated to be 1.8×7=12.6mm.

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

[0099] The edge detection operator operates as follows: First, a Gaussian filter is used to filter the image to eliminate image noise; second, the magnitude and direction of the image gradient are calculated using the finite difference method of the first-order partial derivative; third, maximum suppression is performed on the gradient values ​​calculated in the second step; fourth, a double threshold algorithm is used to detect the image edges and connect the detected edges.

[0100] The steps of edge tracking are as follows: First, obtain the starting pixel for searching the boundary of a certain region. Take the first pixel P0 of a new region as the starting pixel for the boundary search, and define a variable `dir` to store the movement direction. Each pixel's neighborhood has eight directions. Second, search the 3x3 neighborhood of the current pixel in a counter-clockwise direction. The starting search direction is selected according to the following principle: if `dir` is odd, divide (dir+6) by 8, and use the remainder as the starting search direction; if `dir` is even, use (…). +7) Divide by 8, and use the remainder as the starting search direction. Update the variable 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 is also the value of the new boundary point P that is being searched. n The third step is to determine the edge pixel P located at the current position. n It equals the second edge pixel P1, while the previous edge pixel P n-1 If the value equals P0, stop the search and complete this edge tracking step; otherwise, repeat step two.

[0101] The steps to determine the center ellipse of the marker are as follows: First, perform perimeter, aspect ratio, area, and circularity (shape factor) checks on the edges of the black hole and "bright spot" obtained after edge detection and edge tracking; Second, perform pixel grayscale checks on the image.

[0102] The gray-scale weighted centroid algorithm is an existing technology, so the specific calculation process for determining the marker center using the gray-scale weighted centroid algorithm will not be described in detail here.

[0103] After determining the center of the marker, it is necessary to identify the markers with coded information (the coded information is made according to pre-set rules), and complete the matching of the same point of a single point. Finally, the resection calculation is performed based on the information of each photo to determine the pose of each photo and complete the relative orientation of multiple photos.

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

[0105] The analysis and calculation process for the principle of perspective projection is as follows: The imaging process is a projection from three-dimensional space to a two-dimensional plane, that is, projecting a certain attribute of a spatial object onto a plane according to a certain rule to form an image. This process is usually called 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 formation of an image by a real camera can be simulated using a central perspective model, that is, a point in three-dimensional space is projected onto the image plane to produce a corresponding image point. All projection lines and the extensions of the lines connecting the measured point and its image point intersect at a point, which is the projection center. Figure 2 This is a central perspective projection image of the photogrammetric component 1 during the imaging process provided in this embodiment, such as... Figure 2 As shown, a three-dimensional coordinate system XYZ is selected, with the origin O at the projection center (also called the perspective center), the optical axis as the Z-axis, and the image plane as 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. The X-axis and Y-axis are parallel to the x-axis and y-axis, respectively. Then, the coordinates of a point (X,Y,Z) in three-dimensional space and its image point (x,y) have the following nonlinear perspective transformation relationship:

[0106] In three-dimensional space, different viewpoints of a camera relative to the same target will cause changes in the target's orientation and posture relative to the camera. These changes will alter the image of the target 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 to the object's plane, the relative motion of the camera or object will cause rotation and translation changes in the object's image. Changes in the distance between the camera and the object will cause changes in the size of the object's image. In practical applications, it is obviously difficult to ensure that the relative distance and orientation between the measured object and the camera remain constant. Identifying point-based coded markers requires matching the point set extracted from the image with template points to restore the coordinate system of the coded marker design. The coded markers undergo affine transformations or perspective projection transformations such as rotation, translation, scaling, and distortion in the photographic image, thus involving affine transformation and perspective projection transformation problems in computer vision.

[0107] The analysis and calculation process for affine transformations is as follows: In Euclidean space, a mapping that transforms three collinear points into three collinear points is called an affine transformation. An affine transformation consists of six parameters. If, in a plane, an affine transformation transforms one shape into another, then the two shapes are said to be affine equivalent. It can be proven that: 1. Any two triangles located in the same plane are affine equivalent; 2. Any two tetrahedrons located in the same space are affine equivalent. Based on this, an affine transformation can be written in matrix form as follows:

[0108] in, These 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 rays from the scene pass through a projection center, which corresponds to the center of the lens. Perspective projection transformation has two more parameters than affine transformation, for a total of eight parameters. The perspective projection transformation can be written in matrix form as follows:

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

[0111] The analysis process for projection transformation invariants (i.e., cross ratios) is as follows: Cross ratios are invariants in projection transformations. A one-dimensional cross ratio is defined based on the distance between four points on the same straight line. Figure 3 This is the cross-ratio definition diagram in the perspective projection transformation of the photogrammetric component 1 provided in this embodiment, by... Figure 3It can be seen that the cross ratio of four points (A, B, C, D) on the same straight line L is defined as:

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

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

[0114] In the formula: These represent the angles between each pair of adjacent projection lines OA, OB, OC, and OD, respectively. Figure 3 As shown.

[0115] From formulas (27), (28), and (29), we can obtain:

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

[0117] When the distance between the planar target and the camera is relatively small, the projected lines are approximately parallel, and affine transformation can be used to approximate the central perspective of the plane. For the same scene (whether two-dimensional or three-dimensional), the geometric shape of the images taken by the camera at different locations and from different angles is different. Although the geometric shapes of these images are different, the geometric deformation between any two images can be described by projective transformation. When the distance between the camera and the scene is much larger than the size of the scene, projective transformation can be approximated by affine transformation.

[0118] Point-based coded marker recognition can be viewed as a matching problem of point sets in two images. The recognition method involves finding the image points of the template points in the image using designed template points, then restoring the points in the image to the designed coordinates through an affine transformation, and simultaneously calculating the affine transformation parameters. The image points of the coded points surrounding the template points are then recovered using the affine transformation parameters, and compared with the designed coordinates to decode the coded points and obtain the code of the coded marker.

[0119] When matching corresponding points of a single-point marker, the epipolar matching algorithm from 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 that image point on other images must lie on its corresponding epipolar line. If the exact or approximate value of the orientation parameter is known, the corresponding epipolar line can be calculated. The calculation process is as follows: Taking three photogrammetric components 1 (i.e., three base stations) as an example, For the optical center of each base station lens, For each image plane, For each principal point, Let P be the corresponding image point of the object point. For image points exist The corresponding epipolar line on the image. Let the coordinates of a point in the image space coordinate system of base station No. 1 be... Its coordinates in the image space coordinate system of base station No. 2 are: Then the following equation holds:

[0120] In the formula: M1 and M2 are the rotation matrices of base station 1 and base station 2 relative to the object space coordinate system. The translation parameters of base station 1 and base station 2 in the object space coordinate system .

[0121] Furthermore, because in the image space coordinate system of base station number one, The coordinates are known values, respectively. and Therefore, according to formula (31), we can obtain The coordinates in the image space coordinate system of base station No. 2 are respectively: , .

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

[0123] In the image space coordinate system of base station No. 2, the plane equation of image plane I2 is:

[0124] Substituting equation (33) into equation (32), we obtain the image point. epipolar line I on image plane I2 12 The equation is:

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

[0126] Similarly, we can obtain the image points. Epipolar line I on image plane I3 13 The equation is given, and its specific calculation process will not be elaborated here.

[0127] After identifying the markers with coded information and completing the matching of corresponding points for a single point using the above method, the identification accuracy of the markers can be effectively guaranteed, thereby effectively improving the calculation accuracy during the resection calculation based on the photo information.

[0128] It should be noted that the measurement method provided in this embodiment is based on spatial positioning measurement of the point to be measured using multiple base stations, belonging to multi-view stereo vision measurement. Its data processing is based on the collinearity condition equation, and the data processing mode can be divided into two modes: 1. A step-by-step mode of orientation followed by coordinate measurement; 2. A holistic solution mode where orientation and coordinate measurement are performed simultaneously. The step-by-step measurement mode is based on the calculation process of single-image spatial resection and multi-base station spatial forward intersection using the collinearity equation. The holistic solution mode treats the image coordinates of the control points, the image coordinates of the point to be determined, and other data (such as relative control) as observation values, and solves the exterior orientation elements of the image and the spatial coordinates of the point to be determined as a whole. This is also the bundle adjustment method in photogrammetry, or simply bundle adjustment. When calculating the spatial coordinates of the point to be measured, one of the above two data processing modes can be selected. Since both of these data processing modes are existing technologies, their specific calculation processes will not be described in detail here.

[0129] In this embodiment, the control component can be composed of components such as a power supply module, a GNSS module, a remote control module, a display module, a logic control module, a signal output module, and an outer frame. The logic control module is an integrated circuit (PCB board) housing an FPGA chip, a level conversion chip, a signal conversion chip, a superheterodyne RF signal receiver chip, a power supply chip, and related peripheral designs; it is the core board for processing digital signals. Therefore, the control component provided in this embodiment uses a mature and reliable FPGA chip to architect the entire system, and the control component supports wireless connectivity, superheterodyne RF control, and direct connection control to a host computer.

[0130] In summary, the measurement method provided in this embodiment employs 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 the points to be measured, a multi-point intersection method is used, which can accurately calculate the spatial coordinates of the points. This measurement method can automatically track and measure multiple points to be measured (multiple points can be obtained by arranging multiple targets or by gradually moving a moving target). This measurement method greatly improves the automation of the measurement process, enabling efficient and high-precision measurements in complex environments.

[0131] This embodiment also provides a measurement system that applies the above-described measurement method. The system includes a control component, multiple photogrammetry components 1, and multiple rotation components 2. Each photogrammetry component 1 is mounted one-to-one with one of the rotation components 2, and both the photogrammetry components 1 and rotation components 2 are connected to the control component. Each photogrammetry component 1 is used to photograph a reference point and a point to be measured within its shooting range when its shooting center is aligned with a reference point, and to obtain the coordinates of the reference point and the point to be measured in the coordinate system of the photogrammetry component 1. The control component has a preset transformation relationship between the base station coordinate system and the world coordinate system. The control component is used for... The system receives coordinate information from multiple photogrammetric components 1 and performs intersection measurements based on the transformation 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 calculates 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 multiple rotating components 2 to drive the photogrammetric components 1 on them 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-described measurement method. Therefore, this measurement system and the above-described measurement method can solve the same technical problems and achieve the same technical effects, which will not be elaborated further here.

[0133] The control component includes an error compensation parameter module. The error compensation parameter is preset with error compensation parameters. 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 transformation relationship between the base station coordinate system and the world coordinate system.

[0134] During coordinate measurement using this system, the system is first started to ensure normal operation. Then, preliminary calibration of each photogrammetric component 1 is performed to determine its respective coordinate system and the base station coordinate system. Next, the relative positional relationship between photogrammetric component 1 and rotation component 2 is calibrated. Then, multiple images of the target area are automatically captured using multiple photogrammetric components 1, acquiring the spatial coordinates of image markers on the target at the reference point and the point to be measured in the base station coordinate system. Subsequently, the error compensation parameter module and multi-source data fusion processing module in the control component perform error compensation, forward intersection measurement calculations, and adjustment calculations on the data measured by each module in the system, outputting accurate three-dimensional coordinates of the point to be measured. The camera's intrinsic and extrinsic parameters can be incorporated into the measurement process using the control system built into 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, both of which include a rotation output end. The central axis of the rotation output end of the upper turntable 20 is a horizontal axis, and the photogrammetry assembly 1 is mounted on the rotation output end of the upper turntable 20. The upper turntable 20 is used to drive the photogrammetry assembly 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, and the upper turntable 20 is mounted on the rotation output end of the lower turntable 21. The lower turntable 21 is used to drive the upper turntable 20 and the photogrammetry assembly 1 to rotate around the central axis of its rotation output end.

[0136] The rotation of both the upper turntable 20 and the lower turntable 21 can be achieved by rotation drive components such as motors. The upper turntable 20 can control the rotation of the photogrammetry component 1 on it according to the instructions of the control component, achieving high-precision position rotation of the photogrammetry component 1 in the pitch direction, and simultaneously outputting real-time pitch angle information. Similarly, the lower turntable 21 can control the rotation of both the upper turntable 20 and the photogrammetry component 1 on it according to the instructions of the control component, achieving high-precision position rotation of the photogrammetry component 1 in the horizontal direction, and simultaneously outputting real-time horizontal angle information.

[0137] As can be seen, the upper turntable 20 is the base of the horizontal axis system of the rotating component 2, and the lower turntable 21 is the base of the vertical axis system of the rotating component 2. To ensure the shooting range of the photogrammetry component 1, this embodiment preferably has a horizontal measurement range of 0° to 360° and a pitch measurement range of -120° to 120°. In addition, the horizontal angle measurement accuracy and vertical angle measurement accuracy of the rotating component 2 are both no greater than 4".

[0138] Furthermore, the lower turntable 21 can be fixed on a tripod, at which point the rotating component 2 can be precisely installed at the control point using the optical centering device on the tripod. In addition, the rotating component 2 can be equipped with a leveling structure. Specifically, the rotating component 2 can be coarsely leveled using a circular leveling bubble and finely leveled using a strip leveling bubble, thereby making the photogrammetric component 1 parallel to the horizontal plane of the earth. During the rotation of the photogrammetric component 1 driven by the rotating component 2, the change in rotation angle is measured in real time by the angle measurement module on the rotating component 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 angular contact bearings and mounting structures, a torque motor, and a motor driver. The inner frame angle measurement unit includes a programmable board, a reading head, and a circular grating. The inner frame power management module supplies power to all electrical components of the upper turntable 20 and also provides power to the photogrammetry component 1. The programmable board controls the motor driver according to control commands from the control component. The programmable board can also synchronously send the pose and trigger signals of the inner frame rotation unit to the control component.

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

[0141] To ensure 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, and install the bearing's outer ring screws using the cross-hatching method. After the angular contact bearing is installed, use a dial indicator and a micrometer to measure the bearing's radial runout and bushing, requiring the radial runout and bushing to reach 2u; the bearing's inner ring and the upper turntable 20 are fitted with an overfit. After chamfering the vertical shaft of the upper turntable 20 into the bearing's inner ring, fix it with screws and also use the cross-hatching method for installation. After installation, use a dial indicator and a micrometer to measure the radial runout and bushing of the upper turntable 20, requiring it to reach 2u; after the circular grating and grating reading head of the lower turntable 21 are installed, the runout of the outer ring of the circular grating should be within 0.01. Adjust the grating runout accuracy by adjusting the grating mounting screws, and ensure that the distance between the reading head and the grating is 0.8±0.15mm.

[0142] To ensure the rotational accuracy of the rotating component 2, the mechanical design accuracy of the rotating component 2 can be controlled in advance. The mechanical design accuracy of the rotating component 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 shaft eccentricity and shaft tilt. For the shaft eccentricity and shaft tilt, the accuracy of the design shaft of the angular contact ball bearing of the upper turntable 20 must be controlled within 1µm in cylindricity and 1µm in perpendicularity. The angular contact ball bearing is also subjected to interference fit, while ensuring that its radial runout is at most 1µm. In addition, taking into account the eccentricity error and tilting error, the overall runout value of the upper turntable 20 is controlled within 8µm, and the runout at the grating end is within ±5µm, thereby ensuring that the structural mechanical design accuracy is 27.47 arcseconds.

[0144] The accuracy of the lower turntable 21 is also reflected in the shaft eccentricity and shaft tilt. For both shaft eccentricity and tilt, the design accuracy of the angular contact ball bearing of the lower turntable 21 must be controlled to a cylindricity of 2µm and a perpendicularity of 2µm. An interference fit should be used to ensure a maximum radial runout of 2µm. Considering both eccentricity and tilting 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 arcseconds. Furthermore, based on the rigidity analysis of the lower turntable 21 itself and the bearing rigidity deformation caused by the load, a rigid material is preferred for the lower turntable 21, ensuring that the deformation caused by the load torque is within 1µm.

[0145] The rotational angular acceleration needs to consider the rotational angular acceleration of the upper turntable 20 and the lower turntable 21. In this embodiment, the preferred motor torque of the upper turntable 20 is 1.2 N*m, and the rotational friction torque of the upper turntable 20 is 0.5 N*m. Substituting these values ​​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 = 100 rad / s² 2 Where 1 rad = 57.3°. In this embodiment, the preferred motor torque of the lower turntable 21 is 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 values ​​into the formula for calculating rotational angular acceleration, the rotational angular acceleration of the lower turntable 21 is: ε = T / J = (2.46 - 1.4 - 0.1) / 0.07 = 13.5 rad / s² 2 , where 1 rad = 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 precision of the rotating component 2.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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: Arrange reference points and multiple test points in the control field, install multiple photogrammetry components (1) one by one on multiple rotating components (2), and align the shooting centers of multiple photogrammetry components (1) with the reference points, and ensure that at least one test point is within the shooting range of multiple photogrammetry components (1). S2: Select the coordinate system of one of the photogrammetric components (1) as the base station coordinate system, use multiple photogrammetric components (1) to take pictures of the reference point and obtain coordinate information, and calibrate the transformation relationship between the coordinate system of each photogrammetric component (1) and the base station coordinate system based on the measurement results. S3: Use multiple photogrammetry components (1) to take pictures of the points to be measured within their shooting range and obtain coordinate information. Use the control component to receive the coordinate information obtained by each photogrammetry component (1) and perform intersection measurement based on the transformation relationship between the coordinate system of each photogrammetry 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. 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 transformation 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 using the control component. S5: Calculate 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 make the control component control multiple rotating components (2) to drive the photogrammetry components (1) on them to rotate based on the relative angle until the shooting center of the multiple photogrammetry components (1) is aligned with the point to be measured, and make the next point to be measured within the shooting range of the multiple photogrammetry components (1). S6: The point to be measured, aligned with the shooting center of the multiple photogrammetry components (1), is taken as the new reference point; S7: Repeat steps S3-S6 until the coordinates of all points to be measured in the world coordinate system are calculated. 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 transformation 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. The rotating component (2) is a theodolite, and the error compensation parameters 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).

2. The measurement method according to claim 1, characterized in that, In the photogrammetry component (1), camera intrinsic parameters and camera extrinsic parameters are preset so that the photogrammetry component (1) can obtain coordinate information based on the camera intrinsic parameters, camera extrinsic parameters and the images it captures.

3. The measurement method according to claim 2, characterized in that, 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 and attitude parameters of the photogrammetry component (1) in the world coordinate system.

4. The measurement method according to claim 1, characterized in that, The error compensation parameter is calculated by actually measuring multiple known angle values ​​at known measurement points and combining the following two formulas: In the formula, The eccentricity amplitude of the aiming part of the rotating assembly (2), For the eccentric phase of the aiming part of the rotating assembly (2), The vertical axis tilt error of the rotating component (2); Given the vertical angle value of the measurement point, The horizontal angle value of the known measurement point; The vertical angle value is the value measured when a known measurement point is actually measured. This refers to the horizontal angle value measured during actual measurement of a known measurement point; The radius of the horizontal grating in the rotating assembly (2); The conversion constant for converting radians to the angle unit "arcsecond". =206264.806".

5. The measurement method according to any one of claims 1-3, 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 process 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.

6. A measurement system, employing the measurement method as described in any one of claims 1-5, characterized in that, It includes a control component, multiple photogrammetric components (1) and multiple rotation components (2); Multiple photogrammetric components (1) are installed one-to-one on multiple rotating components (2), and both the multiple photogrammetric components (1) and the multiple rotating components (2) are connected to the control component; the photogrammetric component (1) is used to take pictures of the reference point and the point to be measured within its shooting range when its shooting center is aligned with the reference point, and to 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 transformation relationship between the base station coordinate system and the world coordinate system. The control component is used to receive coordinate information obtained by multiple photogrammetry components (1), and to perform intersection measurement based on the transformation relationship between the selected base station coordinate system and the coordinate system of each photogrammetry 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 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 to control the multiple rotating components (2) to drive the photogrammetry components (1) on them to rotate according to the relative angle, so that the shooting center of each photogrammetry component (1) is aligned with the point to be measured.

7. The measurement system according to claim 6, characterized in that, The control component includes an error compensation parameter module. The error compensation parameter includes a preset error compensation parameter. 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 parameter, the coordinate information of the reference point and the point to be measured in the base station coordinate system, and the transformation relationship between the base station coordinate system and the world coordinate system.

8. The measurement system according to claim 6, characterized in that, The rotating assembly (2) includes an upper turntable (20) and a lower turntable (21), both of which include a rotation output end; The central axis of the rotating output end of the upper turntable (20) is a horizontal axis. The photogrammetry component (1) is installed on the rotating output end of the upper turntable (20). The upper turntable (20) is used to drive the photogrammetry component (1) to rotate around the central axis of its rotating output end. The central axis of the rotation output end of the lower turntable (21) is a vertical axis. The upper turntable (20) is installed on the rotation output end of the lower turntable (21). The lower turntable (21) is used to drive the upper turntable (20) and the photogrammetry component (1) to rotate around the central axis of its rotation output end.

Images