Water-land integrated point cloud ranging system and calibration method

Abstract

This invention discloses a calibration method for an integrated land-water point cloud ranging system. The method involves calculating the standard coordinates of the center of the first and second target spheres based on prism coordinates, and then calculating the vertical distance between the centers of the first and second target spheres, denoted as the standard distance. The method also involves acquiring the detection coordinates of the center of the first and second target spheres, and calculating the vertical distance between them, denoted as the detection distance. The difference between the standard distance and the detection distance is calculated and output as a standard distance consistency evaluation value. Keeping the distance between the first target sphere and the horizontal plane constant, the method changes the distance between the second target sphere and the horizontal plane, returning to acquire the prism coordinates detected by the total station, until n standard distance consistency evaluation values ​​are obtained. The integrated land-water point cloud ranging system includes: a shipborne integrated land-water system, a point cloud ranging system, and a total station prism system.

Description

Technical Field

[0001] This invention relates to a shipborne integrated land and water measurement system, and more particularly to a calibration method for an integrated land and water point cloud ranging system. Background Technology

[0002] The shipborne integrated water-land measurement system, also known as the shipborne multi-sensor integrated surface and underwater measurement system, shipborne integrated mobile 3D measurement system, integrated water-shore measurement system, and shipborne integrated water-land point cloud ranging system, integrates multiple sensors such as a multibeam bathymetry system, a 3D laser scanner, positioning equipment, and attitude measurement equipment. It uses the multibeam bathymetry system to measure the water topography, the 3D laser scanner to measure the land topography, and the positioning and attitude measurement equipment to acquire position and attitude information. This enables synchronous, high-precision, and high-efficiency acquisition of near-shore surface and underwater topographic data. Compared with traditional techniques that separately acquire land and water data, this system can significantly reduce measurement blind spots and improve measurement accuracy and efficiency. It can provide important basic data support for transportation, port construction, safe navigation, estuary and coastal engineering development, water-land intermodal transport, and marine economy and marine resource development.

[0003] Currently, shipborne integrated land-water point cloud ranging systems with unified benchmarks and seamless synchronous data acquisition on land and water are cutting-edge equipment for engineering surveying and marine mapping research, and represent an inevitable trend for future development. Mature products are already in use both domestically and internationally in project production practices. The consistency and accuracy of the location of data acquired on and under the same benchmark are key indicators for evaluating the system. While there are existing metrological verification or calibration methods for some sensors—for example, for multibeam echo sounders, there is the draft for approval of the Ministry of Transport's Metrological Verification Regulation JJG (Transportation) "Calibration Specification for Shallow Water Multibeam Echo Sounders"; for 3D laser scanners, there is the National Metrological Technical Specification JJF 1406-2013 "Calibration Specification for Terrestrial Laser Scanners"; for satellite positioning equipment, there is the National Metrological Technical Specification JJF 1118-2004 "Calibration Specification for Global Positioning System (GPS) Receivers (Geometry and Navigation Types)"; and for attitude sensors, there is the Ministry of Transport's Metrological Verification Regulation JJG (Transportation) 170-2020 "Verification Regulation for Attitude Measurement Instruments in Water Transport Engineering"—these are all relevant to the current situation. These calibration specifications or procedures only calibrate or verify individual sensors, that is, evaluate the quality of data measured by each sensor. However, highly integrated shipborne integrated land-sea measurement systems are mainly affected by the accuracy of each sensor, installation errors, and the performance of the acquisition software. Often, the quality of sensor data cannot represent the quality of system data, making it difficult to detect the consistency of point clouds above and below water. There are currently no national, departmental, or local metrological verification or calibration specifications for the entire shipborne integrated land-sea measurement system, lacking corresponding evaluation criteria.

[0004] Existing detection methods only target individual sensors. However, shipborne integrated water-land point cloud ranging systems are primarily affected by the accuracy of individual sensors, installation errors, and the performance of the acquisition software. The quality of sensor data cannot replace the data quality of the integrated water-land point cloud ranging system, and there is currently no method to detect the entire system. Therefore, this study aims to develop a specific detection method for the consistency detection of surface and underwater point clouds in shipborne integrated water-land measurement systems, thereby providing assurance for the performance evaluation and data quality of these systems. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a calibration method for an integrated land and water point cloud ranging system that is simple to operate, highly integrated, portable, and highly practical.

[0006] The purpose of this invention is to provide an integrated land and water point cloud ranging system that is highly accurate and easy to assemble.

[0007] Technical Solution: To achieve the above-mentioned objective, a calibration method for an integrated land-water point cloud ranging system is provided, applied to an integrated land-water point cloud ranging device. The device includes a first target sphere above a horizontal plane, a second target sphere below the horizontal plane, a prism disposed on the surface of the first target sphere, and a telescopic rod connecting the first and second target spheres. The method includes:

[0008] S100: Obtain the coordinates of the prism detected by the total station;

[0009] S200: Calculate the standard coordinates of the center of the first target ball and the center of the second target ball based on the prism coordinates, and calculate the vertical distance between the center of the first target ball and the center of the second target ball, which is denoted as the standard distance.

[0010] S300: Obtain the detection coordinates of the center of the first target ball and the center of the second target ball, and calculate the vertical distance between the center of the first target ball and the center of the second target ball, which is denoted as the detection distance;

[0011] S400: Calculate the difference between the standard distance and the detection distance, and output it as the standard distance consistency assessment value;

[0012] S500: Keep the distance between the first target ball and the horizontal plane unchanged, change the distance between the second target ball and the horizontal plane, return to S100, until n standard distance consistency evaluation values ​​are obtained, where n is a positive integer greater than or equal to 4.

[0013] Preferably, before step S100, the method further includes: leveling the prism, the first target ball, and the second target ball to ensure that the centers of the prism, the first target ball, and the second target ball are on the same vertical line. The leveling operation includes, but is not limited to, a leveling device to ensure the acquisition of standard values ​​for the center position of the target ball and the distance between the centers of the two target balls, greatly simplifying the experimental difficulty and data processing algorithm; furthermore, regarding measurement accuracy, the combined use of the total station and the prism ensures the accuracy and reliability of the standard values.

[0014] In a preferred embodiment of the present invention, the prism is a triangular prism, and the total station is a 1mm+ppm high-precision total station.

[0015] Preferably, step S300 further includes: collecting the coordinates of the center of the first target ball and the center of the second target ball in a reciprocating motion; fitting the collected coordinates of the first and second target ball centers to obtain the detection coordinates of the center of the first and second target balls. Any distance value can be set on a horizontal plane between 10 and 50 meters from the telescopic pole for reciprocating motion and measurements at different distances, ensuring the accuracy and rigor of the experimental data.

[0016] Preferably, after step S300, the method further includes: calculating the coordinate difference between the standard coordinates of the center of the first target ball and the detection coordinates of the center of the first target ball, and outputting this coordinate difference as the consistency evaluation value of the first target ball, as shown in Formula 1.

[0017] p up (X up ,Y up Z up )-p upi (X upi ,Y upi Z upi ). Formula 1;

[0018] Calculate the coordinate difference between the standard coordinates of the center of the second target ball and the detection coordinates of the center of the second target ball. Output this coordinate difference as the consistency evaluation value of the second target ball, as shown in Formula 2.

[0019] P down (X down ,Y down Z down )-P downi (X downi ,Y downi Z downi ) Formula 2;

[0020] Where, p up (X up ,Y up Z up P represents the standard coordinates of the first target ball.down (X down ,Y down Z down ) represents the standard coordinates of the second target ball, p upi (X upi ,Y upi Z upi P represents the detection coordinates of the first target ball. downi (X downi ,Y downi Z downi () represents the detection coordinates of the second target ball.

[0021] Preferably, after S300, the method further includes: projecting the detection coordinates of the center of the first target ball and the detection coordinates of the center of the second target ball onto the same plane;

[0022] Calculate the planar difference between the coordinates of the center of the first target ball and the center of the second target ball projected onto the plane. Output this planar difference as the consistency evaluation value between the first and second target balls, as shown in Formula 3.

[0023]

[0024] Preferably, step S400 further includes: outputting the standard distance consistency assessment value calculated according to formula 4 as: Z upi -Z downi -S i Formula 4;

[0025] Among them, Z upi Z is the vertical axis of the first target ball's center detection coordinates. downi S is the vertical axis of the second target ball center detection coordinate. i It is the standard distance between the centers of the first and second target balls.

[0026] Preferably, step S500 further includes: averaging the first target ball consistency output evaluation value and then outputting it; as shown in Formula 5.

[0027]

[0028] The average of the consistency evaluation values ​​for the second target ball is then output, as shown in Formula 6.

[0029]

[0030] The average of the standard distance consistency evaluation values ​​is then output, as shown in Formula 7.

[0031]

[0032] The consistency evaluation values ​​of the first and second target balls are averaged and then output, as shown in Formula 8.

[0033]

[0034] Obtain comprehensive consistency test indicators for surface and underwater point clouds;

[0035] Where, p up (X up ,Y up Z up P represents the standard coordinates of the first target ball. down (X down ,Y down Z down ) represents the standard coordinates of the second target ball, p upi (X upi ,Y upi Z upi P represents the detection coordinates of the first target ball. downi (X downi ,Y downi Z downi ) represents the detection coordinates of the second target ball, i represents the sequence number corresponding to different distances of the second target ball from the horizontal plane, and n represents the number of water depth sequence numbers included.

[0036] Preferably, the telescopic rod can flexibly adjust the distance between the second target ball and the horizontal plane. The distance between the second target ball and the horizontal plane can be greater than 2 meters, which facilitates the collection and statistical analysis of underwater target ball point cloud data.

[0037] Preferably, the coordinates of the center of the first target sphere and the coordinates of the center of the second target sphere are obtained in the same coordinate system. The diameter of the target sphere can be greater than or equal to 0.5 meters to ensure that the surface and underwater point cloud measurement system can collect data from the target sphere.

[0038] The integrated land-water point cloud ranging system includes: a shipborne integrated land-water system, a point cloud ranging system, and a total station prism system;

[0039] The total station prism system is used to detect the standard coordinates and standard distance between the center of the first target sphere and the center of the second target sphere in the integrated land-water point cloud ranging system.

[0040] The point cloud ranging system is used to verify the indication error of the detection coordinates and detection distance of the center of the first and second target spheres in the shipborne integrated water and land system.

[0041] Beneficial effects: The geometric center of the spherical target is equidistant from all points on the surface of the sphere, and point cloud data of half of its surface can be obtained from any angle during data acquisition, making it easier to fit its geometric center; the leveling operation ensures that the centers of the first target sphere, the second target sphere, and the prism center are on the same vertical line, greatly simplifying the experimental difficulty and experimental data processing algorithm; the use of the shipborne integrated water and land measurement system for round trips and measurements at different distances ensures the accuracy and rigor of the experimental data.

[0042] This testing method can accurately and effectively assess the consistency of surface and underwater point clouds detected by a shipborne integrated land-sea measurement system. It ensures the accuracy and reliability of production data, boosting operator confidence. Furthermore, the method is simple to operate, highly integrated, and portable, enabling the reproduction of identical results in different locations. This reduces the technical requirements for technicians, and the measurement equipment is easy to maintain, laying the foundation for future upgrades and modifications. Its high practicality significantly reduces costs. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the integrated land and water point cloud ranging device in Example 1;

[0044] Figure 2 This is a schematic diagram of point cloud ranging for integrated land and water measurement in Example 1. Detailed Implementation

[0045] Example 1

[0046] like Figure 1 As shown, a calibration method for an integrated land-water point cloud ranging system is applied to an integrated land-water point cloud ranging device. The device includes a first target sphere 2 located above the horizontal plane, a second target sphere 5 located below the horizontal plane, a prism 1 disposed on the surface of the first target sphere 2, and a telescopic rod 4 connecting the first target sphere 2 and the second target sphere 5. The method includes:

[0047] The leveling device 3 is used to make the centers of the triangular prism 1, the first target ball 2, and the second target ball 5 lie on the same vertical line.

[0048] The distance between the first target ball 2 and the horizontal plane is set to be 2m and kept constant. The distance between the second target ball 5 and the horizontal plane is adjusted to 2m, 4m, 6m and 8m respectively by adjusting the length of the telescopic rod. The corresponding numbers are i=1, 2, 3 and 4 respectively. The coordinates of the prism 1 are obtained by the high-precision total station with 1mm+ppm.

[0049] Calculate the standard coordinates of the center of the first target ball 2 and the center of the second target ball 5 based on the coordinates of prism 1, and calculate the vertical distance between the center of the first target ball 2 and the center of the second target ball 5, which is denoted as the standard distance.

[0050] like Figure 2 As shown, at distances of 10m, 20m, and 30m from the telescopic pole, the coordinates of the center of the first target ball 2 and the center of the second target ball 5 are collected in a round trip. The collected coordinates of the center of the first target ball 2 and the center of the second target ball 5 are fitted to obtain the detection coordinates of the center of the first target ball 2 and the center of the second target ball 5. The vertical distance between the center of the first target ball 2 and the center of the second target ball 5 is calculated and recorded as the detection distance.

[0051] The coordinates of the center of the first target ball 2 and the center of the second target ball 5 were obtained in the same coordinate system.

[0052] Calculate the coordinate difference between the standard coordinates and the detected coordinates of the center of the first target ball 2 according to Formula 1, and output this coordinate difference as the consistency evaluation value of the first target ball 2.

[0053] p up (X up ,Y up Z up )-p upi (X upi ,Y upi Z upi ). Formula 1;

[0054] Calculate the coordinate difference between the standard coordinates of the center of the second target ball 5 and the detected coordinates of the center of the second target ball 5 according to Formula 2, and output this coordinate difference as the consistency evaluation value of the second target ball 5.

[0055] P down (X down ,Y down Z down )-P downi (X downi ,Y downi Z downi ) Formula 2;

[0056] Project the detection coordinates of the center of the first target ball 2 and the detection coordinates of the center of the second target ball 5 onto the same plane;

[0057] Calculate the plane difference between the center coordinates of the first target sphere 2 and the center coordinates of the second target sphere 5 projected onto the plane according to Formula 3. Output this plane difference as the consistency evaluation value between the first target sphere 2 and the second target sphere 5.

[0058]

[0059] The difference between the standard distance and the detection distance is calculated according to Formula 4, and the consistency evaluation value of the standard distance is output as follows:

[0060] Z upi -Z downi -Si Formula 4;

[0061] The consistency evaluation value of the first target ball 2 is averaged according to Formula 5 and then output.

[0062]

[0063] The consistency evaluation value of the second target ball 5 is averaged and then output according to Formula 6.

[0064]

[0065] The standard distance consistency evaluation values ​​are averaged according to Formula 7 and then output.

[0066]

[0067] The consistency evaluation values ​​of the first target ball 2 and the second target ball 5 are averaged according to Formula 8 and then output.

[0068]

[0069] Obtain comprehensive consistency test indicators for surface and underwater point clouds;

[0070] Where, p up (X up ,Y up Z up P represents the standard coordinates of the first target ball 2. down (X down ,Y down Z down ) represents the standard coordinates of the second target ball 5, p upi (X upi ,Y upi Z upi P represents the detection coordinates of the first target ball 2. downi (X downi ,Y downi Z downi S represents the detection coordinates of the second target ball 5. i It is the standard distance between the centers of the first target ball 2 and the second target ball 5, i represents the sequence number corresponding to different distances of the second target ball 5 from the horizontal plane, and n is 4.

[0071] The integrated land-water point cloud ranging system includes: a shipborne integrated land-water system, a point cloud ranging system, and a total station prism system;

[0072] The total station prism system is used to detect the standard coordinates and standard distance between the center of the first target sphere 2 and the center of the second target sphere 5 in the point cloud ranging system;

[0073] The point cloud ranging system is used to verify the indication error of the detection coordinates and detection distance of the center of the first target sphere 2 and the center of the second target sphere 5 in the shipborne integrated water and land system.

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A calibration method for an integrated land-water point cloud ranging system, characterized in that, An integrated point cloud ranging device for land and water applications is provided. The device includes a first target sphere above a horizontal plane, a second target sphere below the horizontal plane, a prism disposed on the surface of the first target sphere, and a telescopic rod connecting the first and second target spheres. The method includes: S100: Obtain the coordinates of the prism detected by the total station; S200: Calculate the standard coordinates of the center of the first target ball and the center of the second target ball based on the prism coordinates, and calculate the vertical distance between the center of the first target ball and the center of the second target ball, which is denoted as the standard distance. S300: Obtain the detection coordinates of the center of the first target ball and the center of the second target ball, and calculate the vertical distance between the center of the first target ball and the center of the second target ball, which is denoted as the detection distance; S400: Calculate the difference between the standard distance and the detection distance, and output it as the standard distance consistency assessment value; S500: Keep the distance between the first target ball and the horizontal plane constant, change the distance between the second target ball and the horizontal plane, return to S100, until n standard distance consistency evaluation values ​​are obtained, where n is a positive integer greater than or equal to 4; The S500 also includes: The average of the consistency evaluation values ​​of the first target ball is then output according to Formula 5. Official 5; The average of the second target ball consistency evaluation values ​​is then output according to Formula 6. Official 6; The standard distance consistency evaluation values ​​are averaged according to Formula 7 and then output. Official 7; The consistency evaluation values ​​of the first and second target balls are averaged according to Formula 8 and then output. Official 8; Obtain comprehensive consistency test indicators for surface and underwater point clouds; in, The standard coordinates of the first target ball, The standard coordinates of the second target ball. The detection coordinates of the first target ball are given. Let i represent the detection coordinates of the second target ball, i represent the sequence number corresponding to different distances of the second target ball from the horizontal plane, and n represent the number of water depth sequence numbers included.

2. The calibration method for the integrated land-water point cloud ranging system according to claim 1, characterized in that, Before S100, it also includes: The prism, the first target ball, and the second target ball are leveled so that the centers of the prism, the first target ball, and the second target ball are on the same vertical line.

3. The calibration method for the integrated land-water point cloud ranging system according to claim 1, characterized in that, The S300 also includes: The coordinates of the center of the first target ball and the center of the second target ball are collected in a round trip. The collected coordinates of the first target ball and the center of the second target ball are fitted to obtain the detection coordinates of the center of the first target ball and the detection coordinates of the center of the second target ball.

4. The calibration method for the integrated land-water point cloud ranging system according to claim 1, characterized in that, Following S300, the following is also included: Calculate the coordinate difference between the standard coordinates and the detection coordinates of the center of the first target ball according to Formula 1, and output this coordinate difference as the consistency evaluation value of the first target ball. Official 1; Calculate the coordinate difference between the standard coordinates of the second target ball's center and the detection coordinates of the second target ball's center according to Formula 2, and output this coordinate difference as the consistency evaluation value of the second target ball. Official 2; in, The standard coordinates of the first target ball, The standard coordinates of the second target ball. The detection coordinates of the first target ball are given. The coordinates for detecting the second target ball are given.

5. The calibration method for the integrated land-water point cloud ranging system according to claim 4, characterized in that, Following S300, the following is also included: Project the detection coordinates of the center of the first target ball and the detection coordinates of the center of the second target ball onto the same plane; Calculate the planar difference between the center coordinates of the first target ball and the center coordinates of the second target ball projected onto the plane using Formula 3. Output this planar difference as the consistency evaluation value between the first and second target balls. Formula 3; 6. The calibration method for the integrated land-water point cloud ranging system according to claim 1, characterized in that, The S400 also includes: The standard distance consistency assessment value calculated according to Formula 4 is output as follows: Formula 4; in, It is the vertical axis of the coordinate system for detecting the center of the first target ball. It is the vertical axis of the coordinate system for detecting the center of the second target ball. It is the standard distance between the centers of the first and second target balls.

7. The calibration method for the integrated land-water point cloud ranging system according to claim 1, characterized in that, The telescopic rod can flexibly adjust the distance between the second target ball and the horizontal plane.

8. The calibration method for the integrated land-water point cloud ranging system according to claim 3, characterized in that, The coordinates of the center of the first target ball and the coordinates of the center of the second target ball are obtained in the same coordinate system.

9. A water-land integrated point cloud ranging system, characterized in that, The method of calibration for the integrated land-water point cloud ranging system as described in any one of claims 1-8 is also included: a shipborne integrated land-water system, a point cloud ranging system, and a total station prism system. The total station prism system is used to detect the standard coordinates and standard distance between the center of the first target sphere and the center of the second target sphere in the point cloud ranging system. The point cloud ranging system is used to verify the indication error of the detection coordinates and detection distance of the center of the first and second target spheres in the shipborne integrated water and land system.

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