A ship hatch data management method based on point cloud technology

Abstract

The present invention is a method for managing ship hatch data based on point cloud technology. This method is implemented through a constructed ship hatch data management system, which includes a ship scanning module, an automatic hatch identification and calculation module, a ship attitude data compensation module, and a hatch data calibration and accumulation module. By processing scanner data and analyzing point cloud data, combined with the ship loader's mechanical parameters, the method generates a point cloud model of the ship to be operated. The method then automatically identifies the ship's hatch position and calculates the hatch's spatial coordinates within the dock's rectangular coordinate system. The method then calibrates the hatch identification data for the current berthing based on hatch data records from previous berthings with the same hull number in a database. The calculated hatch position guides the ship loader to achieve both unmanned and automated operation modes, enhancing the port's automation level.

Description

Technical Field

[0001] The present invention relates to the technical field of ship loader operation control automation transformation engineering, and in particular to a ship hatch data management method based on point cloud technology. Background Art

[0002] While automated ship loading technology has already gained considerable market traction, it still faces significant limitations, such as limited support for fixed ship types and simple operating modes and conditions. These factors hinder the development of fully automated and highly adaptable intelligent ship loading technology. Consequently, ship loaders are still largely controlled manually, and the safety and efficiency of production operations depend entirely on the operator's proficiency and focus. This labor-intensive operation, coupled with the reliance on manual labor, hinders operational efficiency and safety.

[0003] For example, Chinese utility model patent publication number CN213211045U discloses a ship hatch identification system for a ship loader. This system primarily aims to reduce the likelihood of collisions and increase safety during operation through installed hardware devices, but its hatch identification accuracy is generally average. Summary of the Invention

[0004] The present invention aims to solve the problems of large limitations of automatic loading technology in the existing technology, such as only supporting fixed ship types, only supporting simple operation modes and working conditions, limited development of fully automated and highly adaptable intelligent loading technology, and poor hatch recognition accuracy in the field of ship automation operations, and provides a ship hatch data management method based on point cloud technology.

[0005] To achieve the above-mentioned object, the present invention adopts the following technical solutions: a ship hatch data management method based on point cloud technology, which is realized by constructing a ship hatch data management system, which includes a ship scanning module, a hatch automatic identification and calculation module, a ship attitude data compensation module, and a hatch data calibration and accumulation module;

[0006] The system includes the following steps when used:

[0007] S1. The ship scanning module processes the collected data and analyzes the point cloud data, and calculates and generates a point cloud model of the ship to be operated based on the ship loader's structural parameters;

[0008] S1 includes the following steps:

[0009] S11, parsing the raw data collected by the scanner into point data;

[0010] S12. Perform mathematical processing on the point data returned by the scanner. The single-point mathematical processing method is as follows:

[0011] S121. Calculate the current scanning area: the angle θ between the scanning point and the scanner perpendicular to the ground, and the vertical height h of the scanner from the plane with the z-axis coordinate of 0, where h = h1 + h2, where h1 is the vertical height of the scanning point from the scanner, and h2 is the vertical height of the scanning point from the plane with the z-axis coordinate of 0;

[0012] S122. Obtain the straight-line distance l between the scanning point and the scanner, construct a mathematical model, construct a trigonometric function from h, l, and θ, calculate the length d of the opposite side of the trigonometric function, where d is the y value of the scanning point in the rectangular coordinate system, construct a triangle with sides d, l, and angle θ, and calculate the lengths h1 and h2 of the adjacent sides, where h2 is the z value of the scanning point in the rectangular coordinate system. That is, the coordinates of a single scanning point after rectangular coordinate system conversion are (d, h2);

[0013] S13. Scan the sector area with the scanner once, and form linear point cloud coordinates through superposition and positioning of data. The implementation method is as follows:

[0014] S131, performing rectangular coordinate conversion processing on all points returned by a single scan by the scanner to form (y, z) coordinates of all points in the current area;

[0015] S132. Obtain the large machine travel data from the PLC, use the large machine travel data as the x-axis coordinate to complete the spatial rectangular coordinate system with the rotation center as the origin, calculate the (x, y, z) coordinates of all scanning points under the current x-axis coordinate, and generate a two-dimensional point cloud set;

[0016] S14. Compensate all point coordinates by:

[0017] S141. Based on the rotation angle and pitch angle values ​​of the aircraft, perform trigonometric processing on the coordinate values ​​of all points to ensure that the data are in the same plane.

[0018] S142. Compare the rotation angle with the case of 0 degrees, construct a right triangle using the rotation angle and the y value, and calculate the lengths of the opposite side and the adjacent side. The adjacent side length is the actual y-coordinate y1 of the point, and the x-coordinate minus the opposite side length is the actual x-coordinate x1. The same is true for pitch. Process and convert the data of all points to obtain the coordinates (x1, y1, z).

[0019] S15. Monitor the changes in the machine's travel data in real time. When the machine starts the scanning program and the travel encoder changes, the linear two-dimensional point cloud set generation operation is repeated according to the cycle and change frequency. The two-dimensional point cloud sets obtained multiple times are spliced ​​and overwritten to generate a point cloud model and coordinate file, which is the original point cloud file.

[0020] S2, the hatch automatic identification and calculation module analyzes and processes the original point cloud file according to the automatic identification algorithm, and calculates the hatch position and the spatial coordinates of the hatch in the dock space rectangular coordinate system;

[0021] S3, the ship attitude data compensation module compensates for the change in ship attitude caused by tide and load factors during the cabin change process of the ship loader and updates the hatch coordinates;

[0022] S4. Download the calculated hatch position coordinate information to the ship loader PLC to guide the ship loader to achieve unmanned and automated operation, thereby enhancing the port's automation level;

[0023] S5. After the loading operation is completed, the hatch data calibration and accumulation module stores the results of the ship point cloud data analysis and the ship operation information in the database. The next time the ship with the same hull number docks for operation, it is used to perform a second calibration of the scanned hatch data to determine whether the scanning and data analysis programs are running normally. At the same time, the data can be provided to the central control or other operation production management platforms for integration and unified display.

[0024] Specifically, S2 includes the following steps:

[0025] S21. Analyze and process the original point cloud file and calculate the maximum y-value of the ship, y1'. The system reads the y-value constant y2 of the dock side and the width of the crash barrier, w1, by default. The ship width is determined based on the values ​​of y2 and y1'. The average value is taken to obtain the y-value of the center of the ship. The point cloud is divided into blocks according to the center line of the y-value. The height change along the center line is compared to determine the approximate location of the ship hatch.

[0026] S22. Obtain the coordinates of two random points at the upper left and lower right locations inside the hatch. Decrease the x value of the upper left point to x1' and increase its y value to y1''. Increase the x value of the lower right point to x2 and decrease its y value to y2'. During the movement, query the first point whose coordinate variables have actual coordinates. Continue to diffuse this point in the direction of change by a certain range n. Calculate the average y value y3 of all points whose x coordinates are within the range x1'+n. y3-n\2 is the boundary value y4 of the hatch in the direction of decreasing x values. Use the same method to calculate x4, y5, and x5 of the remaining three boundary lines to obtain the coordinates of the four vertices.

[0027] S23. Compare the elevation coordinates of all points from x to x1'+n, sort them from high to low, take the highest k points and calculate the average z value, which is the edge height. After obtaining the heights of the four edges, compare the sea and land sides, and the front and back sides, and take the two maximum values ​​to obtain z1 and z2. Compare z1 and z2. The higher value is the hatch height, and the lower value is the hatch height. In this way, the coordinate values ​​of the four sides and four corners of all hatches are obtained, and the hatch coordinates and hatch cover height are determined.

[0028] Specifically, S3 includes the following steps:

[0029] S31. Monitor the cabin change signal, the large engine travel, rotation, and pitch encoders. When the cabin change signal is triggered, the ship scanning program is started after the encoder data of each mechanism is updated and reset, and a point cloud file of the ship segment during the cabin change process is generated. A point cloud model of the ship segment is constructed in the same manner as the overall ship scanning modeling, and the elevation feature values ​​are selected and compared with the ship's inclination and roll parameters.

[0030] S32. Compare the point cloud files of the two scans, calculate the hatch feature points of the scannable cabin, compare the coordinate changes of the hatches with the same cabin number in the two scan files, calculate the changes in the inclination and roll values ​​of the hull during the loading process based on the coordinate changes of the two scan results, and then infer the changes in the angle and height of the entire ship through the changes, update the ship model as a whole, and thus update the hatch coordinate data in the PLC.

[0031] The beneficial effects of the present invention are:

[0032] 1. The present invention processes scanner data and analyzes point cloud data, combining it with the ship loader's mechanical parameters to generate a point cloud model of the ship to be operated, automatically identifies the ship's hatch position, and automatically calculates the spatial coordinates of the ship's hatch in the rectangular coordinate system of the dock space. The hatch identification data for this berthing is calibrated based on the hatch data records of previous berthings with the same hull number in the database. The calculated hatch position guides the ship loader to achieve unmanned and automated operation modes, enhancing the port's automation level. The loading operation does not rely on manual labor, and the operation efficiency and operational safety can be well guaranteed. Compared with the existing technology, the present invention mainly processes and calculates the ship's point cloud data before and during the operation, assists the ship loader in positioning the operation point, and reduces the impact of the on-site environment on the operation.

[0033] 2. After the ship docks at the wharf, the present invention generates point cloud data by performing walking scanning by the ship loader. Based on the point cloud data, the position and spatial coordinates of the ship's hatches are automatically identified and calculated, and the coordinates of the four corners of each hatch and the heights of the hatch cover, hatch and hold bottom in the same coordinate system of the wharf-ship loader-ship are obtained. The scanning modeling and data update algorithm during the ship loader's cabin change process compensates for the changes in the ship's posture caused by factors such as tides and loading volume during the operation, providing and implementing a more efficient and safer ship loader control strategy. The loading operation does not require manual control, the hatch position is accurately judged, collisions are avoided during movement, and unmanned automation progresses quickly.

[0034] 3. The present invention realizes the problem of automatic calculation and automatic update of ship hatch position based on point cloud technology, solves the problem of hatch automatic identification in the field of ship automation operation and the problem of inability to calculate the change value of ship posture (elevation, inclination and roll) caused by tide and load through normal methods during cargo loading operations at the terminal. The use of the present invention can realize automatic identification of hatches and automatic update of hatch data at most terminals and most ships. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a module diagram of the ship hatch data management system of the present invention;

[0036] Figure 2 Schematic diagram of ship scanning point cloud data conversion in S1 of the present invention;

[0037] Figure 3 The ship point cloud model diagram generated in S1 of the present invention;

[0038] Figure 4 The point cloud image of hatch identification and feature point selection in S2 of the present invention;

[0039] Figure 5 A point cloud diagram showing changes in the ship's loading capacity generated during the ship loader's cabin-changing operation in S3 of the present invention;

[0040] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with embodiment:

[0042] like Figure 1 As shown, a ship hatch data management method based on point cloud technology is implemented by constructing a ship hatch data management system, which includes a ship scanning module, a hatch automatic recognition and calculation module, a ship attitude data compensation module, and a hatch data calibration and accumulation module;

[0043] Among them, the scanner used in the ship hatch scanning module is a laser scanner.

[0044] The system includes the following steps when used:

[0045] S1, such as Figure 2 、 Figure 3 As shown, the ship scanning module processes the collected data and analyzes the point cloud data, and calculates and generates a point cloud model of the ship to be operated in combination with the ship loader's structural parameters;

[0046] S1 includes the following steps:

[0047] S11. Parse the raw data collected by the scanner into point data. Specifically, the data returned by the laser scanner via a message is a long string containing a large amount of configuration data, such as the scanner's scanning cycle, angle, current status, etc. After splitting, decoding, and conversion, the point data returned by the current scanner is obtained. These point data are all angular vector coordinates, including the straight-line distance of the scanned point, the scanning angle, etc.

[0048] S12. Perform mathematical processing on the point data returned by the scanner. To achieve unified coordinate system management of the yard, each returned point needs to be divided and converted into a rectangular coordinate system. The mathematical processing method for a single point is as follows:

[0049] S121. Calculate the current scanning area: the angle θ between the scanning point and the scanner perpendicular to the ground, and the vertical height h of the scanner from the plane with the z-axis coordinate of 0, where h = h1 + h2, where h1 is the vertical height of the scanning point from the scanner, and h2 is the vertical height of the scanning point from the plane with the z-axis coordinate of 0;

[0050] S122. Obtain the straight-line distance l between the scanning point and the scanner, construct a mathematical model, construct a trigonometric function from h, l, and θ, calculate the length d of the opposite side of the trigonometric function, where d is the y value of the scanning point in the rectangular coordinate system, construct a triangle with sides d, l, and angle θ, and calculate the lengths h1 and h2 of the adjacent sides, where h2 is the z value of the scanning point in the rectangular coordinate system. That is, the coordinates of a single scanning point after rectangular coordinate system conversion are (d, h2);

[0051] S13. Scan the sector area with the scanner once, and form linear point cloud coordinates through superposition and positioning of data. The implementation method is as follows:

[0052] S131, performing rectangular coordinate conversion processing on all points returned by a single scan by the scanner to form (y, z) coordinates of all points in the current area;

[0053] S132. Obtain the large machine travel data from the PLC, use the large machine travel data as the x-axis coordinate to complete the spatial rectangular coordinate system with the rotation center as the origin, calculate the (x, y, z) coordinates of all scanning points under the current x-axis coordinate, and generate a two-dimensional point cloud set;

[0054] S14. Due to the mechanism problem, it is impossible to accurately restore to 0 position. There will be some deviation. Therefore, it is necessary to compensate the coordinates of all points. The implementation method is as follows:

[0055] S141. Based on the rotation angle and pitch angle values ​​of the aircraft, perform trigonometric processing on the coordinate values ​​of all points to ensure that the data are in the same plane.

[0056] S142. Compare the rotation angle with the case of 0 degrees, construct a right triangle using the rotation angle and the y value, and calculate the lengths of the opposite side and the adjacent side. The adjacent side length is the actual y-coordinate y1 of the point, and the x-coordinate minus the opposite side length is the actual x-coordinate x1. The same is true for pitch. Process and convert the data of all points to obtain the coordinates (x1, y1, z).

[0057] S15, real-time monitoring of the machine's walking data changes, when the machine starts the scanning program, after the walking encoder changes, repeat the linear two-dimensional point cloud set generation operation according to the cycle and change frequency, splice and overwrite the two-dimensional point cloud sets obtained multiple times, generate a point cloud model and coordinate file, which is the original point cloud file, such as Figure 3 shown.

[0058] S2, such as Figure 4 As shown, the hatch automatic recognition and calculation module analyzes and processes the original point cloud file according to the automatic recognition algorithm, and calculates the hatch position and the spatial coordinates of the hatch in the dock space rectangular coordinate system;

[0059] S2 includes the following steps:

[0060] S21. Analyze and process the original point cloud file and calculate the maximum y-value of the ship, y1' (furthest from the dock). The system defaults to reading the y-value constant y2 at the dock and the width of the crash barrier w1. The ship width is determined based on the values ​​of y2 and y1'. The average value is taken to obtain the y-value of the center of the ship. The point cloud is divided into blocks according to the center line of this y-value. The height change along the center line is compared to determine the approximate location of the ship hatch.

[0061] S22. Obtain the coordinates of two random points at the upper left and lower right locations inside the hatch. Decrease the x value of the upper left point to x1' and increase its y value to y1''. Increase the x value of the lower right point to x2 and decrease its y value to y2'. During the movement, query the first point whose coordinate variables have actual coordinates. Continue to diffuse this point in the direction of change by a certain range n. Calculate the average y value y3 of all points whose x coordinates are within the range x1'+n. y3-n\2 is the boundary value y4 of the hatch in the direction of decreasing x values. Use the same method to calculate x4, y5, and x5 of the remaining three boundary lines to obtain the coordinates of the four vertices.

[0062] S23. Compare the elevation coordinates of all points from x to x1'+n, sort them from high to low, take the highest k points and calculate the average z value, which is the edge height. After obtaining the heights of the four edges, compare the sea and land sides, and the front and back sides, and take the two maximum values ​​to obtain z1 and z2. Compare z1 and z2. The higher value is the hatch height, and the lower value is the hatch height. In this way, the coordinate values ​​of the four sides and four corners of all hatches are obtained, and the hatch coordinates and hatch cover height are determined.

[0063] S3, such as Figure 5As shown, the ship attitude data compensation module compensates for the change in ship attitude caused by tide and load factors during the cabin change process of the loader and updates the hatch coordinates;

[0064] Through the ship loader movement logic and scanner control logic, during the ship loader operation and cabin change process, the ship point cloud data of this stage is generated. The original point cloud data is compared with the cabin change point cloud data. The valid data is selected based on the feature points. The roll and pitch offset changes caused by the current ship posture compared with the original posture are calculated. The coordinates of all ship hatches are updated and the data of the ship posture detection system based on Beidou positioning is compensated.

[0065] S3 includes the following steps:

[0066] S31. Monitor the cabin change signal, the large engine travel, rotation, and pitch encoders. When the cabin change signal is triggered, the ship scanning program is started after the encoder data of each mechanism is updated and reset, and a point cloud file of the ship segment during the cabin change process is generated. A point cloud model of the ship segment is constructed in the same manner as the overall ship scanning modeling, and the elevation feature values ​​are selected and compared with the ship's inclination and roll parameters.

[0067] S32. Compare the point cloud files of the two scans, calculate the hatch feature points of the scannable cabin, compare the coordinate changes of the hatches with the same cabin number in the two scan files, calculate the changes in the inclination and roll values ​​of the hull during the loading process based on the coordinate changes of the two scan results, and then infer the changes in the angle and height of the entire ship through the changes, update the ship model as a whole, and thus update the hatch coordinate data in the PLC.

[0068] S4. Download the calculated hatch position coordinate information to the ship loader PLC to guide the ship loader to achieve unmanned and automated operation, thereby enhancing the port's automation level;

[0069] S5. After the loading operation is completed, the hatch data calibration and accumulation module stores the results of the ship point cloud data analysis and the ship operation information in the database. The next time the ship with the same hull number docks for operation, it is used to perform a second calibration of the scanned hatch data to determine whether the scanning and data analysis programs are running normally. At the same time, the data can be provided to the central control or other operation production management platforms for integration and unified display.

[0070] The present invention is more comprehensive and reliable in technology from scanning data processing to spatial coordinate compensation, reduces errors, and adopts block division to calculate the hatch boundary coordinates and height interval from the inside to the outside along the central axis, and calculates the final data using the expected algorithm.

[0071] Given the diverse types, models, and specifications of berthing vessels, the complex mechanisms of ship loaders, and the numerous operating modes, coupled with the lack of comprehensive terminal hardware infrastructure, the ship hatch data management system proposed in this paper requires compatibility considerations and upgrades. This system supports multi-type ship hatch data analysis, automated operation safety enhancements, and data aggregation and organization. This system enables hatch identification, scanning, and data management for different ships through the establishment of distinct models, providing data support and effective safety protection for ship loaders.

[0072] This invention processes laser scanner data and analyzes point cloud data, combining it with the ship loader's mechanical parameters to generate a point cloud model of the vessel being operated. It then automatically identifies the location of the ship's hatches and calculates their spatial coordinates within the dock's rectangular coordinate system. The calculated hatch positions guide the ship loader to achieve unmanned, automated operation, enhancing the port's automation level. This invention provides a more efficient and safer ship loader control strategy, fully adapting to the trend toward unmanned, information-based, and intelligent port bulk cargo loading equipment, and improving the company's core competitiveness.

[0073] The above is an exemplary description of the present invention. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or they are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A ship hatch data management method based on point cloud technology, implemented by constructing a ship hatch data management system, characterized in that: The system includes a ship scanning module, a hatch automatic identification and calculation module, a ship attitude data compensation module, and a hatch data calibration and accumulation module; The system includes the following steps when used: S1. The ship scanning module processes the collected data and analyzes the point cloud data, and calculates and generates a point cloud model of the ship to be operated based on the structural parameters of the ship loader; the steps include: S11, parsing the raw data collected by the scanner into point data; S12. Perform mathematical processing on the point data returned by the scanner. The single-point mathematical processing method is as follows: S121. Calculate the current scanning area: the angle θ between the scanning point and the scanner perpendicular to the ground, and the vertical height h of the scanner from the plane with the z-axis coordinate of 0, where h = h1 + h2, where h1 is the vertical height of the scanning point from the scanner, and h2 is the vertical height of the scanning point from the plane with the z-axis coordinate of 0; S122. Obtain the straight-line distance l between the scanning point and the scanner, construct a mathematical model, construct a trigonometric function from h, l, and θ, calculate the length d of the opposite side of the trigonometric function, where d is the y value of the scanning point in the rectangular coordinate system, construct a triangle with sides d, l, and angle θ, and calculate the lengths h1 and h2 of the adjacent sides, where h2 is the z value of the scanning point in the rectangular coordinate system. That is, the coordinates of a single scanning point after rectangular coordinate system conversion are (d, h2); S13. Scan the sector area with the scanner once, and form linear point cloud coordinates through superposition and positioning of data. The implementation method is as follows: S131, performing rectangular coordinate conversion processing on all points returned by a single scan by the scanner to form (y, z) coordinates of all points in the current area; S132. Obtain the large machine travel data from the PLC, use the large machine travel data as the x-axis coordinate to complete the spatial rectangular coordinate system with the rotation center as the origin, calculate the (x, y, z) coordinates of all scanning points under the current x-axis coordinate, and generate a two-dimensional point cloud set; S14. Compensate all point coordinates by: S141. Based on the rotation angle and pitch angle values ​​of the aircraft, perform trigonometric processing on the coordinate values ​​of all points to ensure that the data are in the same plane. S142. Compare the rotation angle with the case of 0 degrees, construct a right triangle using the rotation angle and the y value, and calculate the lengths of the opposite side and the adjacent side. The adjacent side length is the actual y-coordinate y1 of the point, and the x-coordinate minus the opposite side length is the actual x-coordinate x1. The same is true for pitch. Process and convert the data of all points to obtain the coordinates (x1, y1, z). S15. Monitor the changes in the machine's travel data in real time. When the machine starts the scanning program and the travel encoder changes, the linear two-dimensional point cloud set generation operation is repeated according to the cycle and change frequency. The two-dimensional point cloud sets obtained multiple times are spliced ​​and overwritten to generate a point cloud model and coordinate file, which is the original point cloud file. S2, hatch automatic identification and calculation module, analyzes and processes the original point cloud file according to the automatic identification algorithm, and calculates the hatch position and the spatial coordinates of the hatch in the dock space rectangular coordinate system; S3, the ship attitude data compensation module compensates for the change in ship attitude caused by tide and load factors during the cabin change process of the loader and updates the hatch coordinates; S4. Download the calculated hatch position coordinate information to the ship loader PLC to guide the ship loader to achieve unmanned and automated operation, thereby enhancing the port's automation level; S5. After the loading operation is completed, the hatch data calibration and accumulation module stores the results of the ship point cloud data analysis and the ship operation information in the database. The next time the ship with the same hull number docks for operation, it is used to perform a second calibration of the scanned hatch data to determine whether the scanning and data analysis programs are running normally. At the same time, the data can be provided to the central control or other operation production management platforms for integration and unified display.

2. The method for ship hatch data management based on point cloud technology according to claim 1, characterized in that: S2 includes the following steps: S21. Analyze and process the original point cloud file and calculate the maximum y-value of the ship, y1'. The system reads the y-value constant y2 of the dock side and the width of the crash barrier, w1, by default. The ship width is determined based on the values ​​of y2 and y1'. The average value is taken to obtain the y-value of the center of the ship. The point cloud is divided into blocks according to the center line of the y-value. The height change along the center line is compared to determine the approximate location of the ship hatch. S22. Obtain the coordinates of two random points at the upper left and lower right locations inside the hatch. Decrease the x value of the upper left point to x1' and increase its y value to y1''. Increase the x value of the lower right point to x2 and decrease its y value to y2'. During the movement, query the first point whose coordinate variables have actual coordinates. Continue to diffuse this point in the direction of change by a certain range n. Calculate the average y value y3 of all points whose x coordinates are within the range x1'+n. y3-n\2 is the boundary value y4 of the hatch in the direction of decreasing x values. Use the same method to calculate x4, y5, and x5 of the remaining three boundary lines to obtain the coordinates of the four vertices. S23. Compare the elevation coordinates of all points from x to x1'+n, sort them from high to low, take the highest k points and calculate the average z value, which is the edge height. After obtaining the heights of the four edges, compare the sea and land sides, and the front and back sides, and take the two maximum values ​​to obtain z1 and z2. Compare z1 and z2. The higher value is the hatch height, and the lower value is the hatch height. In this way, the coordinate values ​​of the four sides and four corners of all hatches are obtained, and the hatch coordinates and hatch cover height are determined.

3. The method for ship hatch data management based on point cloud technology according to claim 2, characterized in that: S3 includes the following steps: S31. Monitor the cabin change signal, the large engine travel, rotation, and pitch encoders. When the cabin change signal is triggered, the ship scanning program is started after the encoder data of each mechanism is updated and reset, and a point cloud file of the ship segment during the cabin change process is generated. A point cloud model of the ship segment is constructed in the same manner as the overall ship scanning modeling, and the elevation feature values ​​are selected and compared with the ship's inclination and roll parameters. S32. Compare the point cloud files of the two scans, calculate the hatch feature points of the scannable cabin, compare the coordinate changes of the hatches with the same cabin number in the two scan files, calculate the changes in the inclination and roll values ​​of the hull during the loading process based on the coordinate changes of the two scan results, and then infer the changes in the angle and height of the entire ship through the changes, update the ship model as a whole, and thus update the hatch coordinate data in the PLC.

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