Ship hatch data management method based on point cloud technology

Abstract

Provided in the present invention is a ship hatch data management method based on point cloud technology. The method is implemented by means of a constructed ship hatch data management system, and the system comprises 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. In the present invention, by means of processing data of a scanner and analyzing point cloud data, a point cloud model of a ship to be subjected to operation is generated in combination with mechanism parameters of a ship loader, the position of a ship hatch is automatically identified, the spatial coordinates of the ship hatch in a rectangular coordinate system of wharf space are automatically calculated, hatch identification data for current berthing is calibrated on the basis of historical hatch data records from the same hull number after berthing in a database, and the ship loader is guided to realize unmanned and automated operation modes by means of the calculated hatch position, thereby enhancing the level of port automation.

Description

A ship hatch data management method based on point cloud technology 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. Technical issues

[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. Technical Solutions

[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] S2, the hatch automatic identification and calculation module analyzes and calculates the hatch position and the hatch's spatial coordinates in the dock space rectangular coordinate system according to the automatic identification algorithm;

[0009] 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;

[0010] 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;

[0011] 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.

[0012] Specifically, S1 includes the following steps:

[0013] S11, parsing the raw data collected by the scanner into point data;

[0014] S12. Perform mathematical processing on the point data returned by the scanner. The single-point mathematical processing method is as follows:

[0015] 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 ground.

[0016] 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);

[0017] 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:

[0018] 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;

[0019] 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-coordinate, and generate a two-dimensional point cloud set;

[0020] S14. Compensate all point coordinates by:

[0021] 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.

[0022] S142. Compare the rotation angle with the case of 0 degrees, construct a right triangle based on the rotation angle and the y value, calculate the lengths of the opposite side and the adjacent side, and calculate the adjacent side length as the actual point y coordinate y1. 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).

[0023] 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, 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 to generate a point cloud model and coordinate file, which is the original point cloud file.

[0024] Specifically, S2 includes the following steps:

[0025] S21. Analyze and process the point cloud file and calculate the maximum y-value position y1 of the ship. 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 y-value centerline. The height change along the centerline 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 with actual coordinates of the variable. 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 the four boundary lines x4, y5, and x5 to obtain the coordinates of the four vertices.

[0027] S24. 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 height of the side. After obtaining the heights of the four sides, 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 way 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. Beneficial effects

[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] FIG1 is a module diagram of a ship hatch data management system according to the present invention;

[0036] FIG2 is a schematic diagram of the conversion of ship scanning point cloud data in S1 of the present invention;

[0037] FIG3 is a diagram of a ship point cloud model generated in S1 of the present invention;

[0038] FIG4 is a point cloud diagram of hatch identification and feature point selection in S2 of the present invention;

[0039] FIG5 is a point cloud diagram of the change in the ship's loading capacity 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. Best Mode for Carrying Out the Invention

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

[0042] As shown in Figure 1, 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. As shown in Figures 2 and 3, 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 structural parameters of the ship loader;

[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 ground.

[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-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 based on the rotation angle and the y value, calculate the lengths of the opposite side and the adjacent side, and calculate the adjacent side length as the actual point y coordinate y1. 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. 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, as shown in Figure 3.

[0058] S2. As shown in FIG4 , the hatch automatic identification and calculation module analyzes and calculates the hatch position and the hatch's spatial coordinates in the dock's rectangular coordinate system according to the automatic identification algorithm;

[0059] S2 includes the following steps:

[0060] S21. Analyze and process the point cloud file and calculate the maximum y-value position y1 of the ship (furthest from the dock). 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 y-value centerline. The height change along the centerline 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 with actual coordinates of the variable. 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 the four boundary lines x4, y5, and x5 to obtain the coordinates of the four vertices.

[0062] S24. 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 height of the side. After obtaining the heights of the four sides, 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, as shown in Figure 5, the ship attitude data compensation module compensates for the change in ship attitude caused by tides and loading factors during the cabin change process of the ship 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 way 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. Industrial Applicability

[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 method for managing ship hatch data based on point cloud technology, which is realized through a constructed ship hatch data management system, characterized in that, The system 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; When the system is in use, it includes the following steps: 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 in combination with the mechanism parameters of the ship unloader; S2. The hatch automatic recognition and calculation module analyzes and calculates the hatch position and the spatial coordinates of the hatch in the dock space rectangular coordinate system according to the automatic recognition algorithm; S3. The ship attitude data compensation module compensates for the change values caused by factors such as tide and loading volume during the cabin change process of the ship unloader to the ship attitude change, and updates the hatch coordinates; S4. Download the calculated hatch position coordinate information to the ship unloader PLC to guide the ship unloader to achieve unmanned and automated operation, thereby enhancing the port automation level; S5. After the ship loading operation is completed, the hatch data calibration and accumulation module stores the results after parsing the ship point cloud data and the ship operation information in the database. When the ship with the same hull number berths for operation next time, it is used for secondary correction of the scanned hatch data, to judge whether the scanning and data analysis programs are running normally, and 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 managing ship hatch data based on point cloud technology according to claim 1, characterized in that, S1 includes the following steps: S11. Parse the original data collected by the scanner into point position data; S12. Perform mathematical processing on the point position data returned by the scanner. The single-point mathematical processing method is: S121. Calculate the current scanning area: the angle value θ between the scanning point position and the direction perpendicular to the ground of the scanner, and the vertical height h of the scanner from the plane with the z-axis coordinate of 0, where h = h1 + h2, h1 is the vertical height of the scanning point position from the scanner, and h2 is the vertical height of the scanning point position from the ground; S122. Obtain the straight-line distance l between the scanning point position 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. d is the y value of the scanning point position in the rectangular coordinate system, construct a triangle with sides d, l, and angle θ, and calculate the lengths of the adjacent sides h1 and h2. h2 is the z value of the scanning point position in the rectangular coordinate system, that is, the coordinates of the single-scanning point position after rectangular coordinate system conversion are (d, h2); S13. The scanner performs a single-sector area scan, and the data forms a linear point cloud coordinate through superposition and positioning. The implementation method is: S131. Perform rectangular coordinate system conversion processing on all the point positions returned by the single scan of the scanner to form the (y, z) coordinates of all the point positions in the current area; S132. Obtain the large machine walking data in the PLC, complete the space rectangular coordinate system with the rotation center as the origin with the large machine walking data as the x-axis coordinate, and calculate the (x, y, z) coordinates of all the scanning point positions under the current x coordinate to generate a two-dimensional point cloud set; S14. Perform compensation processing on all the point position coordinates. The implementation method is: S141. According to the large machine rotation angle and pitch angle values, perform a trigonometric function processing on the coordinate values of all the point positions to ensure that the data is on the same plane; S142. Compare with the situation where the rotation angle is 0 degrees, construct a right triangle with the rotation angle and the y value, calculate the lengths of the opposite side and the adjacent side. The length of the adjacent side is the y coordinate y1 of the actual point position, and the actual x coordinate x1 is obtained by subtracting the length of the opposite side from the x coordinate. The same method is used for pitch. Process and convert all point positions to obtain the coordinates (x1, y1, z). S15. Monitor the change of the large machine walking data in real time. When the large machine starts the scanning program and the walking encoder changes, repeat the linear two-dimensional point cloud set generation operation according to the period and the change frequency. Stitch and overwrite the two-dimensional point cloud sets obtained multiple times to generate a point cloud model and a coordinate file, which is the original point cloud file.

3. The method for managing ship hatch data based on point cloud technology according to claim 2, characterized in that, S2 includes the following steps: S21. Analyze and process the point cloud file, calculate the position y1 with the maximum y value of the ship. The system default reads the y value constant y2 of the dock edge and the width w1 of the fender. Determine the ship width according to the values of y2 and y1, and obtain the y value of the ship center by taking the average value. Divide the point cloud into blocks according to the y value center line, and compare the height changes on the center line to determine the approximate position of the ship hatch. S22. Obtain the coordinates of two points, one in the upper left and the other in the lower right, at random positions inside the hatch. Decrease the x value of the upper left point to x1 and increase the y value to y1, increase the x value of the lower right point to x2 and decrease the y value to y2. During the movement, query the first point with an actual coordinate position for this variable, and continue to spread this point a certain range n in the changing direction. Calculate the average value y3 of the y values of all points with the x coordinate in the range of x1 + n. y3 - n / 2 is the boundary value y4 in the decreasing direction of the x value of this hatch. Use the same method to calculate x4, y5, x5 of the four boundary lines to obtain the coordinates of the four vertices. S24. Compare the elevation coordinates of all points from x to x1 + n, sort them from high to low, and take the average value of the z values of the highest k points as the height of this side. After obtaining the heights of the four sides, compare the sea and land sides, and compare the front and back sides. Take the two maximum values to get z1 and z2. Compare z1 and z2, the higher value is the hatch cover height, and the lower value is the hatch height. Thus, obtain the coordinate values of the four sides and four corners of all hatches, and determine the hatch coordinates and the hatch cover height.

4. The method for managing ship hatch data based on point cloud technology according to claim 3, characterized in that, S3 includes the following steps: S31. Monitor the cabin change signal, the large machine walking, rotation, and pitch encoders. After triggering the cabin change signal, when the encoder data of each mechanism is updated and reset, start the ship scanning program and generate a point cloud file of the ship segment during the cabin change process. Construct the point cloud model of this section of the ship in the same way as the overall ship scanning and modeling, screen the elevation characteristic values, and compare the characteristic values with the ship inclination and roll parameters. S32. Compare the point cloud files of the two scans before and after, calculate the hatch characteristic points of the scannable cabins, 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 according to the coordinate change amounts of the two scan results, and then infer the overall ship angle and height changes through the change amounts to update the overall ship model, thereby updating the hatch coordinate data in the PLC.

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