Method for measuring and calculating windward area of ship in three-dimensional space

Abstract

The invention discloses a ship windward area measuring and calculating method in a three-dimensional space. The ship windward area measuring and calculating method comprises the steps that S1, a CAD drawing of a ship to be calculated is acquired; s2, three-dimensional modeling software is used, and based on the NURBS curved surface modeling technology, solid models of the ship body and the structure above the deck surface are constructed; s3, establishing a three-dimensional coordinate system taking the gravity center of the ship body as an original point; s4, wind direction parameters are defined as an azimuth angle and a pitch angle under the spherical coordinate system, and a wind direction unit vector is formed; s5, establishing a camera in a three-dimensional space according to the wind direction, and arranging a camera at the position away from the ship body feature point in the reverse direction of the wind direction; and S6, setting the background of the ship model to be completely transparent, starting a ray tracing rendering engine, and outputting an orthographic projection image with the resolution of M * N pixels. According to the method, efficient and accurate measurement and calculation of the windward area of the ship body are realized through accurate three-dimensional modeling and spatial analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind power engineering, and in particular to a method for measuring the windward area of ​​a ship in three-dimensional space. Background Art

[0002] In the field of offshore wind power, the hull is an important carrier for the transportation, installation and maintenance of offshore wind power equipment, and its stability analysis is a key link to ensure the safety of operations. The windward area is one of the important factors affecting the stability of the hull. Accurately measuring the windward area of ​​the hull is crucial for evaluating the stress and stability of the hull under wind loads. At present, most methods for measuring the windward area of ​​the hull are based on two-dimensional planes, which makes it difficult to fully and accurately consider the complex external structure of the hull in three-dimensional space and the actual wind conditions under different wind directions and wind speeds. Various types of equipment and structural components on the hull have different orientations and shapes in three-dimensional space and are mutually shielded. Traditional methods may ignore the impact of these details on the windward area, resulting in large errors in the measurement results.

[0003] Existing methods lack effective three-dimensional spatial analysis capabilities when dealing with complex sea conditions and changing wind directions, and are unable to provide reliable windward area data for ship stability analysis in real time and accurately.

[0004] Therefore, a method for measuring the windward area of ​​a ship in three-dimensional space is provided. Summary of the Invention

[0005] The purpose of the present invention is to overcome the existing defects and provide a method for measuring the windward area of ​​a ship in three-dimensional space, which realizes efficient and accurate measurement of the windward area of ​​the hull through precise three-dimensional modeling and spatial analysis.

[0006] The technical solution to achieve the above purpose is:

[0007] A method for calculating the windward area of ​​a ship in three-dimensional space, comprising:

[0008] Step S1, obtaining a CAD (computer-aided design) drawing of the ship to be calculated;

[0009] Step S2, using 3D modeling software and NURBS (a modeling method) surface modeling technology to build a solid model of the hull and the structure above the deck;

[0010] Step S3, establishing a three-dimensional coordinate system with the ship's center of gravity as the origin, wherein the X-axis points to the bow, the Y-axis points to the starboard side, and the Z-axis points vertically upward;

[0011] Step S4, defining the wind direction parameters as the azimuth angle α and the pitch angle β in the spherical coordinate system, forming a wind direction unit vector v = (sinβcosα, sinβsinα, cosβ);

[0012] Step S5, establishing a camera in three-dimensional space according to the wind direction, and setting the camera at a distance L from the hull feature point in the opposite direction of the wind direction;

[0013] Step S6, setting the ship model background to be completely transparent, enabling the ray tracing rendering engine, and outputting an orthographic projection image with a resolution of M×N pixels;

[0014] Step S7: record the pixel size of the rendered image and calculate the actual total area S of the camera's viewing angle imaging. 总 =W×H;

[0015] Step S8, preprocessing the image, using the Python OpenCV library to read the rendered image and convert it into a grayscale image;

[0016] Step S9: Binarize the image, take the pixels with Alpha channel ≥ 128 as the ship area, and count the number of pixels P occupied by the ship using the connected domain analysis algorithm. 船 , total number of pixels P 总 =M×N;

[0017] Step S10, calculating the frontal area;

[0018] Step S11, defining the angle step, executing steps S3-S10, automatically traversing all target angle combinations through a loop script, and recording the windward area value corresponding to each angle.

[0019] Preferably, in step S1, the CAD drawings of the ship include but are not limited to hull line drawings, superstructure structural drawings and equipment layout drawings.

[0020] Preferably, in step S2, the structure includes but is not limited to the hull, deck equipment, superstructure and crane.

[0021] Preferably, in step S5, the feature point L satisfies that the camera viewing angle range covers the entire hull, and the camera optical axis direction is aligned with the wind direction unit vector v.

[0022] Preferably, in step S7, the range size W×H is calculated as follows:

[0023] W = 2Ltan(θx / 2);

[0024] H = 2Ltan(θy / 2);

[0025] Where θx is the horizontal field of view angle, θy is the vertical field of view angle, and L is the distance between the camera and the feature point of the hull in the opposite direction of the wind.

[0026] Preferably, in step S10, the calculation formula of the frontal area is as follows:

[0027] S 迎风 =S 总 ×P 船 / P 总 ;

[0028] Where S 总 It is the actual total area imaged by the camera's field of view.

[0029] The beneficial effects of the present invention are as follows: the present invention can fully consider the complex structure of the hull in three-dimensional space and the actual wind conditions, and realize efficient and accurate measurement of the windward area of ​​the hull through precise three-dimensional modeling and spatial analysis; specifically, the present invention aims to solve the problems of insufficient processing of the complex structure of the hull and low measurement accuracy of traditional measurement methods in three-dimensional space, and provide more accurate and reliable windward area data for the stability analysis of offshore wind power hulls, thereby improving the safety and stability of the hull in offshore operations and meeting the high standards of offshore wind power projects for hull stability analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a flow chart of a method for calculating the windward area of ​​a ship in three-dimensional space. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0032] The present invention will be further described below with reference to the accompanying drawings.

[0033] With the rapid development of the offshore wind power industry, the requirements for the accuracy and efficiency of hull stability analysis are becoming increasingly higher. A method for measuring the windward area of ​​the hull in three-dimensional space is needed to improve the accuracy and reliability of hull stability analysis.

[0034] like Figure 1 As shown, a method for calculating the windward area of ​​a ship in three-dimensional space includes:

[0035] Step S1, obtaining the CAD drawing of the ship to be calculated.

[0036] In the embodiment, the CAD drawings of the ship include but are not limited to hull line drawings, superstructure structure drawings and equipment layout drawings, and the accuracy is required to reach 1mm level.

[0037] Step S2: Using 3D modeling software, a solid model of the hull and the structures above the deck is constructed based on NURBS surface modeling technology.

[0038] In the embodiment, the structure includes but is not limited to the hull, deck equipment, superstructure and crane, ensuring that the geometric features of the hollow structure and curved surface parts are completely preserved.

[0039] Step S3: establishing a three-dimensional coordinate system with the ship's center of gravity as the origin, wherein the X-axis points to the bow, the Y-axis points to the starboard side, and the Z-axis is vertically upward.

[0040] Step S4 , defining the wind direction parameters as the azimuth angle α and the pitch angle β in the spherical coordinate system, forming a wind direction unit vector v=(sinβcosα, sinβsinα, cosβ).

[0041] Step S5: Establish a camera in the three-dimensional space according to the wind direction, and set the camera at a distance L from the hull feature point in the opposite direction of the wind direction.

[0042] In the embodiment, the feature point L satisfies that the camera viewing angle range covers the entire hull, and the camera optical axis direction is aligned with the wind direction unit vector v.

[0043] Step S6: Set the ship model background to be completely transparent, enable the ray tracing rendering engine, and output an orthographic projection image with a resolution of M×N pixels.

[0044] Step S7: record the pixel size of the rendered image and calculate the actual total area S of the camera's viewing angle imaging. 总 =W×H.

[0045] In the embodiment, the range size W×H is calculated as follows:

[0046] W = 2Ltan(θx / 2);

[0047] H = 2Ltan(θy / 2);

[0048] Where θx is the horizontal field of view angle, θy is the vertical field of view angle, and L is the distance between the camera and the feature point of the hull in the opposite direction of the wind.

[0049] Step S8: pre-process the image, use the Python OpenCV library to read the rendered image, and convert it into a grayscale image.

[0050] Step S9: Binarize the image, take the pixels with Alpha channel ≥ 128 as the ship area, and count the number of pixels P occupied by the ship using the connected domain analysis algorithm. 船 , total number of pixels P 总 =M×N.

[0051] Step S10: calculating the frontal area.

[0052] In the embodiment, the calculation formula of the windward area is as follows:

[0053] S 迎风 =S 总 ×P 船 / P 总 ;

[0054] Where S 总 It is the actual total area imaged by the camera's field of view.

[0055] Step S11, define the angle step size, execute steps S3-S10, automatically traverse all target angle combinations through the loop script, and record the windward area value corresponding to each angle.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the windward area of ​​a ship in three-dimensional space, characterized in that: include: Step S1, obtaining the CAD drawing of the ship to be calculated; Step S2, using 3D modeling software and NURBS surface modeling technology to build a solid model of the hull and the structure above the deck; Step S3, establishing a three-dimensional coordinate system with the ship's center of gravity as the origin, wherein the X-axis points to the bow, the Y-axis points to the starboard side, and the Z-axis points vertically upward; Step S4, defining the wind direction parameters as the azimuth angle α and the pitch angle β in the spherical coordinate system, forming a wind direction unit vector v = (sinβcosα, sinβsinα, cosβ); Step S5, establishing a camera in three-dimensional space according to the wind direction, and setting the camera at a distance L from the hull feature point in the opposite direction of the wind direction; Step S6, setting the ship model background to be completely transparent, enabling the ray tracing rendering engine, and outputting an orthographic projection image with a resolution of M×N pixels; Step S7: record the pixel size of the rendered image and calculate the actual total area S of the camera's viewing angle imaging. 总 =W×H; Step S8, preprocessing the image, using the Python OpenCV library to read the rendered image and convert it into a grayscale image; Step S9: Binarize the image, take the pixels with Alpha channel ≥ 128 as the ship area, and count the number of pixels P occupied by the ship using the connected domain analysis algorithm. 船 , total number of pixels P 总 =M×N; Step S10, calculating the frontal area; Step S11, defining the angle step, executing steps S3-S10, automatically traversing all target angle combinations through a loop script, and recording the windward area value corresponding to each angle.

2. The method for calculating the windward area of ​​a ship in three-dimensional space according to claim 1, characterized in that: In step S1, the CAD drawings of the ship include but are not limited to hull line drawings, superstructure structural drawings and equipment layout drawings.

3. The method for calculating the windward area of ​​a ship in three-dimensional space according to claim 1, characterized in that: In step S2, the structure includes but is not limited to the hull, deck equipment, superstructure and crane.

4. The method for calculating the windward area of ​​a ship in three-dimensional space according to claim 1, characterized in that: In step S5, the feature point L satisfies the requirement that the camera viewing angle covers the entire hull, and the camera optical axis direction is aligned with the wind direction unit vector v.

5. The method for calculating the windward area of ​​a ship in three-dimensional space according to claim 1, characterized in that: In step S7, the range size W×H is calculated as follows: W = 2Ltan(θx / 2); H = 2Ltan(θy / 2); Where θx is the horizontal field of view angle, θy is the vertical field of view angle, and L is the distance between the camera and the feature point of the hull in the opposite direction of the wind.

6. The method for calculating the windward area of ​​a ship in three-dimensional space according to claim 1, characterized in that: In step S10, the calculation formula of the windward area is as follows: S 迎风 =S 总 ×P 船 / P 总 ; Where S 总 It is the actual total area imaged by the camera's field of view.

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