Schematic pipeline three-dimensional model generation method based on spatial topological relationship constraints

Abstract

The present invention relates to a method for generating a schematic three-dimensional pipeline model based on spatial topological relationship constraints. By integrating the data in the underground pipe network information data set into a unified coordinate system, extracting and retaining important attributes in the underground pipe network information, using roads and plots as spatial constraints, on the basis of ensuring the pipeline topological relationship, based on a random perturbation model with controllable noise and a spring-damping model to achieve desensitization and decryption while simulating small offsets in the positions of underground pipelines, continuously performing collision detection and conflict correction on the pre-set spatial constraint conditions, checking the spatial constraint conditions for the underground pipelines after each offset, and then based on the perturbed node coordinates of the underground pipelines and the retained attribute information, calling the CityGML standard template to generate a schematic three-dimensional pipeline model for the current underground pipe network information. In this way, not only is the desensitization and decryption of the underground pipeline information achieved, but more topological structures and spatial distribution characteristics of the underground pipelines are also retained.

Description

Technical Field

[0001] The present invention relates to the field of underground pipe network data processing, and particularly to a method for generating a schematic three-dimensional model of pipeline based on spatial topological relationship constraints. Background Art

[0002] The underground pipe network system is an important part of the urban pipe network system, and the pipeline information data of the underground pipe network system is of great significance for urban pipe network maintenance and dealing with emergencies.

[0003] In the existing management process of underground pipe network information data, insufficient sharing of pipeline information is likely to increase the risk of third parties damaging underground pipelines during construction. Since the current management of underground pipe networks still remains in the manual operation stage for a long time, it is difficult to cope with emergencies, reducing the efficiency of underground pipe network construction and maintenance. At the same time, the closed management of pipeline information is also likely to cause the underground pipe network management system to become a "zombie system", and its data cannot be effectively fed back or updated, thus forming a "data island". Therefore, realizing the sharing of underground pipe network information is an important measure to break the "data island" and improve the efficiency of underground pipe network maintenance and management.

[0004] Since underground pipeline information belongs to the category of confidentiality, measures such as pipeline decryption and desensitization methods need to be taken for strict confidentiality management. The existing decryption and desensitization methods for underground pipeline information are mainly the following forms: The first is the grid-based desensitization processing method, that is, converting pipeline data into map grids for desensitization to generate a desensitized layer; the second is the numerical and attribute desensitization method, that is, offsetting or blurring sensitive numerical values such as elevation and pipe diameter to reduce data accuracy, and at the same time deleting or replacing some confidential attributes to only retain basic geographic information; the third is a method that combines neural network transformation and Chebyshev polynomial model, and through control point perturbation and model coefficient iteration, irreversible desensitization of spatial data is achieved.

[0005] However, the existing underground pipeline information processing methods adopted to meet underground information sharing have deficiencies: they do not consider range control and the topological relationship between pipelines, which is likely to cause the pipeline position to deviate from the reasonable range, or cause errors in the topological relationship between pipelines, thus resulting in abnormal situations such as pipeline collisions or intersections.

[0006] Therefore, how to meet the sharing of underground pipeline information on the premise of ensuring the security and confidentiality of pipeline information and retaining the topological relationship between pipelines is a technical problem that urgently needs to be solved in the current field of underground pipeline information management. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints for the above-mentioned existing technologies. This method for generating a schematic pipeline three-dimensional model can ensure that the requirements for sharing underground pipeline information are met while ensuring the security and confidentiality of pipeline information and retaining the topological relationship between pipelines.

[0008] The technical solution adopted by the present invention to solve the above technical problems is as follows: A method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints, characterized by including the following steps:

[0009] Step 1, perform data integration and preprocessing on the underground pipe network information data set, integrate the data in the underground pipe network information data set into a unified coordinate system, and extract and retain important attributes in the underground pipe network information;

[0010] Step 2, preset spatial constraint conditions for restricting the spatial range of the distribution of underground pipe network pipelines based on the road surface and plot range involved in the underground pipe network;

[0011] Step 3, implement the position offset of underground pipelines based on a random perturbation model with controllable noise, and use a spring-damping model to constrain the spacing between the perturbed underground pipelines, so as to maintain the relative topological relationship while simulating the position offset of underground pipelines;

[0012] Step 4, perform collision detection and conflict correction on the preset spatial constraint conditions to ensure that the offset underground pipelines do not exceed the restricted spatial range of the distribution of underground pipe network pipelines;

[0013] Step 5, check the spatial constraint conditions for the underground pipelines after each offset to ensure that the position offset of the underground pipelines meets the spatial constraint conditions;

[0014] Step 6, based on the node coordinates after perturbation of the underground pipelines and the retained important attribute information, call the CityGML standard template to generate a schematic pipeline three-dimensional model for the current underground pipe network information.

[0015] Improved, in the method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints, the underground pipe network information data set includes underground pipeline information data, road information data, and plot information data, the important attributes include the basic attributes of the underground pipe network and the topological connection relationship, the basic attributes of the underground pipe network include the pipe diameter and material of the underground pipelines, and the topological connection relationship includes the topological connection relationships between valves, inspection wells, and pipeline connection points.

[0016] Further, in the method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints, the process of performing data integration and preprocessing on the underground pipe network information data set includes:

[0017] Step a1: Set the initial underground pipeline as a set of continuous line segments;

[0018] Step a2: Perform parameterization processing on each continuous line segment in the set of continuous line segments to obtain the continuous line segments after parameterization processing;

[0019] Step a3: Set the direction vectors of each continuous line segment after parameterization processing.

[0020] Further improvement: In the method for generating a schematic 3D pipeline model based on spatial topological relationship constraints, by using a gradient descent algorithm to optimize the objective function, ensure that the connected pipelines in the underground pipe network meet the condition of node collinearity.

[0021] Furthermore, in the method for generating a schematic 3D pipeline model based on spatial topological relationship constraints, the spatial constraint conditions include the maximum curvature change, the maximum offset, the maximum disturbance offset, the minimum disturbance offset, and the minimum safety distance between pipe segments; and the disturbance offset of the underground pipeline is between the maximum disturbance offset and the minimum disturbance offset.

[0022] Improvement: In the method for generating a schematic 3D pipeline model based on spatial topological relationship constraints, in step 4, use an octree or an R-tree to hierarchically organize the roads, plots, and pipelines involved to support fast spatial relationship query and location of collision areas.

[0023] Further, in the method for generating a schematic 3D pipeline model based on spatial topological relationship constraints, in step 4, when a collision area is detected, use the projection method to constrain the collision area to the road or plot boundary to complete the conflict correction operation.

[0024] Compared with the prior art, the advantages of the present invention are as follows: The method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints integrates the data in the underground pipe network information data set into a unified coordinate system, extracts and retains the important attributes in the underground pipe network information, and then uses roads and plots as spatial constraints. On the basis of ensuring the pipeline topological relationship, it realizes the position offset of underground pipelines based on a random perturbation model with controllable noise, and uses a spring-damping model to constrain the distance between the perturbed underground pipelines, so as to maintain the relative topological relationship while simulating the position offset of underground pipelines, and continuously performs collision detection and conflict correction on the preset spatial constraint conditions to ensure that the offset underground pipelines do not exceed the limited underground pipe network pipeline distribution space range, and checks the spatial constraint conditions for the underground pipelines after each offset to ensure that the position offset of the underground pipelines conforms to the spatial constraint conditions. Then, based on the perturbed node coordinates and retained attribute information of the underground pipelines, it calls the CityGML standard template to generate a schematic pipeline three-dimensional model for the current underground pipe network information. The generated schematic pipeline three-dimensional model not only realizes the desensitization and decryption of underground pipeline information, but also retains more topological structures and spatial distribution characteristics of underground pipelines, and meets the sharing application of underground pipe network information to a greater extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flowchart of the method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present invention will be further described in detail below with reference to the embodiments of the drawings.

[0027] This embodiment provides a method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints to ensure that the sharing requirements of underground pipeline information are met on the premise of ensuring the security and confidentiality of pipeline information and retaining the topological relationship between pipelines. Specifically, as shown in Figure 1 The method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints in this embodiment includes the following steps 1 to 6:

[0028] Step 1: Perform data integration and preprocessing on the underground pipe network information data set, integrate the data in the underground pipe network information data set into a unified coordinate system, and extract and retain the important attributes in the underground pipe network information; specifically, the underground pipe network information data set here includes underground pipeline information data, road information data, and plot information data, and the important attributes include the basic attributes and topological connection relationships of the underground pipe network. The basic attributes of the underground pipe network include the pipe diameter and material of the underground pipelines, and the topological connection relationships include the topological connection relationships between valves, manholes, and pipeline connection points.

[0029] Step 2, preset spatial constraint conditions for restricting the spatial range of the distribution of underground pipeline networks based on the road surfaces and plot ranges involved in the underground pipeline networks;

[0030] Step 3, implement the position offset of underground pipelines based on a noise-controlled random perturbation model, and use a spring-damping model to constrain the spacing between the perturbed underground pipelines, so as to maintain the relative topological relationship while simulating the position offset of underground pipelines;

[0031] Step 4, perform collision detection and conflict correction on the preset spatial constraint conditions to ensure that the offset underground pipelines do not exceed the restricted spatial range of the distribution of underground pipeline networks;

[0032] Step 5, check the spatial constraint conditions for the underground pipelines after each offset to ensure that the position offset of the underground pipelines conforms to the spatial constraint conditions; wherein, in this embodiment, the spatial constraint conditions here include the maximum curvature change amount, the maximum offset amount, the maximum perturbation offset amount, the minimum perturbation offset amount, and the minimum safety spacing between pipe segments; and, the perturbation offset amount of the underground pipelines is between the maximum perturbation offset amount and the minimum perturbation offset amount;

[0033] Step 6, based on the perturbed node coordinates of the underground pipelines and the retained important attribute information, call the CityGML standard template to generate a schematic 3D pipeline model for the current underground pipeline network information.

[0034] Specifically, in step 1 of this embodiment, the process of data integration and preprocessing of the underground pipeline network information data set includes the following steps a1 to a3:

[0035] Step a1, set the initial underground pipelines as a set of continuous line segments; wherein, the initial underground pipelines are marked as , ; M is the total number of continuous line segments in the set of continuous line segments, is the i-th continuous line segment in the set of continuous line segments;

[0036] Step a2, perform parameterization processing on each continuous line segment in the set of continuous line segments to obtain the parameterized continuous line segments; wherein, the parameterized continuous line segments are marked as :

[0037] ; ;

[0038] Wherein, is the starting point of the i-th continuous line segment , is the ending point of the i-th continuous line segment ;

[0039] Step a3, setting the direction vector of each parameterized continuous line segment; wherein the i-th continuous line segment The direction vector is marked as , .

[0040] In order to ensure that adjacent pipelines in an underground pipeline network meet the node collinearity condition, the schematic pipeline 3D model generation method of this embodiment optimizes the objective function using a gradient descent algorithm to ensure that adjacent pipelines in the underground pipeline network meet the node collinearity condition.

[0041] The objective function is set as follows:

[0042] ;

[0043] ;

[0044] in, is a node The initial position of is a node The initial position of and That is, the observed value, is the node's three-dimensional space coordinate ( , ) is the collinearity constraint determinant function, λ is the weight coefficient used to balance the node position change and the collinearity priority;

[0045] The node collinearity condition of adjacent pipelines is: and , there is a node position t i , making .

[0046] Specifically in this embodiment, the noise-controllable random perturbation model in step 3 is constructed as follows:

[0047] ;

[0048] in, is the i-th continuous line segment The starting point, Starting point The position after the disturbance in step 1, α is the global disturbance intensity coefficient, β is the attenuation factor that controls the attenuation speed of the disturbance with distance, s i is the cumulative walking distance from the current point to the starting point, is a random vector obeying anisotropic Gaussian distribution;

[0049] The spring-damper model in step 3 is constructed as follows:

[0050] ;

[0051] ; ;

[0052] Among them, is the sum of the elastic damping forces between node and all its adjacent nodes, J represents the total number of all adjacent nodes of node , is the elastic damping force between node and its j-th adjacent node , φ represents the elastic coefficient. For example, this φ is 5 to 10 times the diameter of the underground pipeline; d min represents the minimum safety distance between adjacent pipelines in the underground pipeline. For example, d min is 1.5 times the diameter of the underground pipeline; γ represents the damping coefficient. For example, the value range of γ is 10% to 20%; represents the velocity of node , represents the velocity of adjacent node ; Δt represents the time step. For example, the value of Δt is 0.1, m i represents the mass of node . For example, m i takes the unit mass 1; represents the position of node after the t-th perturbation. The initial position of node is the position after noise-controllable random perturbation, represents the velocity of node at the position where it is located after the t-th perturbation. The initial velocity of node is 0;

[0053] For example, in this embodiment, part of the code segment of the perturbation model in step 3 is as follows:

[0054] import numpy as np

[0055] class ControllableRandomNoisePerturbation:

[0056] def __init__(self, alpha = 1.0, beta = 1.0, anisotropic_cov = None):

[0057] """

[0058] Initialize the noise-controllable random perturbation model

[0059] Parameters:

[0060] - alpha: Global perturbation intensity coefficient

[0061] - beta: Decay factor that controls the decay rate of perturbation with distance

[0062] - anisotropic_cov: Covariance matrix (3x3) of anisotropic Gaussian distribution

[0063] """

[0064] self.alpha = alpha

[0065] self.beta = beta

[0066] # Set the default anisotropic covariance matrix

[0067] if anisotropic_cov is None:

[0068] self.anisotropic_cov = np.array([[1.0, 0.5, 0.2], [0.3, 1.0,0.4], [0.5, 0.3, 1.0]])

[0069] else:

[0070] self.anisotropic_cov = anisotropic_cov

[0071] def perturb_segment(self, start_point, current_point,cumulative_distance):

[0072] """

[0073] Apply controllable random perturbations to the end points on the pipeline segment

[0074] Parameters:

[0075] - start_point: Initial position of the end point

[0076] - current_point: Position of the end point after the previous perturbation

[0077] - cumulative_distance: Cumulative walking distance from the current point to the starting point

[0078] Returns:

[0079] - New position after perturbation

[0080] """

[0081] In addition, it should be noted that in Step 4, an octree or an R-tree is used to hierarchically organize the roads, plots, and pipelines involved to support fast spatial relationship queries and locate the collision area. Of course, in Step 4, when a collision area is detected, the projection method is used to constrain the collision area to the road or plot boundary to complete the conflict correction operation; where: The conflict correction operation method is as follows: ;

[0082] where, is the adjusted position of the node, is the position of the outer node of the current spatial constraint range, ε is the adjustment step length along the normal direction, is the normal vector of the conflict surface corresponding to the collision area. According to actual needs, in this embodiment, the adjustment step length ε is 50% - 80% of the conflict distance.

[0083] Although the preferred embodiments of the present invention have been described in detail above, it should be clearly understood that various changes and modifications can be made to the present invention for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A schematic pipeline 3D model generation method based on spatial topological relationship constraints, characterized in that: The steps include: Step 1: perform data integration and preprocessing on the underground pipe network information data set, integrate the data in the underground pipe network information data set into a unified coordinate system, and extract and retain important attributes of the underground pipe network information; Step 2: pre-set spatial constraints that limit the spatial distribution range of underground pipelines based on the road surface and land parcels involved in the underground pipeline network; Step 3: Implement underground pipeline position offset based on a noise-controllable random perturbation model, and use a spring-damper model to constrain the underground pipeline spacing after the perturbation to maintain the relative topological relationship while simulating the underground pipeline position offset; Step 4: perform collision detection and conflict correction on the pre-set spatial constraints to ensure that the underground pipelines after displacement do not exceed the restricted underground pipeline network distribution space range; Step 5: Check the spatial constraints of the underground pipelines after each shift to ensure that the position shift of the underground pipelines meets the spatial constraints. Step 6: Based on the disturbed node coordinates and the retained important attribute information of the underground pipeline, the CityGML standard template is called to generate a schematic pipeline 3D model for the current underground pipeline network information; wherein: The noise-controllable random perturbation model in step 3 is constructed as follows: ； in, is the i-th continuous line segment The starting point, As a starting point The position after the disturbance in step 1, α is the global disturbance intensity coefficient, β is the attenuation factor that controls the attenuation speed of the disturbance with distance, s i is the cumulative walking distance from the current point to the starting point, is a random vector obeying anisotropic Gaussian distribution; The spring-damper model in step 3 is constructed as follows: ； ； ； in, For nodes The sum of the elastic damping forces between the node and all its adjacent nodes, J represents the node The total number of all adjacent nodes, For nodes and its jth adjacent node The elastic damping force between min It represents the minimum safe distance between adjacent pipelines in underground pipelines, γ represents the damping coefficient, Representation node speed, Indicates adjacent nodes speed; Δt represents the time step, m i Representation node quality, Representation node At the position after the tth disturbance, the node The initial position of is the position after the noise-controlled random perturbation. Representation node The velocity at the location after the tth disturbance, node The initial velocity is 0.

2. The method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints according to claim 1, characterized in that: The underground pipeline network information data set includes underground pipeline information data, road information data and plot information data. The important attributes include the basic attributes and topological connection relationships of the underground pipeline network. The basic attributes of the underground pipeline network include the diameter and material of the underground pipeline. The topological connection relationship includes the topological connection relationship between valves, inspection wells and pipeline connection points.

3. The method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints according to claim 2, characterized in that: The process of data integration and preprocessing of underground pipe network information data sets includes: Step a1, setting the initial underground pipelines as a set of continuous line segments; Step a2, performing parameterization processing on each continuous line segment in the continuous line segment set to obtain parameterized continuous line segments; Step a3: setting the direction vector of each parameterized continuous line segment.

4. The method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints according to claim 3, characterized in that: By optimizing the objective function with the help of gradient descent algorithms, it is ensured that the interconnected pipe lines in the underground pipeline network meet the node collinearity condition.

5. The method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints according to claim 4, characterized in that: The spatial constraints include maximum curvature variation, maximum offset, maximum disturbance offset, minimum disturbance offset and minimum safety distance between pipe sections; and the disturbance offset of the underground pipeline is between the maximum disturbance offset and the minimum disturbance offset.

6. The method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints according to claim 5, characterized in that: In step 4, an octree or R-tree is used to hierarchically organize the involved roads, plots, and pipelines to support fast spatial relationship queries and locate collision areas.

7. The method for generating a schematic pipeline three-dimensional model based on spatial topological relationship constraints according to claim 6, characterized in that: In step 4, when a collision area is detected, a projection method is used to constrain the collision area to the road or land boundary to complete the conflict correction operation.

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