CN-121982209-A - Underground cable three-dimensional imaging method and device based on X-ray data

CN121982209ACN 121982209 ACN121982209 ACN 121982209ACN-121982209-A

Abstract

The application provides an underground cable three-dimensional imaging method based on X-ray data, which comprises the steps of obtaining the X-ray data used for detecting an underground cable, determining compression projection data and an initial attenuation coefficient field of the underground cable according to the X-ray data, carrying out iterative updating on a deformation field and the attenuation coefficient field of the underground cable based on the compression projection data, the initial attenuation coefficient field and a preset objective function until the attenuation coefficient field of the underground cable converges to obtain the objective attenuation coefficient field, wherein the objective function is used for realizing sparse reconstruction through geometric priori constraint of the cable, carrying out parameter optimization by utilizing the updated attenuation coefficient field in each iteration round, and carrying out three-dimensional model fusion based on the objective attenuation coefficient field and the updated deformation field in each iteration round to obtain a three-dimensional image of the underground cable. Therefore, the high-efficiency, accurate and nondestructive detection of the underground cable can be realized.

Inventors

TANG QI
CHEN ZHIPING
HE SHENGHONG
WANG ZHIGANG

Assignees

广东电网有限责任公司佛山供电局

Dates

Publication Date: 20260505
Application Date: 20260127

Claims (10)

1. A method for three-dimensional imaging of a subsurface cable based on X-ray data, the method comprising: acquiring X-ray data for detecting an underground cable, and determining compressed projection data and an initial attenuation coefficient field of the underground cable according to the X-ray data; Iteratively updating the deformation field and the attenuation coefficient field of the underground cable based on the compressed projection data, the initial attenuation coefficient field and a preset objective function until the attenuation coefficient field of the underground cable converges to obtain a target attenuation coefficient field, wherein the objective function is used for realizing sparse reconstruction through cable geometric priori constraint, and in each iteration, parameter optimization is performed by utilizing the updated attenuation coefficient field in the current iteration round; And carrying out three-dimensional model fusion based on the target attenuation coefficient field and the updated deformation field in each iteration round to obtain a three-dimensional image of the underground cable.
2. The method of three-dimensional imaging of an underground cable based on X-ray data of claim 1, wherein the X-ray data comprises an X-ray source energy spectrum distribution, a detection angle candidate set, and an energy spectrum matrix, and wherein the step of determining compressed projection data and an initial attenuation coefficient field of the underground cable from the X-ray data comprises: Selecting an optimal projection angle meeting incoherence maximization constraint conditions from the detection angle candidate set, and acquiring the compressed projection data according to the optimal projection angle; and solving the volume fraction of each material in the underground cable according to the compressed projection data and the energy spectrum matrix, and calculating the initial attenuation coefficient field according to the volume fraction of each material and the attenuation coefficient of the material under the reference energy in the energy spectrum distribution of the X-ray source.
3. The method according to claim 1, wherein the step of iteratively updating the deformation field and the attenuation coefficient field of the underground cable based on the compressed projection data, the initial attenuation coefficient field and a preset objective function until the attenuation coefficient field of the underground cable converges to obtain a target attenuation coefficient field comprises: Taking the initial attenuation coefficient field as a current attenuation coefficient field of a current iteration round, solving a current deformation field through a preset Horn-Schunck optical flow equation according to the current attenuation coefficient field, and correcting the current attenuation coefficient field by utilizing the current deformation field; the target function is used as a current target function of a current iteration round, the corrected current attenuation coefficient field is updated by adopting the current target function, and parameters of the current target function are optimized according to the updated current attenuation field; And taking the updated current attenuation coefficient field as the current attenuation coefficient field of the next round, taking the optimized current objective function as the current objective function of the next round, and continuously updating the deformation field and the attenuation coefficient field of the underground cable until the attenuation coefficient field of the underground cable converges to obtain the target attenuation coefficient field.
4. A method of three-dimensional imaging of a subsurface cable based on X-ray data according to claim 3, wherein the expression of the objective function is: Wherein, the The data-fidelity term is represented as such, The term of the sparse constraint is represented, A continuity constraint term is represented as a term of continuity, Representing the term of the symmetry constraint, Representing the current attenuation coefficient field, In order to compress the observation matrix, For the compressed projection data to be used, For the sparsity constraint term parameter, For the continuity constraint term parameter(s), For the symmetry constraint term parameter, For the axial gradient operator, Is a radially symmetric constraint.
5. The method for three-dimensional imaging of an underground cable based on X-ray data according to claim 3, wherein the expression of the Horn-Schunck optical flow equation is: Wherein, the Representing the current deformation field of the object, Representing the current updated attenuation coefficient field, Representation of The partial derivative with respect to time is, Representing the regularized weights of the model, Representation of Is used for the spatial gradient of (a), Representation of Is a spatial gradient of (c).
6. The method of three-dimensional imaging of underground cable based on X-ray data according to claim 4, wherein the expression for parameter optimization of the objective function is: Wherein, the Represent the first Constraint term parameters, at The updated value of the next iteration, Represents the number of dimensions to which the constraint term corresponds, The desired value is indicated to be the desired value, Representing the current iteration round Is used for the attenuation coefficient field of (a), Represent the first The number of constraint terms is a function of the number of constraint terms, The term of the sparse constraint is represented, A continuity constraint is represented as a function of the continuity constraint, Representing symmetry constraints.
7. The method of three-dimensional imaging of an underground cable based on X-ray data according to claim 1, wherein the step of performing three-dimensional model fusion based on the target attenuation coefficient field and the updated deformation field in each iteration round to obtain a three-dimensional image of the underground cable comprises: generating a three-dimensional image of the subsurface cable using the following expression: Wherein, the Representing a three-dimensional image of the subsurface cable, The spatial coordinates are represented as such, The time is represented by the time period of the day, Representing the field of attenuation coefficients of the object, Representing the updated deformation field in each iteration round, Representing the time index.
8. A subsurface cable three-dimensional imaging apparatus based on X-ray data, the apparatus comprising: The X-ray data acquisition module is used for acquiring X-ray data for detecting the underground cable and determining compressed projection data and an initial attenuation coefficient field of the underground cable according to the X-ray data; The target attenuation coefficient field determining module is used for carrying out iterative updating on the deformation field and the attenuation coefficient field of the underground cable based on the compressed projection data, the initial attenuation coefficient field and a preset target function until the attenuation coefficient field of the underground cable converges to obtain a target attenuation coefficient field, the target function is used for realizing sparse reconstruction through cable geometric priori constraint, and in each iteration, the updated attenuation coefficient field in the current iteration round is utilized for parameter optimization; And the three-dimensional image determining module is used for carrying out three-dimensional model fusion based on the target attenuation coefficient field and the updated deformation field in each iteration round to obtain a three-dimensional image of the underground cable.
9. A storage medium having stored therein computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of the method for three-dimensional imaging of a subsurface cable based on X-ray data as claimed in any one of claims 1 to 7.
10. A computer device includes one or more processors and a memory; Stored in the memory are computer readable instructions which, when executed by the one or more processors, perform the steps of the X-ray data based three-dimensional imaging method of a subsurface cable as claimed in any one of claims 1 to 7.

Description

Underground cable three-dimensional imaging method and device based on X-ray data Technical Field The application relates to the technical field of power system equipment detection, in particular to a method and a device for three-dimensional imaging of an underground cable based on X-ray data. Background Underground cables are widely laid on urban roads and industrial parks as important infrastructure for urban power transmission, and the running state of the underground cables is directly related to the safety and stability of a power system. However, in the long-term burying and running process, the underground cable is easily affected by factors such as external environment change, mechanical stress, aging and the like, hidden dangers such as insulation degradation, metal corrosion and the like appear, and if the hidden dangers cannot be detected and eliminated in time, power failure accidents can be caused, so that larger economic loss is brought. Therefore, how to efficiently and accurately perform nondestructive testing and imaging on underground cables is always an important point of attention in the field of power operation and maintenance. Currently, conventional detection methods typically require either disconnection of the cable or inference of internal status depending on external test data. However, the method has obvious limitation, not only is the detection process complicated, but also secondary damage to the cable is possibly caused by improper operation, especially when a metal structure is imaged, the newly generated damage is more prominent in the imaging result, the true state of the original defect is covered, and the misjudgment risk is increased. Disclosure of Invention The present application aims to solve at least one of the above technical drawbacks, and in particular, how to efficiently and accurately perform nondestructive inspection and imaging on a subsurface cable in the prior art. In a first aspect, the present application provides a method for three-dimensional imaging of a subsurface cable based on X-ray data, the method comprising: acquiring X-ray data for detecting the underground cable, and determining compressed projection data and an initial attenuation coefficient field of the underground cable according to the X-ray data; Iteratively updating a deformation field and an attenuation coefficient field of the underground cable based on compressed projection data, an initial attenuation coefficient field and a preset objective function until the attenuation coefficient field of the underground cable converges to obtain a target attenuation coefficient field, wherein the objective function is used for realizing sparse reconstruction through cable geometric priori constraint, and in each iteration, parameter optimization is performed by utilizing the updated attenuation coefficient field in the current iteration round; and carrying out three-dimensional model fusion based on the target attenuation coefficient field and the updated deformation field in each iteration round to obtain a three-dimensional image of the underground cable. In one embodiment, the X-ray data includes an X-ray source energy spectrum distribution, a detection angle candidate set and an energy spectrum matrix, and the step of determining compressed projection data and an initial attenuation coefficient field of the subsurface cable from the X-ray data comprises: selecting an optimal projection angle meeting incoherence maximization constraint conditions from a detection angle candidate set, and acquiring compressed projection data according to the optimal projection angle; and solving the volume fraction of each material in the underground cable according to the compressed projection data and the energy spectrum matrix, and calculating an initial attenuation coefficient field according to the volume fraction of each material and the attenuation coefficient of each material under reference energy in the energy spectrum distribution of the X-ray source. In one embodiment, based on the compressed projection data, the initial attenuation coefficient field and a preset objective function, iteratively updating the deformation field and the attenuation coefficient field of the underground cable until the attenuation coefficient field of the underground cable converges, and obtaining the objective attenuation coefficient field, the method comprises the steps of: Taking the initial attenuation coefficient field as a current attenuation coefficient field of a current iteration round, solving a current deformation field through a preset Horn-Schunck optical flow equation according to the current attenuation coefficient field, and correcting the current attenuation coefficient field by utilizing the current deformation field; Using the objective function as a current objective function of the current iteration round, updating the corrected current attenuation coefficient field by adopting the current objective