Single-SAR Structural Deformation Detection Using 3D Reference Points
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Solution Overview
Problem
Current SAR technology-based deformation detection methods require paired SAR images with the same shooting geometry before and after deformation, limiting their applicability and preventing prompt detection of deformations in structures like overhead power line supports.
Innovation Solution
A method using single SAR images to detect deformations by acquiring georeferenced data of predefined points, transforming and comparing expected and actual positions of these points in a SAR image to identify and estimate deformations or damages without requiring pre- and post-deformation images with the same shooting geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If paired SAR images with the same shooting geometry are used for deformation detection, then measurement precision is improved, but loss of time increases due to the difficulty of acquiring both pre- and post-deformation images
Solution Approach 1:
The method stores georeferenced data of predefined points of interest representing the 3D geometry of the structure in its undeformed state before any deformation occurs. This preliminary action allows the system to have reference data ready for immediate comparison with post-deformation SAR images, eliminating the need to acquire pre-deformation images at the time of detection.
Solution Approach 2:
The method creates a digital copy of the structure's geometry through georeferenced data of predefined points of interest. This copy serves as a reference model that can be transformed and compared against actual post-deformation SAR images, replacing the need for physical pre-deformation image acquisition.
2Reliability
If paired SAR images with the same shooting geometry are required, then reliability of deformation detection is improved, but device complexity increases due to the need for multiple image acquisitions and geometric matching
Solution Approach 1:
The method extracts only the essential reference information (georeferenced coordinates of predefined points of interest) from the structure's geometry, separating this critical data from the need for complete pre-deformation SAR images. This extraction simplifies the system by removing the requirement for complex pre-image acquisition and geometric matching procedures.
Solution Approach 2:
The georeferenced data of predefined points of interest is acquired and stored in advance, representing the structure's 3D geometry without deformations. This preliminary capture of reference data simplifies the detection process by eliminating the need for complex pre- and post-image pairing and geometric alignment operations.
3Productivity
If single SAR images are used for deformation detection, then productivity is improved by enabling prompt detection, but measurement precision may worsen compared to paired image methods
Solution Approach 1:
The method uses a digital copy (georeferenced data of predefined points of interest) of the structure's undeformed geometry as a reference model. This copy can be instantly transformed and compared with post-deformation SAR images, enabling rapid detection while maintaining precision through accurate coordinate comparison.
Solution Approach 2:
The method transforms the reference georeferenced data into the reference coordinate system of the SAR image, adding a dimensional transformation step that enables direct comparison between the reference model and actual SAR image data. This dimensional transformation allows single-image detection to achieve precision comparable to paired-image methods.
Data Source
AI summary
The invention concerns a method (1) to detect deformations of, and/or damages to, structures permanently arranged on the earth's surface. In particular, said method (1) comprises: acquiring (11) georeferencing data indicative of geographical reference positions of predefined points of interest of a given structure to be monitored permanently arranged on the earth's surface, wherein said predefined points of interest are representative of a 3D geometry of the given structure without deformations and damages; acquiring (12) a SAR image of an area of the earth's surface where the given structure is arranged, wherein said SAR image is associated with a given reference coordinate system; transforming (13) the geographical reference positions of the predefined points of interest into corresponding expected positions in the given reference coordinate system associated with the acquired SAR image so as to carry out a reprojection of the 3D geometry of the given structure without deformations and damages on the acquired SAR image; identifying (14) in the acquired SAR image the predefined points of interest of the given structure; determining (15) actual positions in the given reference coordinate system associated with the acquired SAR image of the predefined points of interest identified in said SAR image; making a comparison (16) between the expected positions of the predefined points of interest and the corresponding actual positions in the acquired SAR image; and detecting (17) one or more deformations of, and/or one or more damages to, said given structure on the basis of the comparison made.