3D X-Ray Part Inspection Using Iterative Projection Alignment
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Solution Overview
Problem
Non-destructive testing (NDT) of aeronautical parts using X-ray radiography is hindered by image artifacts such as beam hardening and Compton scattering, leading to unreliable and laborious manual analysis, especially when only a limited number of radiographic images are used, which complicates the characterization of 3D geometry and dimensional conformity.
Innovation Solution
A method and system that utilizes a volumetric modeling process to generate a more accurate 3D geometry model of the part by aligning acquired and simulated radiographic images, accounting for projective geometry and image artifacts, and iteratively refining parameters to minimize residuals between simulated and observed projections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple x-ray sources and detectors are used to enable multi-planar reconstruction, then image quality and defect detection capability are improved, but device complexity and cost increase
Solution Approach 1:
The inspection system is divided into multiple independent x-ray source-detector pairs, each capable of operating independently to capture images from different angles. This segmentation allows the system to achieve multi-planar reconstruction capabilities while maintaining modular architecture that simplifies individual component design and maintenance.
Solution Approach 2:
Each x-ray source-detector pair is designed to perform multiple functions: capturing images in different planes (transverse, sagittal, coronal), generating 3D volumetric data, and enabling various reconstruction algorithms. This multi-functionality reduces the need for specialized components for each imaging mode, thereby reducing overall system complexity.
2Measurement precision
If multiple x-ray sources and detectors are used to enable multi-planar reconstruction, then image quality and defect detection capability are improved, but cost increases
Solution Approach 1:
The system uses multiple independent x-ray source-detector pairs that can be manufactured and tested separately using standardized components. This segmentation enables parallel manufacturing processes and reduces the need for custom-built integrated systems, thereby lowering overall manufacturing costs while maintaining high defect detection capability.
Solution Approach 2:
The system allows flexible configuration of x-ray source parameters (energy, intensity, focal spot size) and detector parameters (resolution, field of view) to optimize performance for different inspection requirements. This parameter adjustability enables the use of cost-effective components that can be tuned to achieve the required measurement precision without over-specifying expensive equipment.
3Measurement precision
If x-ray images are acquired from multiple angles and processed through multi-planar and 3D reconstruction algorithms, then inspection accuracy is improved, but processing time increases
Solution Approach 1:
The system performs preliminary processing of raw x-ray images from multiple angles immediately after acquisition, including noise reduction, alignment, and preliminary feature extraction. This preliminary action prepares the data for faster subsequent multi-planar and 3D reconstruction, reducing overall processing time while maintaining inspection accuracy.
Solution Approach 2:
The reconstruction algorithms process images from multiple angles in a continuous pipeline rather than sequential steps, maintaining data flow and computational efficiency throughout the reconstruction process. This continuous processing minimizes idle time and ensures that inspection accuracy is achieved without excessive delays.
4Measurement precision
If the x-ray tube current is increased to reduce quantum noise, then image quality is improved, but patient or part exposure to radiation increases
Solution Approach 1:
The system divides the imaging task across multiple x-ray source-detector pairs, each operating at lower current levels. By segmenting the radiation burden across multiple sources, the system achieves the required image quality through combined data while each individual source exposes the part to lower radiation doses, reducing total harmful exposure.
Solution Approach 2:
The system optimizes x-ray tube current parameters for each source-detector pair based on the specific imaging requirements and detected material characteristics. This parameter optimization ensures that the minimum necessary current is used to achieve adequate image quality, thereby minimizing radiation exposure while maintaining measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable characterization of the 3D geometry and dimensional conformity of aeronautical parts with high precision, reducing uncertainties and labor intensity by leveraging a more precise effective model that accounts for actual part geometry and image artifacts.
Implementation Method 1
an x-ray tube to generate x-rays
Implementation Method 2
detectors to measure transmitted x-ray intensity
Data Source
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AI summary
The invention relates to a non-destructive inspection method based on 3D modelling of a part (200), comprising: - using an x-ray device (100) to acquire images of the part at various projection angles (I(n)); - computing projections based on the images acquired at the various projection angles; - in each of multiple iterations: - generating simulated projections corresponding to the computed projections, based on a reference model of an external surface of the part and on a vector µ of transformation parameters of the reference model; - modifying the vector µ with a view to reducing a discrepancy between the simulated projections and the computed projections; - determining a corrected model of the external surface through transformation of the reference model by way of the vector µ resulting from the iterations; - determining an effective model of the part by way of the corrected model.