Radiographic Apparatus Parameter Optimization for Computation Speed
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Solution Overview
Problem
Conventional radiographic systems face challenges in speeding up nonlinear optimization operations due to increased computation time as the number of parameters grows, particularly when dealing with high precision tomographic scans and complex structures like Ball Grid Array (BGA) or wiring, where interference and precise positioning requirements increase costs and complexity.
Innovation Solution
A radiographic apparatus and method that includes a parameter calculating device to determine the geometric relationship between radiation emitting and detecting devices using a phantom for correction, and a number of parameters limiting device to reduce the number of parameters calculated by nonlinear optimization, focusing on drive errors and installation inaccuracies, thus speeding up calculations while maintaining convergence accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of parameters is increased to improve measurement precision and convergence accuracy, then the convergence accuracy is improved, but the computation time increases
Solution Approach 1:
The patent dynamically changes the number of parameters to be optimized based on radiographic conditions. When radiographic conditions are stable, fewer parameters are optimized to reduce computation time. When conditions change, the system identifies and optimizes only the necessary parameters, balancing convergence accuracy with computational efficiency.
Solution Approach 2:
The patent applies partial optimization by selecting and optimizing only the most critical parameters rather than all possible parameters. This partial action approach maintains sufficient convergence accuracy while significantly reducing computation time by excluding less influential parameters from the optimization process.
2Measurement precision
If the enlargement ratio is increased to inspect fine structures, then the inspection capability for fine structures is improved, but the interference between X-ray tube and object increases
Solution Approach 1:
The patent transitions from conventional three-dimensional CT scanning to two-dimensional planar CT scanning by restricting the X-ray tube and detector movement to a plane. This dimensional change allows high enlargement ratio imaging without the interference problems of conventional CT, as the X-ray tube and object remain in a planar configuration rather than three-dimensional space.
Solution Approach 2:
The patent uses a phantom for correction that replicates the geometric relationship between the X-ray tube, object, and detector. By scanning the phantom first, the system creates a reference model that can be used to correct and compensate for interference effects during actual object imaging, allowing high enlargement ratio without direct interference.
3Adaptability or versatility
If independent drive mechanisms are used for stage and X-ray detector to enable PCT, then the flexibility and positioning capability are improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges the drive mechanisms of the stage and X-ray detector into a single coordinated system. Instead of independent drives requiring complex synchronization, the system uses a unified control approach where the stage and detector move together in a coordinated manner, reducing overall system complexity while maintaining positioning capability.
Solution Approach 2:
The patent implements feedback control using a phantom for correction. The system scans the phantom, compares the actual scan path with the ideal path, and uses this information to adjust and correct the positioning of both stage and detector. This feedback mechanism simplifies control by automatically compensating for positioning errors rather than requiring complex open-loop control systems.
4Measurement precision
If Bundle Adjustment method is used to calculate parameters, then the measurement precision is improved, but the computation time becomes long
Solution Approach 1:
The patent segments the parameter optimization process into multiple stages. First, the system performs a preliminary scan with the phantom to establish initial parameters. Then, during actual object imaging, the system performs refined optimization only for the most critical parameters. This segmentation reduces the overall computation time while maintaining high measurement precision through multi-stage optimization.
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
The approach significantly reduces computation time for nonlinear optimization operations while ensuring high convergence accuracy by limiting the number of parameters based on radiographic conditions, particularly useful in high enlargement ratio scenarios like planar CT, where drive errors have a greater impact on projection images.
Implementation Method 1
detecting, with a radiation detecting device, radiation emitted from a radiation emitting device and transmitted through an object
Data Source
AI summary
Initial values A^1P^1M^1 . . . A^nP^nM^n of parameters representing a geometric relationship between an X-ray tube, a stage and a flat panel X-ray detector are estimated, a least squares solution (p^W)i of characteristic point three-dimensional coordinates is estimated, and only limited parameters are updated until reprojection square errors converge. Thus, based on known radiographic conditions, initial values of the parameters are estimated, and a nonlinear optimization operation is carried out on only the parameters considered, in view of mechanisms and drive characteristics of the apparatus, to have large errors between the initial values of the parameters and the parameters at a time when radiography is actually carried out. As a result, the calculation can be speeded up, while securing the convergence accuracy of the nonlinear optimization operation, by using the radiographic conditions, i.e. information on tomography.