Computed Tomography Artifact Reduction via Multi-Position Scanning
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Solution Overview
Problem
Existing Computed Tomography (CT) systems often produce images with artifacts, which are discrepancies between the CT image and the actual material density and geometry of the target, leading to inaccurate representations and hindering quantitative analysis.
Innovation Solution
A CT system is configured to position a target at multiple locations with respect to a radiation beam and detector, acquiring images at these positions to reconstruct CT volume images with reduced artifacts, where the positions are spaced apart from the central axis of the radiation beam, and the magnification at each position is approximately equal, allowing for fewer artifacts in the reconstructed images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing CT systems acquire images using conventional single-position methods, then the system structure is simple, but artifacts occur in the CT images reducing measurement precision
Solution Approach 1:
The patent divides the imaging process into multiple discrete positions (first position, second position, and optionally third position) along the central axis. At each position, a complete set of projection data is acquired independently. This segmentation of the imaging process into multiple positional segments allows artifact reduction through data combination while maintaining relatively simple individual measurement setups.
Solution Approach 2:
The patent introduces the axial dimension (position along the central axis) as a new degree of freedom for data acquisition. Instead of acquiring all data from a single position, the system varies the axial position of the object relative to the radiation source and detector, thereby sampling the object from multiple axial perspectives. This dimensional expansion enables artifact reduction without requiring complex lateral or rotational movements.
2Measurement precision
If multiple positions are used to reduce artifacts, then measurement precision improves, but measurement time increases
Solution Approach 1:
The patent maintains continuous useful action by acquiring complete projection datasets at each axial position without interruption. The radiation source continuously emits beams and the detector continuously records data as the object is positioned at each location. This continuous data acquisition approach at multiple positions maximizes the utility of each measurement interval and enables efficient parallel processing of positional data.
Solution Approach 2:
The system performs preliminary positioning and magnification matching before data acquisition at each position. By pre-establishing the correct geometric relationships and magnification factors for each axial position, the system eliminates the need for complex real-time adjustments during measurement. This preliminary setup enables faster data collection and reduces overall measurement time while maintaining precision.
3Ease of manufacture
If magnification varies at different positions, then positioning is simpler, but manufacturing precision of the imaging system is compromised
Solution Approach 1:
The patent systematically varies the axial position parameter while maintaining constant magnification at each position. By changing only the position parameter along the central axis and compensating to maintain magnification consistency, the system achieves both positioning simplicity and imaging precision. The magnification at each position is controlled to be substantially equal through careful geometric arrangement.
Solution Approach 2:
The patent applies local quality control by ensuring that each axial position is optimized for its specific imaging requirements while maintaining overall system consistency. Each position is configured with appropriate magnification characteristics suited to that specific axial location, allowing local optimization without compromising the global precision of the multi-position system.
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 method reduces the occurrence of artifacts in CT images, enabling more accurate quantitative analysis and dimensional measurements, while also providing a smaller footprint and cost-effective solution compared to existing systems.
Implementation Method 1
The stationary radiation source can be configured to emit a beam of penetrating radiation from a focal point and directed upon a portion of the target. The stationary radiation detector can include a sensing face configured to acquire measurements of an intensity of the radiation beam incident thereon
Data Source
AI summary
A system for computed tomography inspection can include a stage, a stationary radiation source, a stationary radiation detector, and a controller. The stage can secure a target thereon and rotate about a rotation axis. The radiation source can emit a beam of penetrating radiation from a focal point that is directed upon a portion of the target. The radiation detector can include a sensing face configured to acquire measurements of radiation beam intensity incident thereon as a function of position. The controller can command the stage to translate from a first position to a second position in a direction transverse to a central axis of the radiation beam. A magnification of the target at the first and second positions can be approximately equal. The stage does not translate transverse to the central axis of the radiation beam during measurement of the radiation beam intensity by the detector.