Continuous X-Ray Tomography Dithering for Artifact Reduction
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Solution Overview
Problem
X-ray microscopy faces challenges such as aberrant detector pixels and variations in source illumination, leading to artifacts in reconstructed images, particularly in continuous motion tomography due to non-ideal sample movements and fixed imperfections in the imaging path.
Innovation Solution
Dithering the sample during scanning by moving it perpendicular to the X-ray beamline between the source and detector, capturing projections, calculating and compensating for non-ideal movements, and performing reconstruction using varying magnification methods to minimize artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous motion tomography is used to reduce motion artifacts and improve imaging speed, then productivity is improved, but artifacts from aberrant detector pixels and fixed imperfections worsen image quality
Solution Approach 1:
The patent applies dithering, which is a form of controlled mechanical vibration, by moving the sample in a small periodic motion during continuous rotation. This vibration prevents stationary artifacts from aberrant detector pixels and fixed imperfections from appearing in the reconstructed image, while maintaining the high imaging speed of continuous motion tomography
2Reliability
If dithering is applied to reduce artifacts from aberrant pixels, then image quality is improved, but device complexity increases due to additional motion control requirements
Solution Approach 1:
The patent merges the dithering motion with the existing continuous rotation motion of the sample. Instead of adding a completely separate dithering mechanism, the system combines small periodic displacements along the beam direction with the ongoing rotational motion, thereby reducing the additional hardware complexity while still achieving artifact reduction
3Measurement precision
If non-ideal sample movements are compensated for during reconstruction, then measurement precision is improved, but device complexity increases due to varying magnification reconstruction requirements
Solution Approach 1:
The patent addresses non-ideal movements by dynamically adjusting reconstruction parameters, specifically varying magnification factors, to account for changes in the effective imaging geometry caused by sample displacement during dithering. This allows accurate reconstruction without requiring complex hardware modifications
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
Reduces the effects of aberrant detector pixels and fixed imperfections, resulting in higher quality images with fewer artifacts and improved resolution in continuous motion tomography.
Implementation Method 1
As the X-ray beam passes through the sample, its intensity is modulated according to the sample's internal structure and composition
Implementation Method 2
dithering the sample during scanning to minimize the effects of aberrant pixels in the detector subsystem and other fixed imperfections in the imaging path
Data Source
AI summary
A method and system for scanning a sample to minimize effects of aberrant detector pixels and fixed imperfections in the imaging path in X-ray microscopy. The method involves moving, i.e., dithering, the sample perpendicular to the X-ray beamline between the source and the detector while capturing projections of the sample, possibly in a continuous fashion. Projection parameters associated with the sample movement, including non-ideal movement of the sample toward and away from the detector, are calculated based on the exact or average position at the time of exposure/trigger. The projections are compensated for the non-ideal movement by changing the geometry description. View angles can be re-estimated and the projections are sorted according to view angle instead of acquisition order. Finally, the reconstruction of the sorted projections is performed using varying magnification reconstruction methods to compensate for the slightly changed geometric magnification.