X-Ray CT Motion Estimation for Body-Axis Image Continuity
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Solution Overview
Problem
Existing X-ray CT systems face challenges in maintaining image continuity, particularly in the body axis direction, during asynchronous imaging due to high computational costs and reduced motion correction accuracy, and are dependent on image reconstruction conditions.
Innovation Solution
A motion estimation model with independently adjustable regularization terms for spatial and temporal continuity is introduced, allowing dynamic adjustment to image reconstruction conditions, using a free-form deformation model based on a 3D B-spline function for motion correction reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple PAR image pairs are used for reconstructing one cross section to prevent deterioration of continuity, then image continuity is improved, but computational cost increases
Solution Approach 1:
The patent extracts and applies motion correction information from only one PAR image pair per cross section, rather than using multiple pairs. This selective approach maintains image continuity while significantly reducing computational cost by eliminating redundant calculations from additional PAR image pairs.
Solution Approach 2:
The patent applies partial action by using motion correction information from a single PAR image pair, which is sufficient to achieve the desired image continuity. This avoids the excessive computation that would result from processing multiple PAR image pairs, while still obtaining adequate motion correction效果.
2Speed
If table speed is increased to achieve faster scanning, then scanning speed is improved, but motion correction accuracy is reduced due to reduced data amount
Solution Approach 1:
The patent replaces the mechanical approach of increasing data collection (slower scanning) with a computational approach. By applying motion correction algorithms that can accurately estimate motion from limited data, the system achieves both fast scanning speed and maintained motion correction accuracy without being constrained by data quantity.
3Adaptability or versatility
If image reconstruction conditions are changed to adapt to different imaging positions, then adaptability is improved, but motion correction accuracy becomes dependent on reconstruction conditions
Solution Approach 1:
The patent implements dynamic adjustment of motion correction parameters based on reconstruction conditions. The system adapts its motion correction approach according to the specific imaging scenario, maintaining accuracy across varying reconstruction conditions by dynamically optimizing the correction process rather than using fixed parameters.
Solution Approach 2:
The patent changes key parameters of the motion correction process based on reconstruction conditions. By adjusting parameters such as regularization weights and optimization settings according to the specific imaging scenario, the system maintains motion correction accuracy across different reconstruction conditions while preserving adaptability.
Data Source
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AI summary
Provided is an X-ray CT apparatus (1) capable of preventing excessive motion correction or deformation, particularly maintaining continuity of images in a body axis direction, and performing motion correction reconstruction under an optimal condition according to an image reconstruction condition, in motion correction reconstruction. A processor (200) for image processing of an X-ray CT apparatus (1) according to the present invention includes a motion estimation model including regularization terms that are independently adjustable for continuity of a spatial domain and continuity of a time domain, as a motion estimation model for acquiring motion information. The motion estimation model is configured to adjust a weight of the regularization term and a control point position. A motion information acquisition unit automatically adjusts the motion estimation model or a calculation method of a control point parameter using the motion estimation model according to a FOV or an image reconstruction interval which is an image reconstruction condition. As a result, it is possible to satisfactorily maintain image continuity in one cross section and inter-slice image continuity in a body axis direction.