CT Projection Motion Correction for Low-Cost Artifact Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing CT image reconstruction methods require high computational costs and fail to correct motions such as thermal drifting and focal shift, leading to blurs and streaky artifacts, especially in high-resolution imaging.
Innovation Solution
A method that corrects CT image artifacts by aligning and generating relative motion correction functions using 360° main and reference imaging data, without requiring reconstruction, thus reducing computational costs and correcting motions accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction is performed using reconstructed images, then motion artifacts can be corrected, but calculation cost increases
Solution Approach 1:
The patent applies preliminary action by performing motion correction on projection images before reconstruction. The correction apparatus calculates motion correction values from projection images and applies them to correct the projection images, avoiding the need to perform correction on already-reconstructed images. This preliminary correction approach reduces calculation cost while maintaining correction accuracy.
Solution Approach 2:
The patent extracts the motion correction function from the reconstruction process. Instead of correcting motion artifacts in the reconstructed image domain, the system separates the correction step by extracting motion parameters from projection images and applying corrections in the projection domain, thereby reducing the computational burden of the overall reconstruction process.
2Productivity
If quick scan is performed to reduce motion, then measurement time is reduced, but some motions still remain due to tolerance errors
Solution Approach 1:
The patent implements feedback by calculating motion correction values based on the actual projection images acquired during quick scanning. The system detects motions that occurred during the quick scan by comparing projection images and uses this feedback information to calculate correction values that compensate for tolerance errors and residual motions, thereby maintaining precision despite high imaging speed.
Solution Approach 2:
The patent changes parameters by introducing motion correction values as additional parameters to the imaging process. Instead of relying solely on reducing scan time to minimize motion, the system adjusts the projection images using calculated correction parameters, allowing quick scanning while compensating for residual motions caused by tolerance errors.
3Measurement precision
If sequential estimation of motion is performed, then motion can be corrected, but repetition of projection and backprojection increases calculation cost
Solution Approach 1:
The patent performs motion correction as a preliminary step before reconstruction, calculating motion correction values from projection images and applying them to correct the projection images. This avoids the need for repeated projection and backprojection operations, reducing calculation cost while maintaining correction accuracy.
Solution Approach 2:
The patent replaces the mechanical iteration of projection and backprojection with a more efficient computational approach. Instead of repeatedly performing full projection-backprojection cycles to estimate motion, the system uses a streamlined calculation method that directly computes motion correction values from the projection images, substituting the iterative mechanical process with a more efficient algorithm.
Data Source
AI summary
A system that can reduce the cost for correcting artifacts due to motion in the reconstruction of CT images includes acquiring the temporarily corrected projection image and determining the reference center position correction function and the parameter of the temporary reference center position correction function by calculating a degree of coincidence between the temporarily corrected projection image and the projection image at the imaging angle opposing thereto, and correcting the main imaging data or the projection image based on the main imaging data using the reference center position correction function and the relative motion correction function.