CT Image Compensation via Non-Rigid Registration
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Solution Overview
Problem
Inconsistent images generated during X-ray CT scanning due to patient movement disrupt image continuity, affecting medical diagnosis.
Innovation Solution
An image compensation method using a three-dimensional non-rigid registration technique to calculate overlapping positions and transformational matrices, allowing for image alignment and compensation to achieve consistent images across scanning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If step-scan mode is used to increase rotational speed and spatial resolution, then scanning efficiency is improved, but patient movement causes image inconsistency between adjacent scannings
Solution Approach 1:
The patent applies preliminary action by calculating the overlapping position between adjacent scannings before image reconstruction. The system determines the overlap region in advance, then performs non-rigid registration on images within this overlap region to establish transformation matrices that compensate for patient movement, ensuring image consistency before final reconstruction.
Solution Approach 2:
The patent changes parameters by introducing a transformation matrix that modifies image coordinates based on calculated deformation fields. The non-rigid registration method adjusts spatial parameters of images in the overlapping region, transforming them to match the reference scanning's coordinate system, thereby resolving inconsistency caused by patient movement.
2Measurement precision
If three dimensional non-rigid registration method is applied to calculate transformational matrices, then image alignment accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the image processing into distinct stages: first identifying the overlapping region between adjacent scannings, then performing non-rigid registration only on this segmented overlap region, and finally applying the transformation to the complete image set. This segmentation reduces computational complexity compared to processing entire volumes.
Solution Approach 2:
The patent uses an intermediary approach by introducing a transformation matrix as a mediator between the floating image and reference image. The non-rigid registration calculates deformation fields that populate this matrix, which then serves as an intermediary transformation tool to align images without requiring direct complex point-to-point correspondence calculations.
Data Source
AI summary
A method and apparatus of image compensation are provided. The method may include: calculating an overlapping position between two adjacent scannings; obtaining two images at the overlapping position of the two adjacent scannings, and calculating mutual information of the two images by using a three dimensional non-rigid registration method; and acquiring a corresponding transformational matrix when the mutual information reaches a threshold, and compensating one of the two scans which needs to be compensated by using the transformational matrix. Images at the overlapping position of two neighboring scannings can be used to find a motion law at an identical z position of the two adjacent scannings and to obtain a corresponding match factor. Thus inconsistence of images caused by a patient's movement can be compensated.