Tomographic Reconstruction of Moving Objects via Motion-Aware Compression
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Solution Overview
Problem
Current tomographic reconstruction methods for moving objects are degraded due to incomplete projection data and motion artifacts, leading to suboptimal 3D image reconstruction when the object is in motion, as they either average motion or require excessive X-ray doses and longer acquisition times.
Innovation Solution
A method that processes a sequence of 2D projection images using a medical imaging system, incorporating a function that balances fidelity, spatial and temporal compression, and an approximate motion model, with a decreasing sequence of compressibility parameters to reconstruct a sequence of 3D images, leveraging prior knowledge of motion for improved reconstruction quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the object is in motion during tomographic acquisition, then the reconstruction quality is degraded due to motion artifacts and incomplete projection data, but increasing the number of projections and acquisition angles would require excessive X-ray doses and longer acquisition times
Solution Approach 1:
The patent applies preliminary action by using prior knowledge of the object's motion trajectory to guide the reconstruction process. The motion model is established before reconstruction, allowing the system to anticipate and compensate for motion effects, thereby achieving accurate 3D reconstruction without requiring excessive projection data or X-ray doses.
Solution Approach 2:
The patent implements feedback by iteratively refining the reconstruction based on the motion model and projection data. The system uses the motion information to adjust and optimize the reconstruction process, continuously improving the 3D image quality while minimizing the required X-ray dose and acquisition time.
2Measurement precision
If the object is in motion during tomographic acquisition, then the reconstruction quality is degraded, but increasing the number of projections and acquisition angles would prolong the acquisition time
Solution Approach 1:
The patent applies preliminary action by establishing the motion model before the reconstruction process. This prior knowledge of motion allows the system to efficiently process the projection data without needing to acquire additional projections or extend the acquisition time, thereby maintaining high reconstruction quality while reducing acquisition time.
Solution Approach 2:
The patent implements feedback by using the motion model to iteratively optimize the reconstruction process. This feedback mechanism allows the system to achieve accurate 3D reconstruction faster by leveraging the pre-established motion information, reducing the need for extended acquisition time.
3Measurement precision
If motion compensation is performed by integrating a sequence of operators, then reconstruction accuracy improves, but the complexity of the processing increases
Solution Approach 1:
The patent applies parameter changes by using a deformable model that adapts to the object's motion through a set of parameters describing the motion trajectory. This approach simplifies the processing complexity compared to integrating full sequence of operators, as it uses a compact parameter representation to achieve accurate motion compensation and reconstruction.
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
This approach enables accurate 3D reconstruction of moving objects by minimizing reconstruction errors and reducing the need for excessive X-ray doses and prolonged acquisition times, providing a balanced trade-off between reconstruction quality and computational efficiency.
Implementation Method 1
The emission of X-rays 10 from a source towards the organ 12, the X-rays being emitted at different angles lε{1, . . . , L}
Data Source
AI summary
A method is provided for processing a sequence of sets of 2D projection images of a moving object, wherein the sequence of sets of 2D projection images is obtained by a medical imaging system that is in motion along a trajectory. The method comprises determining a sequence of images which minimize a function dependant on a set of 3D images, a term of fidelity of the sequence of images, a function of spatial and temporal compression of the sequence of images, a compressibility parameter, and a sequence of operators for an approximate modelling of motion. The sequence of operators leads to a compression constraint augmented by partial knowledge of the motion and the minimization comprises defining a decreasing sequence of degrees of compressibility for which an estimation is determined from an initial sequence.