Straight-Line Trajectory CT Reconstruction
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Solution Overview
Problem
Conventional CT imaging systems face challenges in reconstructing high-quality three-dimensional stereographic images from straight-line trajectory scans, particularly in security inspections, due to limitations in spatial resolution and the need for object rotation or detector rotation, which complicates the scanning of large objects and results in low spatial resolution and sensitivity to data truncation.
Innovation Solution
A system and method that bypasses the rebinning-to-parallel-beam algorithm by applying filtration and back-projection directly to projection data from a straight-line trajectory scan, maintaining higher spatial resolution and reducing the impact of data truncation, allowing for fast stereo imaging without object or detector rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rebinning-to-parallel-beam algorithm is used to reconstruct image from straight-line trajectory scan, then reconstruction can be achieved, but spatial resolution is reduced due to interpolations in angular direction and detector direction
Solution Approach 1:
The patent extracts and eliminates the rebinning interpolation step from the reconstruction pipeline. By directly applying filtered back-projection to the raw straight-line trajectory data without rebining into parallel-beam geometry, the method removes the source of resolution degradation while maintaining reconstruction capability through a modified filtering approach that accounts for the specific geometry of straight-line scanning
Solution Approach 2:
Instead of following the conventional approach of transforming straight-line data into parallel-beam data (rebinning), the patent inverts the logic by directly processing straight-line trajectory data with a customized filtered back-projection algorithm. This inversion eliminates the need for intermediate transformation and its associated interpolation losses
2Adaptability or versatility
If circular cone-beam scan is used for CT imaging, then complete coverage can be achieved, but large cone-angle problem occurs and object rotation is required
Solution Approach 1:
The patent inverts the conventional CT scanning approach by using a straight-line trajectory instead of circular rotation. This inversion eliminates the need for object or detector rotation while achieving sufficient imaging coverage through the linear path, thereby simplifying the scanning operation and avoiding the large cone-angle problem inherent in circular cone-beam geometry
Solution Approach 2:
The patent segments the imaging process into discrete projection measurements taken at multiple positions along the straight-line trajectory. By accumulating projections at different locations rather than requiring continuous rotation, the method achieves comprehensive coverage through a simplified linear scanning sequence that is easier to operate and control
3Productivity
If straight-line trajectory scan is used for fast custom clearance, then scan speed is improved, but three-dimension stereoscopic imaging capability is poor
Solution Approach 1:
The patent changes the reconstruction parameters and filtering approach to be specifically optimized for straight-line trajectory data. By modifying the filtered back-projection algorithm to account for the linear scanning geometry and using appropriate filtering kernels, the method achieves high-quality three-dimensional stereoscopic reconstruction from rapid straight-line scans, thereby improving both scan speed and imaging capability simultaneously
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
The solution improves image spatial resolution and reduces the influence of data truncation, enabling fast and efficient three-dimensional imaging in security inspections, particularly for large objects, while avoiding the need for object or detector rotation.
Implementation Method 1
a radiation source (110), which is an X-ray accelerator, an X-ray tube or a radioisotope source etc.
Implementation Method 2
the detector array (140)... for receiving transmitted signals, to acquire projection data
Data Source
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AI summary
It is disclosed a system and a method for reconstructing an image by using a straight-line trajectory scan to avoid image spatial resolution reduction due to interpolations in angular direction and detector direction during data rebinning. This system comprises: a projection data conversion section for converting projection data from straight-line trajectory scan into projection data under quasi-parallel-beam scan; a filtration section for obtaining filtered projection data by convoluting the projection data under quasi-parallel-beam scan with a predetermined convolutional kernel; and a back-projection section for reconstructing an image by back-projecting the filtered projection data with a weighting factor. By using the inventive system and method, the spatial resolution in the reconstructed image is improved, and the influence of data truncation on the reconstructed image is reduced. The present invention applies the filtration and back-projection mode, and thus has general advantages of the filtration and back projection, such as simplicity and efficiency. And it is easy to be parallelized and accelerated.