CT Calibration Assembly for Geometric Parameter Correction
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Solution Overview
Problem
CT apparatuses, particularly static CT systems with distributed light sources, face significant geometric deviations due to the wide distribution of focal spots, leading to inaccuracies in reconstructed images and spatial resolution, necessitating precise geometric correction.
Innovation Solution
A calibration assembly comprising regularly arranged calibration wires, which are scanned to calculate and correct the positions of centroids, allowing for the optimization of detector parameters and focal spot positions, thereby aligning the coordinate systems across multiple scanning planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a distributed light source is used in static CT apparatus, then scanning speed is improved and noise is reduced, but geometric deviation increases causing target-point position to deviate from design value
Solution Approach 1:
The patent applies preliminary action by performing geometric calibration before actual CT scanning operations. A calibration assembly with known geometric parameters is scanned first to establish reference data, which is then used to correct subsequent scanning measurements. This pre-calibration step compensates for the inherent geometric deviations of distributed light sources without affecting the fast scanning capability.
2Productivity
If multiple scanning planes are used to guarantee angular coverage, then scanning speed is improved, but coordinate system unification becomes complex and geometric correction is required
Solution Approach 1:
The patent implements universality by using a unified calibration assembly that can be scanned across multiple planes to simultaneously calibrate all scanning planes. The calibration assembly contains calibration wires arranged in configurations that allow extraction of geometric parameters for multiple planes from a single scanning process, simplifying coordinate system unification across all planes.
3Adaptability or versatility
If focal spots are widely distributed to achieve multi-plane scanning, then angular coverage is improved, but mechanical error of installation increases causing deformation in reconstructed objects
Solution Approach 1:
The patent replaces mechanical precision requirements with computational correction. Instead of relying on precise mechanical installation of widely distributed focal spots, the system uses a calibration assembly to measure actual positions and applies computational algorithms to correct for installation errors. This substitutes mechanical precision with a combination of measurement and data processing.
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 calibration method effectively corrects geometric errors, improving the spatial resolution and material identification accuracy of CT images by ensuring precise alignment of the X-ray machine and detector positions.
Implementation Method 1
X-ray computed tomography (CT) technology has been widely used in medical and security inspection fields
Data Source
AI summary
Disclosed are calibration assembly and calibration method of calibrating geometric parameters of a CT apparatus. The calibration assembly includes at least one calibration unit each including a plurality of calibration wires, and the plurality of calibration wires are arranged regularly in a same plane. The calibration assembly is easy to be processed and can be used to calibrate geometric parameters of a CT apparatus, and the calibration operations are simple and easy to be implemented.