CT Scanner Rotation Angle Correction via Timestamp Interpolation
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Solution Overview
Problem
Computed tomography (CT) scanners face errors in recording projection acquisition times due to system errors, leading to inaccuracies in determining rotation angles, which result in artifacts in reconstructed images.
Innovation Solution
A method and system that modify recorded projection acquisition times using a linear interpolation algorithm to determine new rotation angles, reducing errors and improving image reconstruction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the CT scanner records projection acquisition times directly from hardware, then the recording process is simple and fast, but system errors cause errors in the recorded times leading to inaccurate rotation angles
Solution Approach 1:
The patent introduces an intermediary processing system that receives hardware timestamp data and applies software-based correction algorithms. A processor acts as a mediator between the hardware timestamp generator and the rotation angle calculation system, using reference timestamps and interpolation algorithms to correct systematic errors without modifying the original hardware recording mechanism.
Solution Approach 2:
The system performs preliminary correction of timestamp errors before rotation angle calculation. By establishing reference timestamps at known gantry positions and pre-calculating correction factors, the system prepares corrected time data in advance, ensuring accurate rotation angles without requiring complex real-time hardware modifications during scanning.
2Productivity
If the system uses hardware timestamp recording, then the data acquisition is efficient, but systematic errors cause artifacts in reconstructed images
Solution Approach 1:
The system implements a feedback mechanism where reference timestamps taken at known gantry positions are used to detect systematic errors in hardware recording. The detected errors generate correction factors that are applied to all projection timestamps, creating a closed-loop error compensation system that eliminates artifacts while maintaining acquisition efficiency.
Solution Approach 2:
The patent transforms the timestamp parameter from raw hardware values to corrected values through mathematical transformation. By applying correction factors derived from reference measurements, the system changes the timestamp parameter to compensate for systematic hardware errors, thereby eliminating the harmful effects without slowing down data acquisition.
3Measurement precision
If correction algorithms are applied to timestamp data, then rotation angle accuracy improves, but processing complexity increases
Solution Approach 1:
The system applies correction algorithms selectively to reference timestamps rather than all projection data. By performing partial correction on a subset of known-good reference points, the system derives correction factors that are then applied to all data, reducing processing complexity while maintaining high rotation angle accuracy across the entire dataset.
Data Source
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AI summary
Systems and methods for determining rotation angles are disclosed. The systems may perform the methods to: obtain a rotation speed of a radioactive scanning source(115) in a CT scanner(110); obtain a plurality of original projection acquisition times corresponding to a plurality of projection samples, the plurality of projection samples being associated with rotation of the radioactive scanning source(115); determine a plurality of original rotation angles corresponding to the plurality of projection samples based on the plurality of original projection acquisition times and the rotation speed of the radioactive scanning source(115); and determine a plurality of modified rotation angles corresponding to the plurality of projection samples by modifying the plurality of original rotation angles.