X-ray Imaging Apparatus Scanning Control for Artifact Reduction
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Solution Overview
Problem
High-speed radiation imaging modes in digital X-ray systems using large-area flat panel sensors face issues with image artifacts due to power supply voltage fluctuations during resetting operations, which disrupt analog signal outputs and result in distorted moving images.
Innovation Solution
The implementation of a control method that synchronizes the scanning and exposure operations with the imaging unit control circuit, allowing for intermittent radiation pulsing and temporary cessation of shift register scanning to stabilize power supply voltage, enabling accurate offset correction and reducing artifacts through fixed pattern noise image acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If resetting operation is performed during analog signal scan in high-speed imaging mode, then frame rate is improved, but power supply voltage fluctuates causing artifacts in moving image
Solution Approach 1:
The patent divides the imaging process into distinct phases: a first scanning period where shift registers output analog signals, and a second scanning period where resetting operation is performed. This temporal segmentation prevents simultaneous operation of scanning and resetting, eliminating power supply voltage fluctuations during signal output and thereby removing artifacts from the moving image while maintaining high frame rate capability.
2Productivity
If sum of scanning time and accumulation time is larger than imaging interval, then high-speed imaging is achieved, but resetting operation during output period causes voltage fluctuation
Solution Approach 1:
The patent dynamically adjusts the scanning process by implementing two distinct scanning periods with different functions. The first scanning period outputs analog signals for image acquisition, while the second scanning period performs resetting operation. This dynamic reconfiguration of scanning timing allows the system to achieve high imaging speed by overlapping accumulation time with the first scanning period, while preventing voltage fluctuations during the critical signal output phase.
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 effectively minimizes image artifacts in high-speed imaging modes by stabilizing power supply voltage and allowing for precise offset correction, resulting in high-quality radiation images.
Implementation Method 1
a large-area flat panel sensor formed by two-dimensionally joining photoelectric conversion elements generated on a silicon semiconductor wafer
Data Source
Figure 1
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AI summary
A radiation imaging apparatus comprises: output means (202,203) for outputting an analog signal for each pixel circuit by sampling and holding an electrical signal converted from radiation; and selection means (131-138, 108) for sequentially selecting positions of pixel circuits which output the analog signals, wherein after the output means outputs the electrical signals corresponding to a predetermined number of pixel circuits as analog signals, the selection means stops the selection and the output means stops the output in accordance with the stop of the selection.