X-Ray Imaging Panel Threshold Correction for Dark-Spot Pixels
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Solution Overview
Problem
Existing X-ray imaging apparatuses face challenges in enhancing image quality without using a higher-powered X-ray source, particularly due to issues with leakage currents and negatively shifted gate-off threshold voltages in thin-film transistors, which affect pixel values and image quality.
Innovation Solution
An X-ray imaging apparatus and control method that include a controller with an image processing unit, detection control unit, and threshold correction unit. The controller generates an inspection image without a subject, detects dark-spot pixels with negatively shifted gate-off threshold voltages, and applies a positive shift voltage to raise the gate-off threshold voltage of the thin-film transistors, thereby correcting the voltage and improving image quality on a per-pixel basis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a higher-powered X-ray source is used to improve image quality, then X-ray emission power is increased, but line artifacts increase and device complexity increases
Solution Approach 1:
The patent changes the electrical parameters of the thin-film transistor by applying a positive shift voltage to raise the gate-off threshold voltage. This parameter change compensates for leakage currents and eliminates the need for higher-powered X-ray sources, thereby avoiding line artifacts while maintaining image quality
Solution Approach 2:
The patent replaces the mechanical/apparatus-based solution (higher-powered X-ray source) with an electrical control solution (threshold voltage correction of TFTs). This substitution eliminates line artifacts while achieving the desired image quality through electrical parameter adjustment rather than increasing X-ray power
2Object-generated harmful factors
If pixel values are corrected by replacing with mean values of adjacent data lines, then line artifacts are reduced, but image quality deteriorates due to loss of original pixel information
Solution Approach 1:
The patent performs preliminary correction by raising the gate-off threshold voltage of thin-film transistors before image acquisition. This preventive action eliminates leakage currents that cause line artifacts, allowing original pixel values to be preserved without requiring post-processing replacement with mean values from adjacent lines
3Device complexity
If thin-film transistors with larger leakage currents are used, then device complexity is reduced, but image quality deteriorates due to dark-spot pixels
Solution Approach 1:
The patent changes the operational parameters of existing thin-film transistors by applying a positive shift voltage to raise their gate-off threshold voltage. This allows the use of simpler thin-film transistor structures with larger leakage currents while maintaining image quality through electrical parameter adjustment rather than requiring complex low-leakage transistor designs
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 enhances image quality without requiring a higher-powered X-ray source by correcting the gate-off threshold voltage of thin-film transistors, reducing leakage currents and improving pixel values, thus addressing the issue of dark-spot pixels and enhancing overall image quality.
Implementation Method 1
a scintillator that converts X rays emitted from the X-ray source into light
Implementation Method 2
a photoelectric conversion element that converts the light from the scintillator into an electrical signal
Data Source
AI summary
An X-ray imaging apparatus includes an X-ray source, an X-ray imaging panel, and a controller. The controller includes an image processing unit that generates an inspection image in accordance with a data signal read from a thin-film transistor with the thin-film transistor supplied with a gate signal, a detection control unit that detects a dark-spot pixel from the inspection image, and a threshold correction unit that applies, to a gate of the thin-film transistor corresponding to the dark-spot pixel, a positive shift voltage that raises a gate-off threshold voltage of the thin-film transistor.