Radiation Imaging Pixel Gain Adjustment for Signal Balance
Solution Overview
Problem
Current radiation imaging apparatuses face challenges in obtaining high-quality images of fast-moving subjects using the energy subtraction method due to signal value imbalances between sub-images, leading to reduced accuracy and potential output saturation.
Innovation Solution
A radiation imaging apparatus with a pixel array and processing circuit that samples and holds electrical signals at different gain settings during radiation irradiation, allowing for differential sensitivity adjustments to balance signal values and prevent saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the tube voltage is changed between imaging to obtain different energy sub-images, then energy subtraction capability is improved, but signal value imbalance occurs between sub-images leading to reduced accuracy
Solution Approach 1:
The processing circuit dynamically adjusts the gain of the conversion element based on the radiation energy level. When tube voltage is changed between imaging, the gain is adjusted in real-time to maintain balanced signal values, preventing the signal imbalance that would otherwise occur with fixed gain settings.
Solution Approach 2:
The gain parameter of the conversion element is changed according to the radiation energy level. By adjusting the gain parameter dynamically based on the tube voltage setting, the system maintains optimal signal levels for energy subtraction imaging while preventing both signal loss and saturation.
2Measurement precision
If high gain is used to amplify weak signals, then signal strength is improved, but output saturation occurs for strong signals
Solution Approach 1:
The gain of the conversion element is dynamically adjusted based on the signal strength and radiation energy level. The system automatically selects appropriate gain levels to prevent both signal saturation and excessive noise amplification, ensuring reliable imaging across different conditions.
Solution Approach 2:
The processing circuit monitors signal levels and adjusts the gain accordingly. When signal strength indicates potential saturation, the gain is reduced; when signals are weak, the gain is increased. This feedback mechanism ensures optimal signal quality without saturation.
3Reliability
If low gain is used to prevent saturation, then output saturation is prevented, but signal strength becomes too weak for accurate processing
Solution Approach 1:
The gain setting is dynamically optimized based on the detected signal characteristics and radiation energy level. The system selects the highest possible gain that prevents saturation while maintaining sufficient signal strength for accurate processing, adapting to each imaging condition in real-time.
Solution Approach 2:
The gain parameter is adjusted to match the signal intensity and energy level. By optimizing the gain parameter for each imaging condition, the system ensures signals are amplified sufficiently for processing while remaining below saturation thresholds.
4Measurement precision
If multiple images are captured at different energy levels, then energy subtraction quality is improved, but imaging time increases reducing productivity
Solution Approach 1:
The imaging process continues without interruption as the conversion element and processing circuit operate continuously to capture multiple energy levels. The gain adjustment occurs during the imaging process itself, eliminating the need for separate acquisition steps and maintaining continuous productive imaging.
Solution Approach 2:
The tube voltage and gain parameters are changed during the imaging process to capture multiple energy sub-images sequentially. This allows the system to obtain the necessary data for energy subtraction without requiring separate imaging sessions, maintaining productivity while improving quality.
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 enables the acquisition of radiation images with improved quality by adjusting sensitivity settings to balance signal values, enhancing the accuracy of energy subtraction and preventing output saturation.
Implementation Method 1
a conversion element configured to convert radiation into an electrical signal
Data Source
AI summary
A radiation imaging apparatus includes an imaging unit having a plurality of pixels. Each of the plurality of pixels includes a conversion element configured to convert radiation into an electrical signal, a processing circuit configured to process the electrical signal output from the conversion element, and a holding unit configured to sample and hold the electrical signal output from the processing circuit. After radiation irradiation from a radiation source is started and before next radiation irradiation from the radiation source is started, the holding unit samples and holds, at a first timing and a second timing which is after the first timing, the electrical signal output from the processing circuit. A gain of the processing circuit at the first timing and the gain of the processing circuit at the second timing are different from each other.