Dual-Gain Pixel Charge Readout for Low-Noise X-Ray Imaging
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Solution Overview
Problem
Existing radiological imaging systems face challenges in reducing noise across a wide range of X-ray signal levels, requiring multiple image processing platforms tailored to specific applications, which limits the use of a single platform for various X-ray applications.
Innovation Solution
A system and method that perform low-gain and high-gain measurements using feedback capacitors in a digital X-ray system, allowing for adaptable noise reduction techniques to be applied across different X-ray applications by redistributing charge between capacitors and adjusting integrator gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-gain measurement is used to reduce electronic noise in low X-ray energy applications, then electronic noise is reduced, but the system cannot handle high X-ray energy applications with high dynamic range requirements
Solution Approach 1:
The integrator gain is made dynamically adjustable through switching between different feedback capacitor configurations. The system transitions from a static gain architecture to a dynamic one where the gain can be changed based on the X-ray application requirements, allowing the same hardware to adapt to both low-energy fluoroscopy and high-energy radiography/mammography applications
Solution Approach 2:
The feedback capacitor value is changed as a parameter adjustment to modify the integrator gain. By switching between different capacitor values (C1 and C2), the system changes the gain parameter to match the specific application needs, enabling a single platform to handle varying signal levels and noise characteristics across different X-ray applications
2Measurement precision
If multiple image processing platforms are developed for different X-ray applications, then each application gets optimized noise reduction, but device complexity and development cost increase
Solution Approach 1:
A single image processing platform is designed to perform multiple functions by incorporating adjustable integrator gain capability. The system can serve fluoroscopy, radiography, and mammography applications within one platform, eliminating the need for separate dedicated systems for each application while maintaining optimized noise reduction performance for each specific use case
Solution Approach 2:
The feedback capacitor is divided into multiple segments (C1 and C2) that can be independently switched into the circuit. This segmentation allows the system to select different capacitor values based on application requirements, providing multiple operating modes within a single platform rather than requiring separate systems
3Adaptability or versatility
If low-gain measurement is used for high X-ray energy applications, then dynamic range is maintained, but electronic noise dominates the noise floor in low energy applications
Solution Approach 1:
The system dynamically adjusts the integrator gain based on the X-ray application. For low-energy fluoroscopy applications, the gain is increased by switching to a smaller feedback capacitor value, thereby reducing electronic noise dominance. For high-energy applications, the gain is kept lower to maintain dynamic range, demonstrating adaptive behavior to different operating conditions
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
Enables low-noise measurements for a wide range of analog signal strengths, improving image quality and enabling lower dose protocols while allowing a single image processing platform to be used across various X-ray applications.
Implementation Method 1
the input pixel charge is distributed to two feedback capacitors, which together provide a relatively low integrator gain. After the low-gain measurement, a high-gain measurement is performed, wherein one of the capacitors is removed from the feedback loop and the charge is redistributed to the remaining capacitor
Data Source
AI summary
According to embodiments of the present technique, a system and a method for obtaining low-noise measurements for a wide range of analog signal strengths is provided. According to aspects of the present technique, a low-gain measurement of an input pixel charge is performed, wherein the input pixel charge is distributed to two feedback capacitors, which together provide a relatively low integrator gain. After the low-gain measurement, a high-gain measurement is performed, wherein one of the capacitors is remove from the feedback loop and the charge is redistributed to the remaining capacitor.