Digital X-ray Detector Dark Correction via Offset Adjustment Map
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Solution Overview
Problem
Portable, battery-operated digital radiography detectors face challenges in maintaining image quality due to power mode transitions and uneven temperature profiles, which affect dark correction and lead to imaging anomalies, especially in unpredictable operating conditions.
Innovation Solution
A method for forming an offset-corrected exposure image involves obtaining an initial exposure image, associated metadata, and using stored dark image data to create an offset adjustment map, which is combined with the exposure image to correct for offset variations, adapting to power mode transitions and temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic dark calibration is performed to compensate for temperature drifts, then image quality is improved, but device complexity and processing time increase
Solution Approach 1:
The patent performs dark calibration at specific predetermined intervals (e.g., after warm-up period, periodically thereafter) rather than continuously. This preliminary action at key moments compensates for temperature drifts without requiring constant processing, reducing overall system complexity while maintaining image quality.
Solution Approach 2:
The system implements periodic dark calibration cycles at predetermined intervals during operation. This periodic action allows the detector to compensate for temperature drifts at regular intervals without continuous processing, balancing image quality maintenance with reduced processing complexity.
2Measurement precision
If dark images are captured frequently for offset correction, then measurement precision is improved, but energy consumption increases
Solution Approach 1:
The patent captures dark images at specific predetermined intervals (e.g., after warm-up, periodically) rather than continuously. This preliminary action at key moments provides sufficient offset correction data without requiring constant dark image capture, thereby reducing energy consumption while maintaining measurement precision.
Solution Approach 2:
The system uses the detector's own dark signal output for calibration purposes. By capturing dark images and using them for offset correction, the system self-calibrates without requiring external reference sources or additional dedicated calibration components, reducing overall energy requirements.
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 provides automatic correction for offset signal variations in portable DR detectors, improving image quality and battery life by minimizing the impact of power cycling and temperature-related issues, ensuring diagnostic-quality images in varying conditions.
Implementation Method 1
A scintillator 14 has a material, such as gadolinium oxisulfide, Gd2O2S:Tb (GOS) or cesium iodide, that absorbs x-rays incident thereto and converts the x-ray energy to visible light photons
Implementation Method 2
The light sensitive components of the a-Si:H pixels convert the incident light into electrical charge which is stored in the internal capacitance of pixel 24
Data Source
AI summary
A method of forming an offset-corrected exposure image includes obtaining an initial exposure image and exposure metadata related to the initial exposure image. An intermediate offset-corrected exposure image is formed by obtaining one or more dark images associated with the initial exposure image and subtracting an averaged value of the one or more dark images from the initial exposure image. The offset-corrected exposure image is obtained by combining an offset adjustment map with the intermediate offset-corrected exposure image.