X-ray Detector Spatial Response Signature Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Computed radiography (CR) systems face diagnostic image quality loss due to local sensitivity variability in x-ray detectors, which introduces noise and reduces Detective Quantum Efficiency (DQE), making it difficult to discern subtle information and potentially hiding pathology.
Innovation Solution
A method and system for determining the spatial response signature of a photo-stimulable phosphor detector by generating flat field images, applying low-pass filtering, demodulating pixel values, and spatially registering multiple images to minimize angular differences, allowing for the extraction of medium to high spatial frequency components of detector sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple flat field images are processed to determine spatial response signature, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the spatial response signature determination into distinct processing steps: generating multiple flat field images, spatially registering them using reference image selection with minimal angular difference, filtering to extract spatial frequency components, and computing the signature. This segmentation makes the complex measurement process manageable and systematic.
Solution Approach 2:
The patent applies preliminary action by selecting a reference flat field image before spatial registration based on minimal angular difference criteria. This pre-selection optimizes the registration process and improves the accuracy of spatial response signature determination without requiring complex real-time adjustments.
2Manufacturing precision
If spatial warping with reference image selection is applied, then manufacturing precision is improved, but processing time increases
Solution Approach 1:
The patent applies partial action by selecting only the most suitable reference image from multiple flat field images based on angular difference criteria, rather than processing all possible image combinations. This reduces processing time while maintaining sufficient registration accuracy for determining spatial response signature.
3Reliability
If detector sensitivity variability is measured and compensated, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service by enabling the detector system to automatically characterize its own spatial response signature through processing flat field images. This self-characterization capability allows the system to compensate for its own sensitivity variability without requiring external calibration equipment or complex external quality control systems.
4Measurement precision
If medium to high spatial frequency components are extracted, then measurement precision is improved, but loss of information increases
Solution Approach 1:
The patent applies the extraction principle by isolating and analyzing only the medium to high spatial frequency components of the flat field images to determine the spatial response signature. This selective extraction focuses the measurement on the relevant frequency range that characterizes detector sensitivity variability, while low-frequency components are handled separately through spatial registration.
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 improves image quality and DQE by removing detector-related noise, enabling more representative quality control testing and compensating for detector wear, thus enhancing detection capabilities and maintaining image quality over time.
Implementation Method 1
a two dimensional x-ray detector comprising a photostimulable phosphor
Implementation Method 2
scanning the homogeneously exposed detector
Data Source
AI summary
Method and system for determining the spatial response signature of a x-ray detector comprising a photostimulable phosphor by generating a flat field image of the detector, generating a low-pass filtered version of the flat field image and background demodulating the flat field image by pixel-wise dividing it by means of corresponding pixel values in the low-pass filtered version.