Counting X-ray Detector Missing Pixel Interpolation
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Solution Overview
Problem
Counting X-ray detectors face challenges in achieving high-quality images due to their modular structure, which results in discontinuities, reduced efficiency at the edges, and increased noise, particularly because of missing pixels and the limited active surface area of edge pixels, leading to suboptimal signal-to-noise ratios.
Innovation Solution
A method for generating X-ray images using a counting X-ray detector with a uniform matrix structure, where missing pixels are corrected by interpolating and extrapolating signal data from surrounding pixels, and adjusting signal responses to achieve uniformity, thereby improving image quality and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a modular structure with multiple detector modules is used to achieve large surface area, then the detector can cover a larger area, but discontinuities and missing pixels occur at the edges and joints
Solution Approach 1:
The detector is divided into multiple detector modules that can be arranged in different configurations (one-dimensional array, two-dimensional array, or radial arrangement around the isocenter) to achieve the required large surface area while maintaining manageable module sizes for fabrication
Solution Approach 2:
Different correction strategies are applied to different regions: edge pixels receive specific correction for their reduced active surface area, missing pixels are reconstructed using interpolation from surrounding pixels, and the correction factors are position-dependent to account for local variations in the modular structure
2Area of stationary object
If detector modules are arranged adjacently to form a uniform matrix, then coverage area increases, but edge pixels have reduced active surface area leading to lower signal-to-noise ratio
Solution Approach 1:
Position-dependent correction factors are calculated and applied specifically to edge pixels to compensate for their reduced active surface area. The correction takes into account the specific geometric location of each pixel relative to module boundaries, restoring the signal-to-noise ratio to match that of central pixels
Solution Approach 2:
The correction factors are determined as a function of position parameters (distance from module edges, angle relative to isocenter for radial arrangements), allowing the system to adapt the signal correction dynamically based on the pixel's location within the modular detector array
3Ease of manufacture
If missing pixels are present in the detector matrix, then module assembly becomes feasible, but image quality deteriorates due to gaps in image data
Solution Approach 1:
Missing pixel values are reconstructed by creating copies of data from surrounding existing pixels through interpolation algorithms. The signal from neighboring pixels is combined and weighted to generate estimated values for the missing positions, effectively copying and reconstructing the image information that would have been captured by the missing pixels
Solution Approach 2:
Correction factors for missing pixels are pre-calculated based on the known detector geometry and module arrangement. During image acquisition, these pre-computed factors are applied to rapidly reconstruct the missing data without requiring complex real-time processing
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 results in improved image quality by correcting for design-related errors and enhancing signal-to-noise ratios, providing a more accurate and detailed X-ray image despite the modular structure's limitations.
Implementation Method 1
X-ray radiation is converted in the direct converter (e.g., CdTe or CZT), and the generated charge carrier pairs are separated via an electrical field
Implementation Method 2
the generated charge carrier pairs are separated via an electrical field that is generated by a common top electrode and a pixel electrode
Data Source
AI summary
Generation of an X-ray image of an object using a counting X-ray detector is provided. The X-ray detector includes detector modules that may be aligned adjacent to one another. Each of the detector modules is subdivided into a matrix having a plurality of pixels. The detector modules are arranged adjacent to one another on a common substrate. A sensor surface formed by the detector modules has a uniform matrix structure having a constant pixel pitch. At least one missing pixel is arranged within the sensor surface. Raw image data is acquired by a portion of the detector modules of the X-ray detector, the acquired raw image data is at least partially corrected, and further raw image data is calculated for the at least one missing pixel using the corrected raw image data. The X-ray image is calculated based on the corrected raw image data and the further raw image data.