Photon-Counting Radiation Detector With Boundary Macro Pixel Sizing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing photon counting detectors in radiographic imaging systems experience sensitivity differences between pixels due to varying pixel sizes and high incident photon rates, leading to reduced image quality and inadequate correction methods.
Innovation Solution
Implementing a collimator with walls forming passage holes and grouping subpixels into macro pixels, where pixels near module ends are smaller and follow an arithmetic progression, reducing sensitivity differences by minimizing pixel size variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If pixels in the boundary area are made smaller to maintain pixel pitch continuity, then pixel pitch continuity is improved, but sensitivity difference between pixels increases due to different pixel sizes
Solution Approach 1:
The patent applies local quality by making pixels in the boundary area smaller than pixels in the non-boundary area. This local differentiation maintains pixel pitch continuity at module boundaries while the patent subsequently compensates for the resulting sensitivity differences through signal processing corrections based on pixel size and aperture ratio.
2Measurement precision
If the gap between modules is narrowed to reduce pixel size reduction in the boundary area, then sensitivity difference is reduced, but manufacturing complexity increases due to tolerance design constraints
Solution Approach 1:
The patent changes the parameter of pixel size in the boundary area to be smaller than in the non-boundary area. This parameter change allows the pixel pitch to remain continuous across module boundaries. The patent then compensates for the sensitivity difference caused by this parameter change through signal processing corrections, rather than attempting to eliminate the gap between modules.
3Stability of the object's composition
If correction for output signal is applied depending on pixel size ratio, then pixel pitch continuity is maintained, but sensitivity difference remains inadequate at high incident photon rates
Solution Approach 1:
The patent applies feedback by correcting the output signal based on the pixel size and aperture ratio. The correction amount is determined by the product of pixel size and aperture ratio, which compensates for the sensitivity differences caused by varying pixel sizes. This feedback mechanism ensures uniform sensitivity across all pixels even at high incident photon rates.
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 configuration significantly reduces sensitivity differences between pixels, ensuring uniform sensitivity and improved image quality even at high photon rates, while allowing for practical manufacturing and cost-effective design.
Implementation Method 1
a semiconductor layer that generates electrical charges depending on photon energy of the radiation
Implementation Method 2
a collimator that is disposed between the radiation source and the semiconductor layer, and has a plurality of walls forming a plurality of passage holes through which the radiation passes
Data Source
AI summary
A radiographic imaging apparatus and a radiation detector are provided, which are capable of sufficiently reducing the sensitivity difference between pixels even if the incident photon rate is high. A radiographic imaging apparatus includes: a radiation source for irradiating an object with radiation; a plurality of detection element modules each having a semiconductor layer that generates electrical charges depending on photon energy of the radiation, and a photon counting circuit for counting the electrical charges for each pixel; and a collimator that is disposed between the radiation source and the semiconductor layer, and has a plurality of walls forming a plurality of passage holes through which the radiation passes. A plurality of subpixels is formed on the semiconductor layer, and when one or more subpixels defined by the walls of the collimator are grouped as a macro pixel, a plurality of macro pixels arranged from each end of each of the detection element modules is smaller in size than a macro pixel other than the plurality of macro pixels arranged from the end of the detection element module.