Radiation Detector Grid-Stripe Filtering for Accurate AEC
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Solution Overview
Problem
The accuracy of Automatic Exposure Control (AEC) in radiation imaging apparatuses is compromised by scattering rays generated within the subject, which cause variations in signal detection due to the presence of a scattering ray removing grid, leading to reduced precision in dose measurement.
Innovation Solution
A radiation imaging apparatus with a configuration that includes detecting pixels to monitor radiation dose, a reducing unit to mitigate the frequency component of grid stripes, and a calibration unit to adjust detection values, allowing for independent control of imaging and detecting pixels, thereby enhancing AEC accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a scattering ray removing grid is placed between the subject and the FPD, then scattering ray reduction is improved, but measurement precision deteriorates due to signal amount differences caused by overlapping radiation shielding materials
Solution Approach 1:
The patent extracts and removes the frequency component corresponding to grid stripes from the detection signal. By identifying and extracting this specific frequency component caused by the grid's radiation shielding materials, the system eliminates the harmful interference while preserving the accurate radiation dose measurement signal.
Solution Approach 2:
The patent introduces an intermediary signal processing step that acts as a mediator between the raw detection signal and the final AEC calculation. This intermediary process uses frequency domain filtering to separate the grid-induced artifacts from the genuine radiation signal, enabling accurate measurement despite the presence of the grid.
2Measurement precision
If the arrangement period of detecting pixels is made different from the grid's radiation shielding material, then grid stripe interference is reduced, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical approach of physically arranging pixels at non-coincident intervals with a signal processing approach. Instead of complicating the hardware pixel layout, the system uses frequency domain filtering in the signal processing stage to achieve the same goal of eliminating grid stripe interference, thereby maintaining simple device architecture while improving measurement precision.
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
The solution effectively reduces the impact of grid stripes on detection values, ensuring accurate dose measurement and enabling precise control of radiation exposure, thus improving the overall accuracy of AEC.
Implementation Method 1
a radiation detector including a plurality of pixels configured to convert radiation into electrical signals
Data Source
AI summary
A radiation imaging apparatus comprises a radiation detector including a plurality of pixels configured to convert radiation into electrical signals, one or more of the plurality of pixels being configured to operate as a detecting pixel for detecting irradiation amounts of the radiation. The radiation imaging apparatus reduces a frequency component relating to grid stripes produced by a scattering ray removing grid included in detection values for the irradiation amounts of the radiation obtained from the plurality of detecting pixels forming a detecting pixel group.