Radiation Imaging Pixel Correction via Periodic Remainder Distribution
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Solution Overview
Problem
Radiation imaging apparatuses using flat panel detectors face challenges in accurately correcting radiation signals due to changes in readout circuit characteristics over time, particularly due to temperature changes, which can result in spatial periodicity and affect signal accuracy.
Innovation Solution
The apparatus includes a configuration with multiple types of pixels (imaging, detection, and correction pixels) and a readout circuit with a periodic internal structure, where correction pixels are arranged to have different column number remainders when divided by the circuit's period, allowing for accurate correction of radiation signals by averaging signals from multiple pixel columns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If correction pixels are arranged in a single pixel column, then the device complexity is reduced, but the measurement precision of radiation signal correction deteriorates due to spatial periodicity in readout circuit characteristics
Solution Approach 1:
The pixel array is segmented into multiple pixel columns, each containing correction pixels. By distributing correction pixels across multiple columns with different remainders when divided by the readout circuit period, the system captures diverse readout circuit characteristics, thereby improving correction accuracy while maintaining manageable device complexity
Solution Approach 2:
Different pixel columns are assigned different remainder values (0, 1, 2, ..., period-1) when divided by the readout circuit period. This creates local quality variations in the correction pixel arrangement, ensuring that correction values are obtained from readout circuits with different characteristics, which improves overall correction precision
2Reliability
If correction pixels are read out at different times from imaging pixels, then the readout circuit characteristics may change due to temperature variations, but this temporal separation allows for independent correction signal acquisition
Solution Approach 1:
Correction pixels are read out before imaging pixels during the readout process. This preliminary action allows the system to capture correction signals under initial readout circuit conditions, and subsequent correction values are applied to compensate for characteristic changes that occur during the full readout sequence
Solution Approach 2:
The system uses correction pixels to continuously monitor readout circuit characteristics and generates correction values that are applied to imaging pixel signals. This feedback mechanism compensates for temporal drift in readout circuit characteristics, maintaining correction accuracy despite temperature variations
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 enhances the accuracy of radiation signal correction by accounting for variations in readout circuit characteristics, improving the reliability of radiation imaging by using correction values derived from signals from pixels with diverse characteristics, thereby reducing noise and ensuring precise radiation dose monitoring.
Implementation Method 1
a scintillator 132 and a photodiode 133
Implementation Method 2
a scintillator 132 and a photodiode 133
Data Source
AI summary
A radiation imaging apparatus includes pixels arranged to form pixel rows and pixel columns. The pixels include first pixels and second pixels whose sensitivity to radiation is lower than the first pixels. The apparatus further includes a signal lines arranged to correspond to the pixel columns, a readout circuit configured to read out a signal from the pixels via the signal lines, and a processing unit configured to decide a correction value using signals read out from the second pixels and correct signals read out from the first pixels using the correction value. An internal structure of the readout circuit has a period. The second pixels are arranged such that there are two or more types of remainders of column numbers of pixel columns that include the second pixels divided by the period.