Radiation Imaging Pixel Segmentation for AEC Timing
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Solution Overview
Problem
Existing radiation imaging apparatuses face challenges in starting image capturing promptly due to the operation of determining correction values for automatic exposure control (AEC), which interferes with the timing of radiation exposure.
Innovation Solution
The implementation of a radiation imaging apparatus with a detection pixel and a correction pixel, where the correction pixel has lower radiation sensitivity, allows for the determination of correction values without interrupting radiation exposure, thereby enabling faster initiation of image capturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction value determination operation is executed before radiation exposure to improve AEC accuracy, then measurement precision is improved, but loss of time increases due to delayed image capturing start
Solution Approach 1:
The patent divides the pixel array into two distinct segments: detection pixels for high-speed radiation dose monitoring and correction pixels for AEC correction value determination. This segmentation allows both functions to operate simultaneously without interfering with each other, resolving the contradiction between maintaining AEC accuracy and avoiding delays in image capturing.
Solution Approach 2:
The correction pixels continuously determine correction values in advance during the reset period before radiation exposure begins. This preliminary action ensures that correction values are ready when needed, eliminating the need to delay image capturing to perform correction value determination.
2Productivity
If detection pixels operate at high speed to monitor radiation dose, then productivity is improved, but measurement precision deteriorates due to inability to accurately measure cumulative dose
Solution Approach 1:
The patent segments the pixel functions by designating specific pixels as detection pixels for high-speed monitoring during irradiation and using correction pixels for accurate cumulative dose measurement. This functional segmentation allows the system to simultaneously achieve high monitoring speed and precise cumulative dose measurement.
Solution Approach 2:
The system implements feedback by using correction pixels to continuously monitor radiation dose and providing correction values to the control unit. This feedback mechanism ensures accurate cumulative dose measurement while maintaining high-speed detection capabilities through the separate detection pixel array.
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 reduces the influence of correction value determination on the timing of image capturing, allowing for more efficient and timely radiation exposure, while maintaining the accuracy of automatic exposure control.
Implementation Method 1
a pixel array including a plurality of pixels arranged in a matrix pattern, each pixel having a photoelectric conversion unit
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
A radiation imaging apparatus (100) executes a correction value determination operation of reading out a signal from a correction value detection pixel once or more in a state where radiation is not emitted onto the apparatus, and determining a correction value that is based on the signal read out from the correction value detection pixel, and a radiation dose determination operation of reading out a signal from a radiation dose detection pixel while radiation is emitted, and determining a dose of radiation that is being emitted, using a value of the signal read out from the radiation dose detection pixel and the correction value. The apparatus executes the correction value determination operation and executes the radiation dose determination operation using the correction value in a case where it is determined that the correction value determination operation is to be executed, and otherwise executes the radiation dose determination operation without executing the correction value determination operation.