Radiation Imaging Control Unit Exposure Dose Accuracy
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Solution Overview
Problem
Existing radiation imaging apparatuses face challenges in achieving accurate automatic exposure control (AEC) and automatic brightness control (ABC) due to offset components from dark charges, which reduce the time for X-ray irradiation and delay feedback in high frame rate imaging.
Innovation Solution
A radiation imaging apparatus with a control unit that selects between two methods for radiation exposure control based on imaging conditions, either controlling radiation exposure amount based on detection element signals during irradiation or pixel values in the radiation image, allowing for improved timing and accuracy in radiation exposure management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a preparatory driving sequence is performed to obtain offset components before X-ray irradiation, then measurement precision of exposure dose information is improved, but loss of time for charge accumulation increases
Solution Approach 1:
The patent performs offset component acquisition in advance during a preparatory driving sequence before actual X-ray irradiation. By obtaining the offset components (dark charges and amplifier reference potential) beforehand, the system can subtract these from the pixel outputs during irradiation without interrupting the charge accumulation process, thus resolving the contradiction between measurement precision and time loss.
2Measurement precision
If offset components are obtained immediately before X-ray irradiation, then measurement precision of exposure dose information is improved, but productivity for high frame rate imaging decreases
Solution Approach 1:
The patent acquires offset components during a preparatory driving sequence that occurs before the imaging sequence begins. This preliminary action allows the main imaging sequence to proceed without interruption, maintaining high frame rate productivity while ensuring accurate offset compensation for exposure dose measurement.
3Measurement precision
If ABC analysis result is reflected on next or subsequent frames, then image brightness control accuracy is improved, but loss of time for first frame feedback occurs
Solution Approach 1:
The patent performs ABC analysis on the obtained X-ray image and reflects the analysis result on the next or subsequent frames. While this inherently causes a one-frame delay, the system accepts this trade-off to achieve accurate brightness control, as the alternative would require complex real-time processing that may not be feasible with the available hardware architecture.
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
Enables appropriate control of radiation exposure amount and image brightness, enhancing the efficiency of radiation imaging by reducing delays and improving frame rate capabilities.
Implementation Method 1
a pixel array including a plurality of conversion elements 102 that convert incident radiations or light into charges corresponding to the incident amount
Data Source
AI summary
A radiation imaging apparatus includes an imaging area including a plurality of conversion elements configured to convert a radiation into an electrical signal, a detection element provided in the imaging area and configured to detect the radiation, a reading unit configured to read signals of the conversion elements and the detection element, and a control unit configured to execute radiation exposure amount control in capturing a radiation image by a control method selected from a first control method and a second control method based on an imaging condition in capturing the radiation image, the first control method controlling an exposure amount based on the reading result of the detection element read by the reading unit during radiation irradiation, the second control method controlling the exposure amount based on a pixel value of the radiation image, the radiation image being based on the signals of the plurality of conversion elements.