Adaptive Threshold Radiation Detection Controller
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Solution Overview
Problem
Existing radiation imaging apparatuses face errors in detecting the start of radiation irradiation due to noise interference, leading to incorrect determination of radiation onset and subsequent imaging issues.
Innovation Solution
A radiation imaging apparatus with a pixel array and a controller that adjusts the threshold based on measured values from a detector, distinguishing between radiation-induced signals and noise, using adaptive noise level estimation to prevent false detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fixed threshold is used to detect radiation irradiation start, then the detection response is fast, but detection accuracy deteriorates due to noise interference
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed threshold to a dynamic threshold that adapts to changing noise conditions. The threshold is updated based on the standard deviation of detection signals calculated from multiple reference values, allowing the detection system to respond quickly to radiation while adjusting sensitivity based on current noise levels, thus resolving the contradiction between fast response and accurate detection.
Solution Approach 2:
The patent changes the threshold parameter dynamically based on noise characteristics. By calculating the standard deviation from multiple reference values and using this to adjust the threshold, the system maintains fast detection response while improving accuracy under varying noise conditions. This parameter adaptation allows the system to distinguish between noise-induced threshold exceedances and genuine radiation signals.
2Measurement precision
If the threshold is lowered to detect weak radiation signals, then detection sensitivity improves, but false detection due to noise increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the detection signal distribution and using this information to adjust the threshold. The standard deviation is calculated from multiple reference values and fed back into the threshold determination process. This feedback mechanism allows the system to maintain high sensitivity for weak radiation signals while automatically raising the threshold when noise levels increase, thereby reducing false detections.
Solution Approach 2:
The patent applies preliminary action by establishing multiple reference values before actual radiation detection occurs. These reference values are used to calculate the standard deviation and set an initial threshold that accounts for expected noise levels. This preliminary preparation allows the system to distinguish between normal noise variations and genuine radiation signals from the outset, reducing false detections while maintaining sensitivity.
3Reliability
If a high threshold is used to reduce false detection, then reliability improves, but detection speed for weak signals decreases
Solution Approach 1:
The patent resolves this contradiction through dynamic threshold adjustment. Instead of using a permanently high threshold that reduces false detections but slows detection of weak signals, the system dynamically sets the threshold based on current noise conditions. When noise is low, the threshold is lower enabling fast detection of weak signals. When noise is high, the threshold rises to reduce false detections. This dynamic behavior satisfies both requirements simultaneously.
Solution Approach 2:
The patent changes the threshold parameter adaptively based on noise level measurements. By calculating the standard deviation from reference values and adjusting the threshold accordingly, the system maintains high reliability by reducing false detections when noise is present, while preserving fast detection capability for weak radiation signals when noise levels are low. This parameter flexibility resolves the contradiction between reliability and detection speed.
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
Accurately detects the start of radiation irradiation while minimizing errors caused by external noise, ensuring reliable image capture without unnecessary delays or missed imaging opportunities.
Implementation Method 1
a direct method in which radiation is directly converted into an electrical signal
Implementation Method 2
an indirect method in which radiation is converted into light by a scintillator and the light is converted into an electrical signal
Implementation Method 3
a radiation imaging apparatus that detects the start of radiation irradiation based on an electrical signal arising from charges generated in a sensor unit
Data Source
AI summary
A radiation imaging apparatus includes a pixel array having a plurality of pixels configured to detect radiation, a detector configured to detect radiation irradiation, and a controller. In a case in which a measured value obtained by using the detector exceeds a threshold in one range out of a positive range and a negative range with respect to a reference value, the controller controls a radiation image capturing operation by determining that the radiation irradiation has started. The controller changes the threshold in accordance with the measured value of the other range out of the positive range and the negative range.