Radiographic Offset Correction for Image Lag and Random Noise
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Solution Overview
Problem
Existing radiographic imaging technologies face challenges in accurately correcting offset components due to residual electric charges and dark current, leading to image lag and random noise, particularly in methods that either fail to correct image lag sufficiently or increase random noise.
Innovation Solution
A radiographic imaging apparatus that alternately acquires radiation and offset images, performing offset correction using a plurality of offset images when the change between them is below a threshold, combining intermittent and averaging techniques to reduce both image lag and random noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fixed offset correction method is used (subtracting non-exposure image acquired before radiation image), then random noise is reduced, but image lag cannot be sufficiently corrected
Solution Approach 1:
The patent applies dynamics by making the offset correction method adaptive rather than fixed. The system dynamically selects between fixed offset correction and intermittent offset correction based on real-time evaluation of image quality metrics (image lag and random noise levels). This dynamic adaptation allows the system to optimize correction accuracy for each specific imaging condition, resolving the contradiction between reducing random noise and correcting image lag effectively.
Solution Approach 2:
The patent changes the parameter of offset correction timing and method based on imaging conditions. By evaluating image lag and random noise characteristics, the system adjusts whether to use pre-acquired offset images (fixed method) or interleaved offset images (intermittent method). This parameter change enables the system to achieve both low random noise and accurate image lag correction by selecting the appropriate correction approach for each scenario.
2Measurement precision
If intermittent offset correction method is used (alternately capturing radiation image and non-exposure image), then image lag is reduced, but random noise increases
Solution Approach 1:
The system dynamically evaluates whether intermittent offset correction is necessary by measuring image lag levels. When image lag is significant, the system switches to intermittent correction mode to achieve accurate lag removal. When image lag is minimal, the system transitions to fixed offset correction to minimize random noise. This dynamic decision-making resolves the contradiction by applying intermittent correction only when truly needed.
Solution Approach 2:
The patent changes the offset correction strategy parameter based on detected image characteristics. By monitoring image lag magnitude, the system adjusts the correction method: using intermittent correction (one offset image per radiation image) when lag is high, and fixed correction (averaged offset images) when lag is low. This parameter adaptation allows the system to minimize random noise while maintaining adequate image lag correction.
3Object-affected harmful factors
If offset images are acquired before radiation image, then random noise is reduced through averaging, but accuracy of offset correction deteriorates due to temperature changes and time degradation
Solution Approach 1:
The patent applies preliminary action by acquiring multiple offset images before radiation imaging when conditions are stable (low temperature variation, short time intervals). This preliminary acquisition allows averaging to reduce random noise while the offset characteristics still accurately represent the subsequent radiation image conditions. The system evaluates whether preliminary offset images remain valid based on temperature and time criteria, ensuring correction accuracy is maintained.
Solution Approach 2:
The system uses feedback by evaluating temperature changes and time intervals to determine whether pre-acquired offset images remain valid. When temperature drift or time degradation exceeds thresholds, the system detects that offset correction accuracy would deteriorate and switches to acquiring fresh offset images interleaved with radiation images. This feedback mechanism ensures that random noise reduction through averaging does not compromise correction accuracy.
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 proposed method effectively reduces image lag and random noise by dynamically adjusting the offset correction process, ensuring accurate image quality in radiographic imaging.
Implementation Method 1
The scintillator converts radiation into visible light
Implementation Method 2
The solid-state light detector includes an amorphous semiconductor sandwiched between a transparent conductive film and a conductive film
Data Source
AI summary
A radiographic imaging apparatus includes at least one processor and a memory in communication with the at least one processor, the memory storing instructions that, when executed by the at least one processor, cause the at least one processor to function as an image acquisition unit that alternately acquires a radiation image acquired in a state where radiation is emitted and an offset image acquired in a state where the radiation is not emitted and an offset correction unit that corrects, in a case where a change amount between an offset image acquired at a first time and an offset image acquired at a second time before the first time is smaller than a first threshold value, a radiation image acquired after the first time using a plurality of offset images including the offset image acquired at the first time and the offset image acquired at the second time.