Radiation Imaging Sensor Gain Correction via Dual Light Reset
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Solution Overview
Problem
Existing digital X-ray imaging apparatuses face challenges in performing adequate gain correction due to non-uniform light reset, leading to artifacts in images caused by distribution of dark signals and image lag across the sensor unit.
Innovation Solution
A radiation imaging apparatus with a two-dimensional sensor unit and a light source that corrects image signals based on correction signals derived from both light-irradiated and non-light-irradiated pixels, allowing for gain correction using data from radiation images obtained with and without light reset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light reset is performed to reduce dark signals and image lag, then image quality is improved, but non-uniform light distribution causes gain correction to become inadequate
Solution Approach 1:
The sensor unit is divided into light-irradiated pixels and non-light-irradiated pixels, with separate correction signals generated for each segment. This segmentation allows the system to account for different response characteristics in different regions of the sensor, resolving the non-uniformity issue while maintaining overall image quality improvement from light reset.
Solution Approach 2:
Different correction approaches are applied to different regions of the sensor unit. Light-irradiated pixels receive correction based on their specific response to light reset, while non-light-irradiated pixels receive correction based on their baseline response. This local quality approach ensures accurate gain correction across the entire sensor despite non-uniform light distribution.
2Object-affected harmful factors
If light reset is applied to inhibit dark signals, then noise is reduced, but artifacts are introduced due to non-uniform light distribution across the sensor
Solution Approach 1:
The non-uniform light distribution, which initially causes artifacts, is converted into a useful correction signal. By measuring the response of light-irradiated pixels and using this information to generate correction signals, the system transforms the harmful non-uniformity into a beneficial correction mechanism that actually improves image quality.
Solution Approach 2:
The system uses the response of light-irradiated pixels as feedback to generate correction signals that are applied to non-light-irradiated pixels. This feedback mechanism allows the system to continuously adjust and compensate for non-uniform light distribution, converting potential artifacts into corrected image data.
3Measurement precision
If gain correction is performed using conventional methods, then pixel gain differences are addressed, but non-uniform light reset creates residual artifacts
Solution Approach 1:
Correction signals are generated in advance by irradiating light on specific pixels before the actual imaging process. This preliminary action creates a correction map that can be applied during image acquisition, allowing the system to pre-compensate for non-uniform light distribution and gain differences, thereby improving both gain correction accuracy and image uniformity.
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 gain correction for radiographing conditions, reducing artifacts and improving image quality by accounting for variations in pixel sensitivity and light distribution across the sensor unit.
Implementation Method 1
a sensor unit including a plurality of pixels each having a photoelectric conversion element
Implementation Method 2
an indirect radiation imaging apparatus having a wavelength conversion element such as a phosphor that converts the X-rays into light of a waveband perceptible by the photoelectric conversion elements
Data Source
AI summary
The invention intends to be able to perform a gain correction fully adequately. Hence, at the time of radiographing an object, a gain correction of the object image is performed based on a gain correction image (XRc1) derived by performing a light reset. On the other hand, at the time of radiographing an object, when a light reset is not performed, a gain correction of the object image is performed based on a gain correction image (XRc2) derived without performing the light reset.