Radiation Imaging Pixel Array Noise Correction via Preliminary Dark Data
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Solution Overview
Problem
Radiation imaging apparatuses using the photon counting scheme face challenges in maintaining image quality due to temperature-dependent noise, which requires lengthy data collection for noise correction, thereby increasing photographing time.
Innovation Solution
The apparatus employs a pixel array with a detection element that holds voltage changes based on detected radiation photons, allowing for non-destructive reading of pixel signals and generating image data by calculating differences between frames, thereby reducing noise components without the need for extensive correction data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction data is obtained by reading pixel data without radiation irradiation to remove noise components, then image quality is maintained, but photographing time increases significantly
Solution Approach 1:
The invention performs preliminary noise characterization by reading pixel data without radiation irradiation to obtain correction data (dark image data) before actual imaging. This preliminary action stores the noise components in memory, allowing subsequent rapid subtraction from pixel data during photon counting without requiring repeated non-irradiation readings, thus maintaining image quality while reducing photographing time.
2Measurement precision
If multiple frames of pixel data are read out repeatedly to obtain correction data, then noise components can be removed, but the imaging process becomes complex and time-consuming
Solution Approach 1:
The invention extracts noise components from pixel data by performing a single non-irradiation readout to obtain dark image data, then separates this correction data from subsequent imaging frames. By extracting and storing the noise characteristics once, the system eliminates the need for repeated extraction operations, simplifying the imaging process while maintaining noise removal accuracy through straightforward data subtraction.
3Measurement precision
If the pixel array is repeatedly irradiated and non-irradiated to collect correction data, then noise correction is achieved, but productivity decreases
Solution Approach 1:
The system performs the noise correction preparation in advance by conducting a single non-irradiation readout to capture dark image data before the actual imaging sequence begins. This preliminary action stores correction data in memory, enabling subsequent frames to be processed at full speed without interruption for noise correction, thereby maintaining high imaging speed while achieving accurate noise correction.
Solution Approach 2:
The invention maintains continuous imaging operation by performing noise correction through data processing rather than interrupting the imaging sequence with repeated non-irradiation readings. The correction data obtained preliminarily is continuously applied to subsequent frames through subtraction, allowing the useful action of radiation detection to proceed without interruption, thus maximizing productivity while maintaining 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
This approach significantly shortens the photographing time while maintaining image quality, achieving a frame rate of about 90 FPS compared to 20 FPS in traditional methods, and simplifies control of imaging units by eliminating the need for repeated irradiation and non-irradiation cycles.
Implementation Method 1
a detection element configured to detect a radiation photon
Data Source
AI summary
A radiation imaging apparatus includes a pixel array in which a plurality of pixels are arrayed and a processing unit configured to process pixel signals non-destructively read out from the respective pixels. The processing unit performs a first process of obtaining image data of a plurality of frames by repeatedly reading out image data while the pixel array is irradiated with radiation, with a group of pixel signals from the plurality of pixels corresponding to image data of one frame, and a second process of generating data for a radiation image based on data differences between the image data of the plurality of frames.