Radiation Image Defect Pixel Correction Under Grid Stripe Interference
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Solution Overview
Problem
Existing radiation imaging systems face issues with defect pixels due to charge discharge during automatic radiation detection, leading to output value differences and stripe patterns, which are not accurately corrected by existing methods, especially when grids are used to remove scattered radiation.
Innovation Solution
An image processing apparatus that determines reference pixels adjacent to defect pixels and calculates correction coefficients to accurately correct defect pixels, accounting for grid stripe interference by using adjacent pixel values in specific directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If automatic radiation detection is implemented to eliminate interface requirements, then ease of operation is improved, but defect pixels occur due to charge discharge during irradiation
Solution Approach 1:
The patent applies preliminary action by performing reset operations on specific rows (odd or even rows alternately) before charge accumulation begins. This preliminary reset prevents charge discharge during irradiation for selected rows, thereby preventing defect pixels while maintaining automatic detection functionality. The system determines in advance which rows will be reset and processes them accordingly before the actual radiation detection occurs.
2Reliability
If reset operation is performed for alternate rows to prevent defect pixels, then reliability is improved, but stripe patterns appear due to output value differences between defect and normal rows
Solution Approach 1:
The patent extracts and corrects the stripe pattern artifact by identifying affected pixels in alternate rows and applying compensation processing. The image processing apparatus detects the stripe pattern caused by differential reset operations and removes this unwanted component through mathematical correction, thereby eliminating the visual artifact while preserving the underlying diagnostic information.
Solution Approach 2:
The patent changes the output parameter values of pixels in alternate rows by applying correction coefficients. These coefficients adjust the pixel values to compensate for the charge discharge effect, thereby equalizing the output values between rows that underwent reset operations and rows that did not, eliminating the stripe pattern appearance.
3Device complexity
If existing correction methods are used to address defect pixels, then processing simplicity is maintained, but correction accuracy deteriorates due to grid stripe interference
Solution Approach 1:
The patent segments the correction process into distinct stages: first identifying defect pixels in alternate rows, then determining correction coefficients specifically for these rows, and finally applying the corrections. This segmentation allows the system to handle grid stripe interference by processing affected rows separately from normal rows, thereby improving correction accuracy without requiring complete redesign of the correction methodology.
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
Highly accurate correction of defect pixels is achieved, even with grid interference, by using reference pixels and correction coefficients, ensuring consistent image quality.
Implementation Method 1
a radiation detector that includes a pixel region in which a plurality of pixels configured to detect radiation are provided in a matrix
Data Source
AI summary
An image processing apparatus corrects a target pixel in a radiation image using a radiation detector including a pixel region in which pixels detect radiation in a matrix. The apparatus includes a memory coupled to a processor. Instructions in the memory cause the processor to function as a pixel determination unit to determine a reference pixel from among four pixels vertically and horizontally adjacent to the correction target pixel in the radiation image. A pixel correcting unit corrects the correction target pixel in the radiation image using the reference pixel. The radiation detector obtains the radiation image by repeating reading out a charge accumulated in the pixels of one of an odd column and an even column of a first row and reading out a charge accumulated in the pixels of the other of the odd column and the even column of a second row adjacent to the first row.