Defective Pixel Correction Using Chromatic Aberration Compensation
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Solution Overview
Problem
As solid-state image sensors are miniaturized and increase in pixel number, defective pixels become more common, leading to challenges in accurately correcting image signals due to magnification chromatic aberration, which causes color shifts and affects image quality.
Innovation Solution
A defective pixel correction apparatus and method that includes a first corrector for linear interpolation and a second corrector for aberration correction, using a specific color signal to perform a second correction process, thereby addressing the issue of defective pixels and color shifts caused by magnification chromatic aberration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels in solid-state image sensors is increased, then the imaging resolution is improved, but the number of defective pixels increases
Solution Approach 1:
The patent performs preliminary identification of defective pixels before final image processing. By detecting and flagging defective pixels in advance through comparison of multiple color channel data, the system prepares correction strategies proactively, allowing subsequent correction processes to efficiently compensate for defective pixels without compromising overall image quality
Solution Approach 2:
The patent uses intermediate color channel data as a mediator for correction. When a pixel is defective in one color channel (e.g., R channel), the system retrieves corresponding pixel data from other color channels (G and B channels) as intermediary sources to reconstruct the missing information, thereby maintaining image completeness and quality
2Device complexity
If linear interpolation is used to correct defective pixels, then the correction process is simple, but color shifts occur due to magnification chromatic aberration
Solution Approach 1:
The patent segments the correction process into distinct stages: first identifying defective pixels, then retrieving data from specific color channels (G channel for R-defective pixels, B channel for G-defective pixels, R channel for B-defective pixels), and finally synthesizing corrected values. This segmentation allows each stage to be optimized independently, balancing simplicity with color accuracy
Solution Approach 2:
The patent changes the parameter selection strategy based on the type of defective pixel. Instead of using a fixed interpolation method, the system dynamically selects which color channel data to retrieve based on which channel contains the defective pixel, thereby adapting the correction parameters to the specific defect scenario and minimizing color shifts
3Measurement precision
If aberration correction is performed to address color shifts, then color accuracy is improved, but the correction process becomes more complex
Solution Approach 1:
The patent performs preliminary organization of color channel data before correction. By pre-arranging the retrieval logic for different color channel combinations based on defective pixel locations, the system prepares the necessary data structures and access patterns in advance, reducing the computational complexity during actual correction execution
Solution Approach 2:
The patent applies different correction strategies to different regions of the image based on local defect characteristics. Instead of applying a uniform complex aberration correction to the entire image, the system selectively applies correction only to pixels identified as defective, using locally adapted retrieval patterns from appropriate color channels, thereby reducing overall processing complexity while maintaining color 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 solution effectively corrects defective pixels by performing a first linear interpolation and a second aberration correction process, improving image quality by accurately addressing color shifts and enhancing the accuracy of defective pixel correction even in the presence of magnification chromatic aberration.
Implementation Method 1
The image sensors photoelectrically convert light beams incident on the respective pixels so as to output them as electric signals
Data Source
AI summary
A defective pixel correction apparatus and a defective pixel correction method of the present technique include a first defective pixel corrector for specifying a defective pixel included in an image signal of each of color signals sent from an imaging unit, and obtaining a linear interpolation value from pixels around the defective pixel to perform a first defective pixel correction process on the defective pixel by linear interpolation. Further, the defective pixel correction apparatus and the defective pixel correction method include a second defective pixel corrector for performing an aberration correction process based on an image signal of a specific color after the first defective pixel correction process, and performing a second defective pixel correction process different from the first defective pixel correction process on the pixel that has been subjected to the first defective pixel correction process.