Pixel Correction in Solid-State Image Sensors
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Solution Overview
Problem
Existing image processing technologies fail to effectively suppress image quality deterioration caused by defective pixels in solid-state image sensors using color filters with non-standard pixel arrangements, such as those with red and blue pixels at a pitch of 4 pixels or more, as traditional defect correction methods do not adequately address the unique spatial frequency characteristics of these sensors.
Innovation Solution
A signal processing device and method that corrects pixel signals from defective pixels in a solid-state image sensor by referencing pixel signals from luminance pixels with higher spatial frequencies, specifically using a correction processing unit to acquire and correct pixel signals from color pixels with lower spatial frequencies, thereby improving defect correction accuracy without erroneous chroma reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional defect correction methods are applied to sensors with non-standard pixel arrangements (red and blue pixels at pitch of 4 pixels or more), then the correction process can be implemented, but image quality deterioration caused by defective pixels cannot be effectively suppressed
Solution Approach 1:
The patent changes the fundamental parameter of spatial frequency relationship between color pixels and luminance pixels. Instead of assuming equal intervals (traditional Bayer array), the method accommodates non-standard arrangements where color pixels have lower spatial frequencies than luminance pixels, enabling effective defect correction for novel sensor architectures
Solution Approach 2:
The correction method dynamically adapts to different pixel arrangements by detecting the actual spatial frequency characteristics of the sensor and adjusting the correction algorithm accordingly, rather than using a fixed correction approach
2Use of energy by moving object
If color filters with white main component are used to attain high sensitivity, then luminance signal quality improves, but defect correction becomes more difficult due to lower spatial frequency of color pixels
Solution Approach 1:
The patent uses luminance pixels as an intermediary to correct defective color pixels. By leveraging the higher spatial frequency and better quality of luminance pixel signals, the method indirectly corrects color pixel defects through spatial interpolation and frequency domain processing
Solution Approach 2:
The patent transitions from correcting pixels in the spatial domain to correcting them in the frequency domain. By applying Fourier transforms and operating in the frequency domain, the method effectively handles the lower spatial frequency characteristics of color pixels with white main component filters
3Ease of operation
If conventional defect correction is used with equal interval color arrangement, then correction simplicity is maintained, but correction accuracy deteriorates for non-standard pixel arrangements
Solution Approach 1:
The patent creates a universal defect correction method that works across multiple pixel arrangement types (standard Bayer array, non-standard arrangements with 4x pitch, and sensors with white main component filters). The single algorithm adapts to different configurations through automatic detection and parameter adjustment
Data Source
AI summary
There is provided a signal processing device including a correction processing unit that acquires a pixel signal output from a sensor on which pixels are disposed in an array in which a spatial frequency of a color pixel which is a pixel acquiring a color component is lower than a spatial frequency of luminance pixels which are pixels acquiring luminance components, and then corrects the pixel signal output from a defective pixel out of the pixels that the sensor includes. During correction of a pixel signal of the color pixel, the correction processing unit performs correction referring to pixel signals of the luminance pixels having a spatial frequency higher than the spatial frequency of the color pixel.