Adaptive Pixel Sensitivity Analyzer and Corrector
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Solution Overview
Problem
Sensitivity differences between green pixels (Gr and Gb) in image sensors, caused by non-uniformity in pixel arrays and color filter films, lead to image quality degradation due to uneven sensitivity across the sensor.
Innovation Solution
An adaptive analyzer and corrector system that divides same-color pixels into groups based on their relative positions, calculates and applies correction ratios per macro block to equalize pixel values, using an accumulator, calculator, and correction ratio controller to dynamically adjust sensitivity differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensitivity correction is applied to equalize pixel values, then image quality improves, but overcorrection may occur causing new artifacts
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting correction ratios based on local image characteristics. The system modifies the correction strength parameter according to the variance of pixel values in different regions, applying stronger correction where needed and weaker correction where pixel values are already uniform, thus preventing overcorrection artifacts
Solution Approach 2:
The patent implements dynamics by making the correction process adaptive rather than static. The correction ratio is dynamically calculated for different macro blocks based on local pixel value distributions, allowing the system to respond to varying sensitivity differences across different regions of the image sensor
2Device complexity
If global correction is applied to all pixels, then processing simplicity is maintained, but local sensitivity differences cannot be addressed
Solution Approach 1:
The patent applies segmentation by dividing the image into multiple macro blocks and further into different pixel groups (Gr pixels and Gb pixels). This allows independent correction analysis for each segment, capturing local sensitivity differences while maintaining manageable processing complexity through systematic organization
Solution Approach 2:
The patent implements local quality by applying different correction ratios to different regions of the image. Each macro block receives customized correction based on its local pixel value characteristics, ensuring that local sensitivity differences are addressed appropriately rather than applying a uniform correction across the entire image
3Measurement precision
If correction values are applied without clipping, then correction effectiveness is maximized, but pixel value saturation occurs
Solution Approach 1:
The patent applies preliminary anti-action by preemptively clipping correction values to prevent pixel saturation before it occurs. The clipping operation limits correction values to a safe range, counteracting the potential harmful effect of overcorrection that would push pixel values beyond the valid range
Data Source
AI summary
According to an embodiment, an adaptive analyzer of sensitivity difference of same color pixels analyzes a sensitivity difference of same color pixels of an image sensor. The same color pixels are divided into first and second groups. The adaptive analyzer includes an accumulator, a calculator, a correction ratio controller and a memory. The accumulator is configured to cumulatively add pixel values of pixels in the first group and pixel values of pixels in the second group per macro block, respectively, on an image captured in the image sensor. The calculator is configured to calculate a ratio between a cumulatively added value of the pixels in the first group and a cumulatively added value of the pixels in the second group in the macro block. The correction ratio controller is configured to set a correction ratio for the sensitivity difference based on the ratio per macro block.