Polarization Imaging Pixel Defect Detection Using Cross-Directional Estimation
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Solution Overview
Problem
Existing image processing methods for defect detection in polarization imaging devices do not account for the unique polarization characteristics of pixels, leading to ineffective defect detection and correction in polarization imaging systems.
Innovation Solution
An image processing apparatus and method that utilize pixel values from peripheral pixels in different polarization directions to estimate the value of a target polarized pixel, determining defects based on predetermined allowable ranges and ratios, and include a white balance adjusting section to equalize pixel values for accurate defect detection and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional defect detection methods using peripheral pixels with identical polarization direction are used, then the detection process is simple, but the detection accuracy is insufficient for polarization imaging devices
Solution Approach 1:
The patent transitions from using only peripheral pixels in the same polarization direction to utilizing pixels across multiple polarization directions (0°, 45°, 90°, 135°). This dimensional expansion in polarization space enables more comprehensive defect detection by comparing target pixels with peripheral pixels having different polarization characteristics, thereby improving detection accuracy while accounting for the unique structure of polarization imaging devices
Solution Approach 2:
The patent changes the detection parameters by incorporating polarization direction as an additional dimension. Instead of solely comparing pixel intensity values, the method now considers polarization characteristics by selecting peripheral pixels from multiple polarization directions and applying appropriate weighting factors, thus transforming the detection approach to suit polarization imaging devices
2Measurement precision
If pixel values from multiple polarization directions are used for estimation, then the defect detection accuracy improves, but the calculation complexity increases
Solution Approach 1:
The patent applies local quality by assigning different weighting factors to peripheral pixels based on their polarization directions relative to the target pixel. Specifically, pixels with polarization directions that are 45° apart from the target pixel are given higher weights (α and β), while pixels with the same polarization direction are given lower weights (γ and δ). This localized weighting strategy improves estimation accuracy by emphasizing more relevant polarization information while managing computational complexity through selective weighting
3Reliability
If defect detection considers polarization characteristics of peripheral pixels, then the reliability of defect identification improves, but the processing time increases
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing the weighting factors (α, β, γ, δ) that correspond to different polarization direction relationships. These weighting factors are determined in advance based on the polarization characteristics of the imaging device, allowing the defect detection process to quickly apply predefined weights without performing complex real-time calculations, thus improving reliability while minimizing processing time
Data Source
AI summary
A polarization imaging section 20 includes polarized pixels in each of a plurality of polarization directions. The polarization imaging section 20 includes a polarizer. The polarization imaging section 20 outputs image signals of a polarized image to a defect detecting section 35 of an image processing section 30. In a case where a difference between a pixel value of a target polarized pixel generated by the polarization imaging section and a pixel value of the target polarized pixel estimated from polarization characteristics corresponding to pixel values of peripheral pixels in a polarization direction different from a polarization direction of the target polarized pixel is greater than a predetermined allowable range, the defect detecting section 35 determines that the target polarized pixel is a defective pixel. Therefore, it is possible to detect a defect of a pixel in the polarization imaging section that generates the polarized image.