Pixel Interpolation for WRGB Color Filters Using Correlation Analysis
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Solution Overview
Problem
Existing pixel interpolation techniques are not directly applicable to single-chip image sensors with color filters other than the Bayer array, such as the WRGB array, leading to inadequate interpolation processing.
Innovation Solution
A pixel interpolation apparatus that evaluates color saturation and correlation degrees in multiple directions to determine an appropriate interpolation method, using change ratios calculated from neighboring pixel values in high-correlation directions for accurate interpolation, even when the same color component is not directly available in the correlation direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing pixel interpolation techniques are used, then processing is simple, but they are not directly applicable to single-chip image sensors with color filters other than the Bayer array
Solution Approach 1:
The patent changes the parameters of the interpolation processing by introducing color saturation evaluation and multi-directional correlation analysis. Instead of using fixed interpolation algorithms, the system dynamically adjusts the interpolation method based on color saturation values and correlation degrees in different directions, making it adaptable to various color filter patterns including WRGB arrays.
Solution Approach 2:
The patent implements dynamic interpolation by determining the interpolation method based on real-time analysis of color saturation and correlation degrees. The system dynamically selects between different interpolation approaches (such as using change ratios in high-correlation directions versus other methods) depending on the local image characteristics, making the processing adaptable to different color filter arrangements.
2Measurement precision
If pixel interpolation is performed using conventional methods, then processing speed is maintained, but interpolation accuracy deteriorates for non-Bayer color filter patterns
Solution Approach 1:
The patent segments the image processing into distinct stages: color saturation evaluation, correlation degree calculation in multiple directions, and conditional interpolation. By dividing the processing into these segments, the system can apply optimized algorithms for each stage, improving overall accuracy while maintaining efficient processing through systematic organization of operations.
Solution Approach 2:
The patent performs preliminary actions by calculating color saturation values and correlation degrees before executing the actual interpolation. This preliminary analysis allows the system to pre-determine the optimal interpolation method for each region, ensuring high accuracy from the start and avoiding the need for iterative adjustments that would consume additional time.
3Measurement precision
If color saturation evaluation and multi-directional correlation analysis are performed, then interpolation accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent applies local quality by performing color saturation evaluation and correlation analysis specifically in regions where interpolation is needed, rather than uniformly across the entire image. The system analyzes local image characteristics and applies appropriate interpolation methods only where necessary, improving accuracy while reducing overall processing complexity through localized operations.
Data Source
AI summary
An imaging apparatus includes an imaging unit, a signal processing unit, and a pixel interpolation processing unit. The apparatus calculates a correlation degree for pairs in two orthogonal directions for an image signal obtained by the imaging unit including a single-chip image sensor having a four-color filter, such as a WRGB color filter, using pixel data in an area around a target pixel, using the correlation degree as a determination criterion in the interpolation. When a color component pixel with an identical color of a color component pixel subjected to pixel interpolation is not located in the direction having the high correlation, the pixel interpolation apparatus changes ratio in a direction orthogonal to the direction having the high correlation by using a pixel value resulting from color space conversion in the direction orthogonal to the direction having the high correlation, and performs pixel interpolation based on the change ratio.