Pixel Interpolation for Arbitrary Color Filter Arrays
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Solution Overview
Problem
Existing image capture technologies face challenges in performing accurate pixel interpolation for images captured by image sensors with three-color filters arranged in arbitrary patterns, particularly in distinguishing and processing gray and color areas effectively to prevent false colors.
Innovation Solution
A pixel interpolation apparatus and method that includes signal correction, saturation evaluation, gray and color correlation calculations, and interpolation units to determine the appropriate interpolation method based on saturation and correlation values, followed by color space conversion to handle images from sensors with three-color filters, ensuring accurate interpolation regardless of filter arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single image sensor with three-color filters is used to capture images, then the device complexity is reduced compared to using multiple sensors, but the manufacturing precision of pixel interpolation deteriorates due to the need to reconstruct missing color information
Solution Approach 1:
The patent segments the image processing into distinct stages: signal correction based on filter characteristics, saturation evaluation to identify color intensity, correlation calculation to determine spatial relationships, and selective interpolation only where needed. This segmentation allows precise control over the interpolation process, improving accuracy while maintaining simple sensor hardware
Solution Approach 2:
The patent performs preliminary signal correction for each color channel based on the specific characteristics of each filter before interpolation. By pre-correcting signal levels and evaluating saturation in advance, the system prepares the data optimally for interpolation, ensuring high precision without requiring complex sensor designs
2Manufacturing precision
If pixel interpolation is performed to obtain complete color information for all pixels, then the image quality improves, but false colors may occur in gray areas and border regions
Solution Approach 1:
The patent applies different processing strategies to different regions of the image based on local characteristics. Gray areas with low saturation use grayscale interpolation methods, while color-rich areas use full color interpolation. Border regions are detected and handled with special correlation calculations. This local adaptation prevents false colors while maintaining overall image quality
Solution Approach 2:
The patent incorporates feedback mechanisms through saturation evaluation and correlation calculation that continuously assess the suitability of interpolation in different regions. The system uses calculated correlation values and saturation levels to feedback-controlled decisions about whether and how to interpolate, preventing false color generation while preserving image quality
3Object-affected harmful factors
If different interpolation methods are used for gray areas and color areas, then false color suppression improves, but the device complexity increases due to multiple processing paths
Solution Approach 1:
The patent changes processing parameters dynamically based on image content characteristics. Saturation levels serve as a key parameter that determines which interpolation method to apply. Correlation values in different directions (horizontal, vertical, diagonal) are calculated and used to adjust processing behavior. These parameter changes enable false color suppression without requiring physically complex hardware, as the complexity is managed through adaptive software processing
Data Source
AI summary
An image capture apparatus 1000 includes an image capture unit C1, a signal processor unit C2, and a pixel interpolation unit 100. In the image capture apparatus 1000, with respect to an image signal captured by the image capture unit C1 which includes a single image sensor having three-color filters in arbitrary colors, a plurality of pairs of correlation degrees of two directions which are perpendicular to each other are obtained using image data of pixels provided around an observed pixel, and a pixel interpolation process is carried out using the correlation degrees as a reference for determination. Then, in the image capture apparatus 1000, even if a color component pixel in the same color as a color component pixel on which the pixel interpolation process is to be carried out is not provided in a direction where there is strong correlation, a rate of change in a direction perpendicular to the direction where there is strong correlation is obtained using a pixel value which is obtained though color space conversion in the direction perpendicular to the direction where there is strong correlation. Thus, a pixel interpolation process is carried out based on the obtained rate of change.