False Color Detection via Dual Filter Demosaicing
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Solution Overview
Problem
Existing demosaicing methods often produce false colors, particularly in high-frequency image areas, due to the inability to accurately depict color values, leading to speckle color noise and color Moiré effects.
Innovation Solution
An edge preserving filter and a low-pass filter are applied to the Bayer image sensor output to generate two demosaiced images, with a hue difference calculated between them to detect false color regions, allowing for accurate detection and correction of false colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If demosaicing is performed using conventional interpolation methods, then complete color values for each pixel can be generated, but false colors and speckle noise appear in high-frequency areas
Solution Approach 1:
The patent segments the demosaicing process into multiple stages: first applying an edge-preserving filter to maintain color accuracy, then applying a low-pass filter to suppress false colors and speckle noise in high-frequency areas. This multi-stage segmentation allows each filter to specialize in different aspects of color reconstruction, resolving the contradiction between accuracy and noise suppression.
Solution Approach 2:
The patent applies different filtering operations to different frequency regions of the image. Edge-preserving filters are applied to maintain local color accuracy, while low-pass filters are applied to suppress false colors in high-frequency areas. This local differentiation of filter characteristics allows simultaneous optimization of both color accuracy and false color suppression in different image regions.
2Measurement precision
If edge-preserving filters are applied to maintain color accuracy, then color values are improved, but computational complexity increases
Solution Approach 1:
The patent applies the edge-preserving filter as a preliminary step before demosaicing to pre-process the Bayer pattern data. This preliminary action prepares the data in a way that simplifies subsequent demosaicing operations and reduces the need for complex post-processing, thereby managing computational complexity while maintaining color accuracy.
Solution Approach 2:
The patent maintains continuous filtering operations throughout the demosaicing pipeline, where edge-preserving filters operate continuously on the input data and low-pass filters continuously suppress false colors in the output. This continuous processing approach optimizes computational efficiency by avoiding repeated complex calculations while maintaining consistent color accuracy.
Data Source
AI summary
Devices, methods, and systems for detecting false color in an image. An edge preserving filter is applied to an image sensor output to generate a first demosaiced image. A low pass filter is applied to the image sensor output to generate a second demosaiced image. A hue difference between the first demosaiced image and the second demosaiced image is calculated. A false color region is detected responsive to the hue difference exceeding a threshold hue difference.