Demosaicing Apparatus Edge Preservation Spurious Resolution
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Solution Overview
Problem
Conventional demosaicing techniques, such as bilinear and bicubic interpolation, can generate spurious resolutions or false colors in images with high frequency components, especially when the edge direction of an object is not accurately detected, leading to interpolation errors near the resolution limit of the image sensor.
Innovation Solution
An image processing apparatus and method that performs demosaicing by interpolating pixel data in multiple directions, evaluating the interpolation results, detecting saturation, and judging the occurrence of spurious resolutions, allowing for accurate selection of interpolation direction and data generation to preserve edge components and avoid color artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bilinear or bicubic interpolation is used for demosaicing, then low frequency components are reproduced well, but spurious resolutions or false colors occur in high frequency components
Solution Approach 1:
The patent changes the parameter of interpolation direction by detecting edge directions in multiple directions (e.g., horizontal, vertical, diagonal) and selecting the appropriate interpolation method based on the detected edge orientation. This allows the system to adapt to different frequency components and avoid spurious resolutions while maintaining interpolation accuracy.
2Ease of operation
If demosaicing is performed using pixels in a direction different from the edge direction, then interpolation is simplified, but spurious resolutions or false colors occur
Solution Approach 1:
The patent makes the interpolation process dynamic by detecting edge directions and adaptively selecting the interpolation direction based on the detected edge orientation. This dynamic adaptation ensures that interpolation is always performed along or across the edge direction appropriately, preventing false colors while maintaining process efficiency.
3Extent of automation
If the evaluation value of uniformity is used to determine edge direction, then interpolation direction selection is automated, but incorrect evaluation values occur near the resolution limit
Solution Approach 1:
The patent introduces feedback mechanisms by evaluating interpolation results and detecting saturation to verify whether the selected interpolation direction is appropriate. This feedback loop allows the system to correct incorrect evaluations near the resolution limit and prevent spurious resolutions from occurring.
4Measurement precision
If multiple interpolation directions are evaluated to select the best direction, then interpolation accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent applies local quality by performing detailed multi-directional evaluation only in regions where edges are detected, while using simpler interpolation methods in flat regions. This localized approach maintains high interpolation accuracy at edges while reducing overall processing complexity.
Data Source
AI summary
A demosaicing unit interpolates mosaic image data of each pixel of interest so as to reproduce colors missing at each pixel by interpolation using neighboring pixels. In the demosaicing unit, an interpolation unit performs an interpolation process in a plurality of prescribed directions using neighboring pixels in the prescribed directions. An evaluation unit evaluates image data in each prescribed directions interpolated by the interpolation unit. A spurious resolution area judgment unit judges whether a pixel is in a spurious resolution area, on a pixel-by-pixel basis, based on a saturation detected from image data subjected to an interpolation process performed so as to preserve an edge component. An image generation unit selects image data to be interpolated for each pixel based on a result of the evaluation by the evaluation unit and a result of the judgment by the spurious resolution area judgment unit, and generates interpolated image data.