Color Fringing Estimation and Compensation in Image Processing
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Solution Overview
Problem
Conventional methods fail to effectively suppress color fringing around saturated pixels in color images due to chromatic aberration, particularly in digital cameras, where accurate point spread function is difficult to obtain and existing techniques either incompletely correct or overly alter the image, leading to unnatural results.
Innovation Solution
An image processing apparatus and method that estimates color fringing information and generates modified image data to compensate for chromatic aberration by employing spatial calculations, convolution processing, and excessive removal suppression techniques, allowing for effective reduction of color fringing while preserving original image colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If deconvolution and approximate edge enhancement processing are used to correct longitudinal chromatic aberration, then color fringing can be reduced in normal brightness ranges, but the method cannot obtain proper results unless an accurate point spread function is known and cannot reduce color fringing around saturated pixels
Solution Approach 1:
The patent changes the processing approach from deconvolution (which requires accurate PSF) to a chroma reduction method that operates directly on the captured image data. By detecting saturated pixels and applying chroma reduction in their vicinity, the method avoids the need for accurate PSF measurement while effectively addressing color fringing in both normal and saturated regions.
Solution Approach 2:
The patent extracts and processes only the chroma (color information) component in regions affected by color fringing, rather than applying complex deconvolution to the entire image. This extraction approach allows selective correction of color fringing without requiring full PSF accuracy.
2Object-affected harmful factors
If chroma is decreased in a region where color fringing occurs to make longitudinal chromatic aberration less conspicuous, then color fringing becomes less noticeable, but the original object color is also influenced and becomes grayish
Solution Approach 1:
The patent applies chroma reduction selectively only in regions where color fringing is detected (near saturated pixels), while leaving other regions unchanged. This localized approach ensures that original object colors are preserved in non-fringing areas while reducing color fringing where it occurs.
Solution Approach 2:
The patent uses the captured image data itself to detect saturated pixels and determine where color fringing occurs, then applies chroma reduction based on this feedback. This feedback mechanism ensures that chroma is reduced only where necessary to address color fringing, preserving original colors elsewhere.
3Volume of moving object
If the optical system is downsized and image sensor resolution is increased to meet compact digital camera demands, then camera compactness and resolution are improved, but chromatic aberration suppression becomes more difficult
Solution Approach 1:
The patent replaces optical correction mechanisms (mechanical/optical system design) with image processing methods. By using chroma reduction processing on captured image data, the system can correct chromatic aberration without requiring complex optical designs, enabling compact camera systems to achieve effective chromatic aberration suppression.
Data Source
AI summary
This invention more effectively suppresses color fringing in a color image by image processing. An image processing method includes estimating the degree of color fringing in a color image based on the color image that is generated by photo-electrically converting an object image and formed from a plurality of color planes. The method also includes removing from the color image the estimated degree of color fringing.