Lens Shading Compensation in HDR Image Processing
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Solution Overview
Problem
Lens shading effect causes distortion in images due to varying light intensity across the camera lens, particularly affecting color channels, which existing image processing technologies have not adequately addressed.
Innovation Solution
A method and system for lens shading compensation that involves receiving source images of different exposure settings, analyzing their statistics, composing High Dynamic Range (HDR) images, and performing lens shading compensation in the raw image domain, with multiple stages of compensation to adjust color values based on pixel position and luminance distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lens shading compensation is performed on source images before HDR composition, then color values at edges and corners are restored, but additional processing steps are required increasing system complexity
Solution Approach 1:
The patent performs lens shading compensation on source images before HDR composition to pre-correct color values at edges and corners. This preliminary action ensures that the compensation is applied to the raw data before any processing, maintaining color accuracy throughout the HDR pipeline without requiring complex post-processing adjustments
2Manufacturing precision
If multiple stages of lens shading compensation are applied, then color distribution accuracy is improved, but processing time increases
Solution Approach 1:
The patent applies lens shading compensation in multiple stages: first on the source images before HDR composition, and then on the final HDR image. This preliminary action on source images prevents color distortion from propagating through the HDR pipeline, while the second stage on the HDR image provides final refinement, achieving high color distribution accuracy through systematic multi-stage processing
3Measurement precision
If lens shading compensation is performed in raw image domain, then color accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent performs lens shading compensation in the raw image domain before any other processing operations. This preliminary action on raw data ensures that color values are corrected at the most fundamental level, preventing distortion from affecting subsequent HDR composition and other processing steps, thereby maintaining high color measurement accuracy throughout the pipeline
Data Source
AI summary
A method for performing lens shading compensation is provided. The method includes: receiving at least two series of source images of different exposure settings; performing first lens shading compensation on the at least two series of source images respectively; analyzing luminance distribution of the at least two series of compensated source images; composing a series of HDR images from the at least two series of compensated source images according to the luminance distribution; performing second lens shading compensation on the series of HDR image; and performing tone mapping on the series of compensated HDR images. A system for performing lens shading compensation is also provided.