One-Dimensional Lens Shading Correction Curves
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Solution Overview
Problem
Image capturing systems suffer from lens shading artifacts due to non-uniform light distribution, causing light intensity to fall off towards the edges of captured images, which existing methods struggle to correct efficiently.
Innovation Solution
The method employs two one-dimensional correction curves, Lh(x) and Lv(y), instead of a single two-dimensional function to correct lens shading artifacts, simplifying computations and reducing storage requirements, by applying horizontal and vertical corrections independently and using morphing techniques to approximate correction functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a two-dimensional function L(x,y) is used to correct lens shading artifacts, then correction accuracy is improved, but computational complexity and storage requirements increase
Solution Approach 1:
The patent divides the two-dimensional correction function L(x,y) into multiple one-dimensional correction curves along different directions (horizontal, vertical, diagonal). Instead of computing a single 2D function, the system segments the correction into multiple 1D curves that can be computed and stored separately, reducing overall computational and storage complexity while maintaining correction accuracy.
Solution Approach 2:
The patent transforms the problem from a two-dimensional function L(x,y) into multiple one-dimensional functions by introducing directional dimensions. The correction is performed by combining 1D curves from different directions (e.g., horizontal curve Lh(x), vertical curve Lv(y), diagonal curves), effectively using dimensionality change to simplify the mathematical representation and computation.
2Measurement precision
If a two-dimensional function L(x,y) is used to correct lens shading artifacts, then correction accuracy is improved, but storage requirements increase
Solution Approach 1:
The patent segments the 2D correction function into multiple 1D correction curves stored in separate lookup tables. This segmentation reduces storage requirements because storing multiple 1D arrays requires less memory than storing a single 2D array of the same resolution, while still providing accurate correction when the curves are combined during image processing.
3Reliability
If traditional lens shading correction methods are used, then correction effectiveness is maintained, but processing time increases
Solution Approach 1:
The patent performs preliminary action by pre-computing and storing the one-dimensional correction curves in lookup tables before actual image processing. This allows the correction to be applied rapidly during image processing by simply looking up pre-computed values and combining them, rather than computing the correction function in real-time, thus reducing processing time while maintaining correction effectiveness.
Data Source
AI summary
In one embodiment, a method for correcting image data for a captured image for lens shading artifacts is provided. The method comprises determining a plurality of one dimensional correction curves that can be applied to the image data to correct for lens shading artifacts therein; and correcting the image data for lens shading artifacts based on the one dimensional curves.