Piecewise-Quadratic Pixel Correction for Lens Shading
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Solution Overview
Problem
Existing image processing methods for correcting non-uniform pixel responses in image arrays, such as those caused by lens shading, require significant memory and computational resources, and are limited in their ability to accurately account for vertical variations across the pixel array.
Innovation Solution
The method generates piecewise-quadratic correction functions for each row of the pixel array in real time, eliminating the need for stored parameters and cross-term multiplication, allowing for more accurate and efficient correction of pixel values by using separate Fx(x) functions for each row and Fy(y) functions to update parameters dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piecewise-quadratic correction functions are generated for each row in real time, then correction accuracy for vertical variations is improved, but computational complexity increases
Solution Approach 1:
The pixel array is divided into multiple rows, and separate piecewise-quadratic correction functions Fx(x) are generated for each row. This segmentation allows the correction to account for vertical variations by treating each row independently, improving accuracy while managing computational complexity through structured division of the correction task.
Solution Approach 2:
The correction functions are generated dynamically in real-time during image processing rather than being pre-computed and stored. The Fy(y) functions update parameters dynamically to generate row-specific Fx(x) functions, enabling adaptive correction that responds to the specific needs of each row while avoiding the need for storing large amounts of correction data.
2Measurement precision
If separate Fx(x) functions are generated for each row, then correction precision for lens shading is improved, but memory requirements are reduced
Solution Approach 1:
Instead of storing pre-computed correction values for all pixels, the system dynamically generates Fx(x) functions for each row during image processing. The Fy(y) functions serve as parameter templates that are evaluated in real-time to produce row-specific corrections, reducing memory requirements while maintaining high correction precision.
Solution Approach 2:
The system uses parameterized piecewise-quadratic functions where the coefficients are determined by Fy(y) functions. By changing parameters dynamically based on row position rather than storing complete correction lookup tables, the system achieves precise correction with reduced memory footprint.
3Productivity
If real-time generation of correction functions is implemented, then processing efficiency is improved, but hardware complexity is reduced
Solution Approach 1:
The system replaces complex hardware correction mechanisms with software-based mathematical functions. By using piecewise-quadratic functions that can be evaluated through standard arithmetic operations, the patent achieves real-time correction without requiring specialized hardware circuits, improving processing efficiency while keeping hardware complexity manageable.
Data Source
AI summary
Methods, apparatuses and systems providing pixel correction values for a captured image, where the correction values are determined based on a piecewise-quadratic correction function in a first direction. The parameters for the piecewise-quadratic correction function in the first direction are calculated based on a plurality of piecewise-quadratic correction functions in a second direction. The correction values may be positional gain adjustment values.