Wide-Angle Lens Distortion Correction Using Radii-Ratio Lookup Tables
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Solution Overview
Problem
Conventional wide-angle lens cameras struggle with accurate distortion correction, resulting in low-quality images due to curvature errors and high power consumption, especially when handling high SMIA TV distortion levels, which affects real-time video processing and image quality requirements.
Innovation Solution
The implementation of a distortion correction method that uses a radii-ratio look-up table and homography transformation to accurately determine pixel interpolation points, reducing power consumption and improving image quality by following the curvature of physical distortion and accounting for both radii-ratio-based lens distortion correction and homography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional distortion correction methods are used, then processing speed can be maintained, but image quality deteriorates due to curvature errors and interpolation inaccuracies
Solution Approach 1:
The patent pre-calculates and stores distortion correction parameters (radii ratios, interpolation coefficients) in lookup tables before actual image processing. This preliminary computation of correction maps allows the real-time processing stage to simply retrieve and apply pre-computed values, achieving both high accuracy (reducing interpolation errors to less than 0.1 pixels) and high speed (enabling real-time video processing at 30-60 fps).
Solution Approach 2:
The patent divides the distorted image into multiple blocks or regions, each processed with locally optimized interpolation parameters. By segmenting the image and applying region-specific correction coefficients from the lookup tables, the system achieves higher overall accuracy while maintaining processing efficiency through parallel block processing.
2Productivity
If hardware-accelerated distortion correction is implemented, then processing performance improves, but power consumption increases
Solution Approach 1:
The patent performs computationally intensive operations (distortion model fitting, radii ratio calculations, interpolation coefficient generation) during an offline calibration phase and stores results in compact lookup tables. During real-time operation, the hardware accelerator only needs to perform simple table lookups and basic arithmetic operations, dramatically reducing power consumption while maintaining high correction performance.
Solution Approach 2:
The patent uses simplified interpolation models and approximate correction algorithms that require less computational resources. By accepting small, controlled deviations in favor of lower computational complexity, the system reduces hardware requirements and power consumption for devices with limited processing capacity.
3Measurement precision
If accurate distortion correction is applied, then image quality improves, but computational complexity and processing time increase
Solution Approach 1:
The patent transforms the complex non-linear distortion correction problem into a series of simpler parameter-based transformations. By representing distortion as radial scaling factors and using lookup tables with pre-computed radii ratios, the system achieves accurate correction through simple parameter application rather than complex iterative optimization during real-time processing.
Solution Approach 2:
The patent introduces intermediate lookup tables that store pre-computed correction parameters as a mediator between the complex distortion model and the simple image processing operations. These tables act as an intermediary layer that translates complex optical distortion characteristics into straightforward interpolation coefficients, reducing computational complexity while maintaining accuracy.
Data Source
AI summary
Techniques related to image distortion correction for images captured by using a wide-angle lens include homography and a lens distortion correction using a radial-ratio-based look up table.