Image Distortion Correction Using 2D Lookup Table for Free-Shape Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image processing methods for correcting distortion in wide-angle and fisheye lens images are inefficient, leading to increased processing time, circuit size, and cost, particularly when handling free shapes and requiring real-time viewpoint conversions.
Innovation Solution
An image processing method using a two-dimensional Lookup Table (LUT) to calculate pixel coordinates on a virtual projection plane with a free curved surface, allowing for distortion correction based on a fixed datum plane and reducing processing time while maintaining high visual recognizability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cylindrical distortion correction or spherical distortion correction is applied, then visual recognizability is improved, but processing time increases and circuit scale augments
Solution Approach 1:
The patent changes the mathematical parameters of distortion correction by introducing a free shape correction method that uses a lookup table (LUT) approach. Instead of using traditional cylindrical or spherical correction parameters, the system pre-calculates correction values for various distortion types and stores them in a lookup table, allowing for faster processing while maintaining high correction accuracy for complex free shapes.
Solution Approach 2:
The patent creates a virtual projection plane that copies the characteristics of the actual projection surface. By constructing a virtual plane with the same shape and size as the actual projection surface, the system can apply distortion correction without requiring complex real-time calculations, thus reducing processing time while maintaining correction accuracy.
2Manufacturing precision
If free shape distortion correction is applied to improve visual recognizability, then correction accuracy is improved, but processing time increases and circuit scale augments
Solution Approach 1:
The patent performs preliminary calculations by pre-computing distortion correction values for various points on the projection surface and storing them in a lookup table. This preliminary action allows the actual distortion correction process to simply retrieve pre-calculated values rather than performing complex real-time calculations, thereby reducing circuit complexity while maintaining high accuracy for free shape corrections.
Solution Approach 2:
The patent replaces complex mechanical calculation systems with a data-driven approach using lookup tables. Instead of using complex mathematical models and real-time calculations, the system uses pre-stored correction data that can be quickly retrieved and applied, substituting computational complexity with data storage and retrieval operations.
3Manufacturing precision
If distortion correction is applied using correction parameters, then distortion is corrected, but resolution decreases when cutting out images at end portions
Solution Approach 1:
The patent applies local quality correction by treating different regions of the image differently. Instead of applying a uniform correction parameter across the entire image, the system calculates and applies local correction values for each region, particularly paying attention to end portions where distortion is most severe. This allows for high-resolution output while maintaining distortion correction accuracy.
4Adaptability or versatility
If real-time image processing for zoom, pan and tilt conversions is applied, then operational flexibility is improved, but processing time increases, circuit scale augments and cost increases
Solution Approach 1:
The patent creates a universal distortion correction system that can handle multiple operations (zoom, pan, tilt) through a single lookup table-based approach. By constructing a virtual projection plane that can be configured for different viewpoints and applying the same LUT retrieval mechanism, the system achieves multi-functionality without requiring separate complex processing pipelines for each operation, thus reducing processing time and circuit complexity.
Data Source
AI summary
An image processing method, an image processing apparatus and an image capturing apparatus are provided, which are capable of obtaining an output image exhibiting high visual recognizability while reducing the processing time with a circuit on a comparatively small scale. Datum plane system coordinates xdydzd with a datum plane DP serving as a basis and having a fixed positional relationship with a virtual projection plane VP are set, and there is provided a two-dimensional LUT stored with zd coordinates in a direction perpendicular to the datum plane with respect to xd- and yd-coordinates on the datum plane DP and based on a shape of the virtual projection plane VP, and image data is calculated, by calculating the coordinates of the pixels on the virtual projection plane VP in the world coordinate system on the basis of the two-dimensional LUT and converting the calculated coordinates of the pixels on the virtual projection plane in the world coordinate system into a camera coordinate system by using a distortion correction coefficient of an optical system.