Lens Distortion Correction via Spatial Geometric Calibration
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Solution Overview
Problem
Image distortion caused by misalignment of the optic lens center and image sensor unit in image capture devices leads to decreased accuracy in lens distortion correction, as the deformation does not exhibit point symmetry with respect to the image center, affecting the quality of formed images.
Innovation Solution
A spatial geometric calibration method is employed, using a geometric calibration model with calibration markers to determine the correct image center parameter through an LMS algorithm, transforming the image by selecting candidate center points to minimize error values and achieve point symmetry in image coordinate transformation, thereby correcting barrel or pincushion distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optic lens center is not located on the normal line from the center of the image sensor unit due to assembly tolerance or fault, then the distortion cannot have point symmetry with respect to the image center, but this misalignment decreases the accuracy of correction
Solution Approach 1:
The patent performs preliminary geometric calibration by capturing images of calibration markers at multiple positions before actual distortion correction. This preliminary action establishes the relationship between the lens center and image sensor center, allowing the system to compensate for assembly misalignment and achieve accurate distortion correction despite manufacturing tolerances.
Solution Approach 2:
The patent uses feedback from calibration marker positions to adjust the distortion correction parameters. By capturing images of calibration markers and analyzing their positions, the system obtains feedback about the actual alignment state and uses this information to refine the correction model, ensuring accurate distortion correction even when the lens center does not perfectly align with the image sensor center.
2Measurement precision
If traditional distortion correction methods are used without spatial geometric calibration, then the correction process is simple, but the accuracy decreases due to misalignment between lens center and image sensor center
Solution Approach 1:
The patent performs preliminary geometric calibration by capturing images of calibration markers at multiple positions before actual distortion correction. This preliminary action establishes the relationship between the lens center and image sensor center, allowing the system to compensate for assembly misalignment and achieve accurate distortion correction despite manufacturing tolerances.
Solution Approach 2:
The patent introduces calibration markers as intermediary elements to establish the geometric relationship between the lens and image sensor. These markers serve as mediators that enable the system to measure and compensate for misalignment, improving correction accuracy without requiring complex real-time adjustment mechanisms during actual image capture.
Data Source
AI summary
The present disclosure illustrates a lens distortion correction method to solve influence for distortion correction caused by an alignment error between a lens center and a center of image sensor unit during assembling. The present disclosure is characterized in that the spatial geometric calibration is incorporated with the lens distortion correction and different image centers are selected repeatedly when transformation relationship of image coordinates is used to perform the lens distortion correction, so as to correct the image center of the image to be corrected and enhance the accuracy of lens distortion correction.