Pre-distorted Camera Calibration Targets for Non-uniform Lenses
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optimization apparatuses for cameras with standard lenses are ineffective for lenses with non-uniform parameters, such as distortion, magnification, and relative illumination, as they deform images, making automated analysis and tuning challenging, and require software modifications that are often impractical for users.
Innovation Solution
A method to design custom optimization apparatuses where objects are pre-distorted to match the inverse of the lens's non-uniformity, allowing them to appear undistorted in images, compatible with existing software and usable across the entire field of view, including custom illumination for wide-angle lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing optimization apparatuses are used with lenses having non-uniform parameters, then the apparatus structure remains simple and standard, but the captured images become deformed and automated analysis software cannot recognize objects correctly
Solution Approach 1:
The patent applies preliminary action by pre-distorting the test chart pattern before it is captured by the lens. The distortion compensation is built into the test chart design itself, so that when the lens captures the image, the distortion is already compensated for. This allows standard automated analysis software to correctly recognize objects without requiring software modifications, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent creates a distorted copy of the standard test chart pattern that, when imaged through the non-uniform lens, produces an undistorted image. Instead of modifying the lens or software, a copied version of the test pattern with pre-applied inverse distortion is used, allowing standard apparatus and software to achieve accurate measurements.
2Measurement precision
If software modifications are made to accommodate lenses with non-uniform parameters, then object recognition accuracy improves, but the ease of operation deteriorates due to requiring source code access and modification skills
Solution Approach 1:
The patent uses a copied test chart pattern with pre-encoded distortion compensation. This copying approach transfers the complexity from the software side to the physical test chart side, allowing standard unmodified software to achieve accurate results. Users simply need to use the special test chart without any software modification skills, maintaining ease of operation while improving measurement precision.
Solution Approach 2:
The patent replaces the software-based distortion correction mechanism with a physical/optical mechanism. Instead of using software algorithms to correct distortion, the distortion compensation is embedded in the physical test chart pattern itself, substituting a mechanical/physical solution for a software solution and thereby simplifying user operation.
3Area of stationary object
If wide-angle lenses with non-uniform magnification are used, then the field of view increases, but objects cover significantly fewer pixels making image interpretation more challenging
Solution Approach 1:
The patent applies preliminary action by pre-distorting the test chart pattern to account for the wide-angle lens characteristics. The test chart is designed with distortion that compensates for the lens's non-uniform magnification, ensuring that even though objects cover fewer pixels, their shapes and positions are accurately represented, maintaining measurement precision across the expanded field of view.
Solution Approach 2:
The patent applies local quality by creating different distortion compensation patterns for different regions of the test chart. Since wide-angle lenses have varying magnification across different fields of view, the test chart incorporates location-specific distortion patterns that are tailored to compensate for local lens characteristics, ensuring accurate measurements throughout the entire expanded field of view.
4Device complexity
If existing optimization apparatuses are used with lenses having non-uniform parameters, then the apparatus configuration remains standard, but the lighting uniformity deteriorates especially for wide-angle lenses
Solution Approach 1:
The patent applies local quality by implementing location-specific lighting conditions that match the local distortion characteristics of the lens. Different regions of the test chart receive differently calibrated illumination to compensate for the non-uniform lighting patterns inherent in wide-angle lenses, maintaining lighting uniformity across the entire field of view without changing the overall apparatus configuration.
Data Source
AI summary
An optimization apparatus for a camera system having lenses with at least one non-uniform parameter and a method to design them is disclosed. When the non-uniform parameter of the lenses is the presence of optical distortion, the image of the objects inside the optimization apparatus are deformed. Embodiments of the invention allow designing of optimization apparatuses using 2D or 3D objects pre-distorted according to the exact distortion profile of the lens. When viewed by a camera system with a lens having optical distortion, the image of the pre-distorted apparatus appears undistorted, and can be automatically analyzed with existing software programs or be compared to existing images by human observers.