Stereo Camera Calibration Through Windshield Refraction
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Solution Overview
Problem
Conventional stereo camera calibration methods fail to accurately calibrate absolute positional deviations caused by transparent bodies like windshields, leading to errors in three-dimensional coordinate calculations.
Innovation Solution
A calibration method and device that acquire and process photographic images of a calibration chart with and without a windshield to calculate and store correction parameters, allowing for the accurate calibration of absolute positional deviations in stereo camera systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stereo camera is installed inside a vehicle to photograph through the windshield, then durability against water and dust is improved, but absolute positional deviation in image coordinates occurs due to the transparent body
Solution Approach 1:
The patent performs preliminary calibration by photographing a calibration chart through the windshield before actual measurement operations. This preliminary action captures the distortion characteristics of the transparent body, enabling subsequent correction of absolute positional deviations in measured objects.
Solution Approach 2:
The patent changes calibration parameters by comparing image coordinates with and without the transparent body (windshield). Through this parameter comparison, the system calculates correction values that compensate for the distortion introduced by the transparent body, thereby improving measurement precision while maintaining the protective installation configuration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively calibrates absolute positional deviations, improving the accuracy of three-dimensional coordinate calculations and ensuring precise object positioning, even when imaging through a windshield.
Implementation Method 1
a transparent body such as a windshield... causes distortion on images photographed through the windshield
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
A calibration method is for a photographic device that photographs an object through a transparent body. The calibration method includes: acquiring a first photographic image by photographing the object without interposing the transparent body; acquiring a second photographic image by photographing the object through the transparent body; calculating an absolute positional deviation that indicates a deviation in coordinates of an image of the object due to the transparent body based on coordinates of an image of the object on the first photographic image and coordinates of an image of the object on the second photographic image; calculating a correction parameter for calibrating the absolute positional deviation; and storing the correction parameter in the photographic device.