Stereo Camera Calibration Using Multi-Depth Inspection Tools
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Solution Overview
Problem
Conventional stereo camera calibration techniques require a large and restricted environment to achieve high accuracy, making it difficult to calibrate the whole image effectively, especially for vehicle-mounted cameras with wide angles of view.
Innovation Solution
An image processing apparatus and method that uses a pair of cameras with a correction parameter determination unit to calculate correction parameters by imaging two inspection tools at different distances, allowing for accurate calibration of the entire image within a smaller and more flexible calibration environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single distant subject is used for calibration, then the calibration environment space is wide, but the measurement precision and alignment accuracy deteriorate
Solution Approach 1:
The calibration target is segmented into multiple inspection tools positioned at different distances from the camera. Instead of using one distant target, the system divides the calibration space into multiple zones with inspection tools at varying distances, allowing simultaneous calibration of different image regions with appropriate precision requirements.
Solution Approach 2:
Different regions of the image are assigned different quality requirements. The center region uses inspection tools at farther distances with relaxed precision requirements, while peripheral regions use inspection tools at closer distances with higher precision requirements. This local differentiation optimizes overall calibration accuracy without requiring uniformly wide environment space.
2Area of moving object
If a wide angle of view is used, then the imaging coverage is expanded, but the calibration environment restriction increases
Solution Approach 1:
The calibration approach transitions from a single-plane distant target to a multi-depth arrangement of inspection tools. By adding the distance dimension as a variable, the system can calibrate wide-angle images without requiring a uniformly wide environment, as inspection tools at different depths provide reference points across the expanded field of view.
3Measurement precision
If the subject distance is exactly adjusted, then the parallax alignment is accurate, but the calibration operation complexity increases
Solution Approach 1:
The system uses the known geometric relationships and predetermined positions of multiple inspection tools to automatically determine correction parameters through computational algorithms. This self-calibration approach eliminates the need for manual distance adjustment and alignment operations, achieving high parallax alignment accuracy without increasing operational complexity.
Data Source
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AI summary
An image processing apparatus, comprises: a first acquisition unit that acquires a first imaged image and a second imaged image, the first imaged image being obtained by imaging a first subject (101) located apart from a stereo camera (10) including a first camera and a second camera by a first distance (x1) by the first camera, the second imaged image being obtained by imaging the first subject by the second camera; a second acquisition unit that acquires a third imaged image and a fourth imaged image, the third imaged image being obtained by imaging a second subject (102) located apart from the stereo camera (10) by a second distance (x2) smaller than the first distance by the first camera, the fourth imaged image being obtained by imaging the second subject (102) by the second camera; and a correction parameter determination unit that determines correction parameters for correcting an imaged image obtained by the imaging by the first camera or the second camera on the basis of the first imaged image and the second imaged image in relation to a first image area indicating a central area of the imaged image, and on the basis of the third imaged image and the fourth imaged image in relation to a second image area indicating an image area other than the central area of the imaged image.