Corner Marking for Incomplete Chessboard Calibration
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Solution Overview
Problem
Existing multi-camera systems face challenges in camera calibration due to the inability of each camera to capture a complete chessboard simultaneously, leading to difficulties in acquiring accurate camera parameters.
Innovation Solution
A corner marking method is introduced, which involves acquiring a target image of a chessboard with tagging squares, detecting corners, reconstructing the chessboard, and marking corners based on the identification and orientation of the tagging squares, allowing for camera parameter calibration even with incomplete or distorted captures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each camera in a multi-camera system captures a complete chessboard simultaneously for calibration, then accurate camera parameters can be acquired, but the system requires precise coordination and simultaneous capture which increases system complexity and is difficult to achieve in practice
Solution Approach 1:
The patent divides the chessboard into multiple tagging squares distributed across different regions. Each tagging square is independently detectable and contains identification information, allowing cameras to capture partial views rather than requiring complete chessboard visibility. This segmentation enables flexible multi-camera calibration without strict simultaneous capture requirements.
Solution Approach 2:
The patent allows cameras to capture only partial portions of the chessboard containing sufficient tagging squares for calibration, rather than requiring complete chessboard capture. The detection algorithm can work with incomplete chessboard views as long as enough tagging squares are visible to establish the coordinate system and perform calibration.
2Ease of operation
If traditional corner detection methods are used on incomplete or distorted chessboard captures, then the detection process is simpler, but orientation ambiguity of chessboard corners cannot be resolved
Solution Approach 1:
The patent introduces asymmetric tagging squares with unique identification patterns and orientation markers. Each tagging square contains encoded information about its position and orientation on the chessboard, allowing the system to distinguish between different corners and determine absolute orientation even when the chessboard is partially captured or distorted. This asymmetric design eliminates the 4-fold symmetry ambiguity of traditional chessboards.
3Measurement precision
If tagging squares with identification information are added to the chessboard, then orientation ambiguity is reduced and calibration accuracy improves, but the chessboard design and manufacturing becomes more complex
Solution Approach 1:
The tagging squares serve multiple functions simultaneously: they act as corner markers for detection, contain identification information for position identification, provide orientation markers for determining chessboard orientation, and enable robust detection under various lighting and viewing conditions. This multi-functionality reduces the need for separate components and simplifies the overall chessboard design despite the added capabilities.
Data Source
AI summary
A corner marking method, a parameter calibration method, and an electronic device are provided. The corner marking method includes: acquiring a target image, the target image including at least a portion of a target chessboard; detecting corners in the target image; performing a chessboard reconstruction based on detected corners to acquire a reconstructed chessboard; if the reconstructed chessboard contains one or more of tagging squares, acquiring one of the tagging squares of the reconstructed chessboard as a reference square; acquiring an identification and orientation of the reference square based on a tag of the reference square; marking corners in the reconstructed chessboard based on the identification and orientation of the reference square. Even if the target image does not contain a complete target chessboard, the corner marking method described in the present disclosure is still capable of marking corners in the target image.