Simultaneous All-Parameters Calibration and Assessment of a Stereo Camera Pair Using a Scale Bar

Area of Science:

• * Computer Vision
• * Photogrammetry
• * Metrology

Background:

• * Accurate camera calibration and orientation are crucial for expanding 3D vision and photogrammetry applications in large volumes.
• * Existing methods can be complex and prone to systematic errors, particularly concerning scaling.

Purpose of the Study:

• * To propose a novel, user-friendly method for simultaneous calibration, orientation, and assessment of multi-camera 3D measurement systems.
• * To enhance the accuracy and reliability of 3D measurements in large-scale environments.
• * To reduce systematic errors associated with scaling in self-calibrating bundle adjustment.

Main Methods:

• * Development of a simultaneous self-calibrating bundle adjustment incorporating 3D point and length arrays generated by a moving scale bar.
• * Estimation of relative exterior parameters using the five-point relative orientation method.
• * Optimization of interior, distortion, and relative exterior parameters using bundle adjustment with distance constraints.

Main Results:

• * Achieved Root Mean Square Error (RMSE) for length measurement below 0.25 mm.
• * Attained relative precision exceeding 1/25,000 for a two-camera system in a 12m x 8m x 4m volume.
• * Demonstrated ease of operation and significant reduction in systematic errors compared to state-of-the-art methods.

Conclusions:

• * The proposed method offers a practical and accurate solution for calibrating and orienting multi-camera systems in large measurement volumes.
• * It provides robust internal precision and external accuracy assessment.
• * The technique is effective in mitigating systematic errors, making it a valuable advancement for 3D vision and photogrammetry.