Vision Measurement Method Based on Plate Glass Window Refraction Model in Tunnel Construction

Area of Science:

• Optics and Vision Systems
• Robotics and Automation
• Geotechnical Engineering

Background:

• Tunnel construction environments necessitate explosion-proof vision systems with protective glass.
• Plate glass windows introduce optical refraction, invalidating standard pinhole camera models.
• Existing binocular vision systems fail due to refraction, impacting measurement accuracy.

Purpose of the Study:

• To develop a comprehensive solution for non-parallel plane refraction in vision measurement systems.
• To establish accurate imaging and triangulation models that account for refractive effects.
• To enhance the precision of depth and positioning measurements in challenging construction settings.

Main Methods:

• Established a non-parallel plane refraction imaging model using dynamic virtual focal length and the Rodriguez formula.
• Developed an epipolar constraint model specifically for independent refractive plane imaging.
• Proposed an independent refraction plane triangulation model to overcome measurement failures.

Main Results:

• The independent refraction plane triangulation model achieved a Root Mean Square Error (RMSE) of 0.3187 mm for depth errors after correction (down from 2.9902 mm).
• Positioning errors were reduced to an RMSE of 0.3465 mm post-correction (from 3.5661 mm).
• The proposed models effectively correct for refractive distortions in vision systems.

Conclusions:

• The developed models provide a robust solution for vision measurement systems operating behind refractive surfaces.
• Significant improvements in accuracy demonstrate the practical applicability in tunnel construction and similar environments.
• This research enhances the reliability and precision of vision-based measurements under adverse conditions.