BimodalPS: Causes and Corrections for Bimodal Multi-Path in Phase-Shifting Structured Light Scanners.

Area of Science:

• Computer Vision
• Optical Metrology
• 3D Imaging

Background:

• Structured light illumination is a key 3D scanning technique.
• Multi-path interference, where a camera pixel receives light from multiple projector positions, complicates accurate depth measurement.
• Bimodal multi-path occurs at step edges, causing a single pixel to capture light from two distinct surfaces.

Purpose of the Study:

• To develop a general mathematical model to address bimodal multi-path issues in phase-measuring-profilometry (PMP) scanners.
• To enable accurate depth measurements by analyzing the interference between dual light paths.
• To improve the precision and reliability of 3D scanning in challenging scenarios.

Main Methods:

• Developed a mathematical model to quantify constructive and destructive interference between two light paths.
• Utilized interference patterns to separate the dual light paths within a single camera pixel.
• Implemented a phase-shifting or phase-measuring-profilometry approach for decoupled depth measurements.

Main Results:

• The proposed model effectively measures and utilizes interference between dual light paths.
• Successfully separated the two light paths, enabling two independent depth measurements.
• Demonstrated significant performance improvement over state-of-the-art methods in simulations and real-world tests.

Conclusions:

• The novel mathematical model provides a robust solution for bimodal multi-path interference in structured light 3D scanning.
• This approach enhances the accuracy of 3D reconstruction, particularly at object edges.
• The validated algorithm offers a significant advancement for phase-measuring-profilometry techniques.