A simple and practical jump error removal method for fringe projection profilometry based on self-alignment...

Area of Science:

• Optical Metrology
• 3D Measurement
• Computational Imaging

Background:

• Fringe projection profilometry is a robust and high-speed 3D measurement technique.
• Abnormal jump errors in phase unwrapping degrade measurement quality, especially in binary defocusing scenarios.
• Existing methods struggle with misalignment between wrapped phase and fringe order in significant defocusing.

Purpose of the Study:

• To propose a self-alignment technique (SAT) for eliminating phase jump errors in fringe projection profilometry.
• To address the challenge of misalignment in binary defocusing measurements.
• To achieve high-speed, accurate phase unwrapping without additional patterns or accuracy loss.

Main Methods:

• Analysis of grating changes and misalignment in fringe projection.
• Design of an assist-code for precise alignment with wrapped phase, even under significant defocusing.
• Application of the assist-code to correct misalignment and eliminate jump errors.

Main Results:

• The proposed SAT method successfully eliminates phase jump errors.
• Demonstrated effectiveness in simulations and experiments on complex textures and step-height objects.
• Maintained high speed and accuracy without requiring additional patterns.

Conclusions:

• SAT is a highly effective technique for removing phase jump errors in fringe projection profilometry.
• The method shows robustness even in significant defocusing conditions.
• SAT has potential applications in other phase unwrapping fields, such as color-based methods.