Phase-shifting profilometry resistant to varying ambient light.

Area of Science:

• Optical Metrology
• Image Processing
• Phase Measurement

Background:

• Conventional phase-shifting techniques assume constant ambient light (AL), limiting their use in variable lighting.
• Practical applications frequently encounter non-uniform and time-varying AL, causing significant phase errors.

Purpose of the Study:

• To propose a novel phase-shifting method robust to varying ambient light (AL).
• To enable accurate phase retrieval in challenging lighting conditions for optical metrology applications.

Main Methods:

• A new phase-shifting algorithm designed to cancel time-varying fringe backgrounds.
• Utilizing specially designed phase shifts and difference operations on captured fringe images.
• Suppression of both polynomial and non-polynomial AL variations.

Main Results:

• The proposed method effectively suppresses ambient light (AL) influence.
• Achieved significant reduction in phase errors, up to 84.03%, compared to existing methods.
• Demonstrated robustness and effectiveness in practical, complex lighting environments.

Conclusions:

• The novel phase-shifting method provides accurate phase retrieval under varying ambient light (AL).
• This technique enhances the reliability of optical measurements in real-world scenarios with challenging illumination.