Experimental demonstrations of the digital correction of complex wave errors caused by arbitrary phase-shift errors...

Area of Science:

• Optical Metrology
• Interferometry
• Digital Image Processing

Background:

• Phase-shifting interferometry (PSI) is susceptible to distortions from phase-shift errors.
• These errors introduce artifacts like double-frequency fringes and wave ripples in amplitude and phase maps.
• Existing methods struggle to fully correct these distortions, impacting measurement accuracy.

Purpose of the Study:

• To validate a digital correction method for amplitude and phase distortions in generalized PSI.
• To demonstrate the technique's effectiveness in suppressing artifacts caused by phase-shift errors.
• To improve the accuracy of amplitude and phase measurements in interferometric applications.

Main Methods:

• Development and simulation of a digital correction algorithm for PSI.
• Extension of the method to generalized PSI configurations.
• Optical experiments using plane waves, spherical waves, and a glass sample for validation.

Main Results:

• Experimental results confirm the theoretical analysis of the digital correction method.
• The method successfully suppresses double-frequency fringes in amplitude maps.
• Distortions such as wave ripples and wall-like structures in phase maps are effectively eliminated.
• Reduction in invalid pixels facilitates more robust phase unwrapping.

Conclusions:

• The digital correction technique significantly improves the accuracy of amplitude and phase measurements in PSI.
• The method is robust and applicable to various interferometric setups and object types.
• This approach offers a reliable solution for mitigating phase-shift errors in interferometry.