Carrier phase component removal: a generalized least-squares approach.

Area of Science:

• Optical Metrology
• 3D Surface Reconstruction
• Computational Imaging

Background:

• Fringe projection profilometry (FPP) is crucial for 3D object shape evaluation.
• Nonlinear carrier phase components arise from nonparallel illumination in FPP, complicating phase extraction.
• Accurate phase distribution is essential for reliable 3D surface measurement.

Purpose of the Study:

• To propose a general approach for removing nonlinear carrier phase components in FPP.
• To enhance the accuracy of 3D shape measurement under nonparallel illumination conditions.
• To develop a robust method applicable to diverse measurement system geometries.

Main Methods:

• Utilized a series expansion technique to approximate the nonlinear carrier phase function.
• Employed a least-squares method to estimate unknown coefficients of the series expansion.
• Conducted theoretical analysis based on divergent illumination with x-directional carrier fringes.

Main Results:

• Successfully demonstrated a general method for nonlinear carrier phase removal in FPP.
• The proposed approach accurately extracts phase distribution even with complex illumination.
• Extended the method to incorporate curved surface fitting for broader applicability.

Conclusions:

• The developed method effectively addresses the challenge of nonlinear carrier phase in FPP.
• This technique improves the precision and versatility of 3D profilometry systems.
• The approach is suitable for various measurement configurations, including those with curved surfaces.