Data processing for point-based in situ metrology of freeform optical surface

Area of Science:

• Optics and Optical Engineering
• Metrology and Measurement Science

Background:

• Advanced optical systems frequently utilize freeform surfaces.
• Point-based metrology is a common technique for measuring these surfaces.
• Accurate data processing, including coordinate matching and surface fitting, is crucial for metrology.

Purpose of the Study:

• To enhance the efficiency and accuracy of data processing for point-based freeform surface metrology.
• To develop and validate a robust method for coordinate matching and surface fitting.

Main Methods:

• A two-step coordinate matching strategy involving pre-adjustment and accurate adjustment.
• Development of an improved Newton iterative (INI) fitting algorithm for initial value generation and speed enhancement.

Main Results:

• The proposed two-step coordinate matching method improves both efficiency and accuracy.
• The INI fitting algorithm accelerates the surface fitting process.
• Simulations and experimental results confirm the method's correctness and feasibility.

Conclusions:

• The developed data processing techniques are effective for freeform surface metrology.
• This approach offers a reliable solution for accurate measurement of complex optical surfaces.