Frequency-domain searching algorithm in deflectometry for measuring the surface of a transparent planar element

Area of Science:

• Optics
• Metrology
• Surface analysis

Background:

• Deflectometry is crucial for optical surface metrology.
• Existing frequency-domain methods face limitations in separating surface reflections.
• Accurate measurement of transparent materials with reflective surfaces is challenging.

Purpose of the Study:

• To introduce a novel frequency-domain searching algorithm in deflectometry (FSAD).
• To overcome limitations of current frequency-domain techniques.
• To enable complete measurement of optical surfaces, including front and back reflections.

Main Methods:

• Encoding specialized multi-frequency fringe patterns.
• Employing a correlation searching algorithm for analysis.
• Applying FSAD to deflectometry measurements.

Main Results:

• FSAD successfully separates front and back surface reflections.
• Complete measurement data from reflective surfaces can be obtained.
• Experimental verification on a 10 mm thick window glass sample.

Conclusions:

• FSAD offers an advancement in frequency-domain deflectometry.
• The algorithm enhances the ability to acquire comprehensive optical data.
• FSAD shows potential for precise metrology of optical components.