A carrier removal method in phase measuring deflectometry based on the analytical carrier phase description

Area of Science:

• Optical Metrology
• Surface Metrology
• Computer Vision

Background:

• Phase measuring deflectometry (PMD) uses fringe patterns to analyze specular object surfaces.
• Surface slope variations cause distortions in observed fringe patterns.
• Existing methods struggle with nonlinear carrier phases due to system geometry limitations.

Purpose of the Study:

• To develop an effective carrier removal method for PMD that addresses nonlinear carrier phases.
• To improve the accuracy and efficiency of surface slope measurements in PMD.
• To enable accurate measurements with a single object measurement.

Main Methods:

• Developed a novel carrier removal method based on analytical carrier phase description in PMD.
• Utilized theoretical analysis and experimental validation.
• Compared the proposed method with reference-subtraction and series-expansion techniques.

Main Results:

• The proposed method successfully removes nonlinear carrier phases in PMD.
• Achieved high accuracy in surface slope variation evaluation.
• Demonstrated the ability to perform measurements using only a single object, saving time.

Conclusions:

• The new carrier removal method enhances PMD's capability for accurate surface slope measurement.
• It overcomes limitations of existing methods by handling nonlinear carrier phases effectively.
• Offers a more accurate, time-saving, and efficient solution for specular surface analysis.