Color fringe-projected technique for measuring dynamic objects based on bidimensional empirical mode decomposition.

Area of Science:

• Optical Metrology
• 3D Reconstruction
• Dynamic Measurement

Background:

• Accurate 3D measurement of dynamic objects is challenging.
• Existing techniques often struggle with large discontinuities or isolated surfaces.
• Color fringe projection offers potential for enhanced data acquisition.

Purpose of the Study:

• To develop a robust technique for measuring dynamic objects.
• To overcome limitations of single-frequency methods in complex scenarios.
• To enable high-resolution 3D surface recovery from a single snapshot.

Main Methods:

• A triple-frequency color fringe projection technique was developed.
• Fringe patterns with a 1:3:9 frequency ratio were encoded in RGB channels.
• Bidimensional empirical mode decomposition (BEMD) was used for crosstalk decoupling and fundamental frequency extraction.
• A three-step phase unwrapping strategy was employed for height distribution recovery.

Main Results:

• The technique successfully decoupled crosstalk between color channels.
• Accurate unwrapped phase distribution was retrieved from high-frequency fringes.
• Object height distributions were recovered for dynamic objects with large discontinuities.
• The method demonstrated suitability for spatially isolated surfaces.

Conclusions:

• The triple-frequency color fringe projection technique enables accurate 3D measurement of dynamic objects.
• Single-snapshot acquisition makes it ideal for transient phenomena.
• The BEMD-based crosstalk decoupling is effective for complex fringe patterns.