Adaptive horizontal scaling method for speckle-assisted fringe projection profilometry

Area of Science:

• Optical Metrology
• 3D Reconstruction
• Computer Vision

Background:

• Phase-shifting methods are crucial for high-precision 3D measurements using fringe projection profilometry.
• Converting wrapped phase maps to absolute phase maps is essential for 3D data recovery.
• Speckle pattern-based phase unwrapping offers potential for rapid 3D measurements with minimal auxiliary patterns.

Purpose of the Study:

• To propose a novel speckle-assisted four-step phase-shifting method for enhanced 3D measurements.
• To address the phase ambiguity challenge in 3D reconstruction using speckle patterns.
• To improve the accuracy and efficiency of 3D profilometry, especially for complex surfaces.

Main Methods:

• A speckle-assisted four-step phase-shifting technique using five structured light patterns (four fringe, one speckle).
• An adaptive horizontal scaling method to enhance speckle matching accuracy on steep surfaces.
• A voting strategy based on phase-connected regions to reduce computational load.

Main Results:

• The proposed method effectively removes phase ambiguity in 3D measurements.
• Adaptive horizontal scaling significantly improves speckle matching accuracy.
• Experimental validation demonstrates superior performance with achieved accuracy of 0.21 mm.

Conclusions:

• The speckle-assisted four-step phase-shifting method provides a robust solution for accurate 3D measurements.
• The proposed techniques overcome limitations of traditional speckle-based phase unwrapping, particularly on challenging surfaces.
• This method holds promise for applications requiring fast and precise 3D reconstruction.