Gray-code-assisted phase unwrapping method based on phase information partition correction.

Area of Science:

• Optical Metrology
• 3D Reconstruction
• Computer Vision

Background:

• Gray code phase-shifting methods are prone to periodic phase jump errors.
• Stripe misalignment, unstable phase truncation, and order decoding errors degrade accuracy.
• Existing methods struggle with complex surfaces and preserving geometric details.

Purpose of the Study:

• To propose a robust phase unwrapping method for Gray code phase-shifting.
• To address and correct phase jump errors caused by various factors.
• To improve accuracy and detail preservation in 3D surface reconstruction.

Main Methods:

• A phase information partition correction strategy is employed.
• Wrapped phase is divided into three characteristic regions (K1, K2, K3) based on fringe order.
• Region-specific algorithms correct collapse-type, discrete, and jump-type errors.

Main Results:

• The proposed method effectively eliminates phase jump errors without additional projected patterns.
• It successfully processes highly discontinuous curved surfaces.
• Outperforms complementary Gray code and tripartite phase unwrapping in handling order decoding errors.

Conclusions:

• The method offers high robustness and edge preservation capabilities.
• It effectively eliminates jump errors without blurring genuine geometric details.
• Provides a superior solution for phase unwrapping challenges in optical metrology.