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

To address periodic phase jump errors caused by stripe misalignment, unstable phase truncation information, and order decoding errors in the Gray code phase-shifting method, a phase unwrapping method based on phase information partition correction is proposed. The core of this method lies in a partition governance strategy: First, based on the decoded fringe order K, we roughly determine the range of each period of the wrapped phase. Then, guided by the wrapped phase values within each period, the fringe order K is divided into three characteristic regions (K₁, K₂, and K₃). Subsequently, dedicated correction algorithms are designed for each region's unique error patterns-collapse-type errors in the K₁ region, discrete errors in the K₂ region, and jump-type errors in the K₃ region. Experimental results demonstrate that the proposed method can effectively eliminate jump errors without requiring additional projected patterns. It remains effective in eliminating jump errors even when processing highly discontinuous curved surfaces. Compared with pre-avoidance methods such as complementary Gray code and tripartite phase unwrapping, this method successfully solves jump errors caused by order decoding errors that those methods cannot handle. Compared with post-correction methods such as median filtering, this method eliminates jump errors without blurring genuine geometric details, demonstrating high robustness and edge preservation capability.