G-code assisted fast phase unwrapping

Digital fringe projection (DFP) has proven effective for high-resolution and high-speed three-dimensional (3D) data acquisition. Established phase-retrieval methods for DFP such as multi-frequency and over-constrained multi-field-of-view unwrapping, can suffer from edge effects or depth-of-field constraints. This paper presents a novel phase unwrapping method, to our knowledge, that leverages the G-code information for an integrated digital fringe projection (DFP) system and three-dimensional (3D) printing system. After calibrating the transformation from the G-code coordinate system to the DFP coordinate system, a virtual reference phase map can be computed for each layer of G-code, and the reference phase map is then used to determine fringe order for each camera pixel. A computational framework is proposed to determine each printed layer geometry. Experimental results demonstrate that the proposed method outperforms the standard multi-frequency phase unwrapping method near sharp edges and produces identical results for inner areas, while achieving a minimum of 60× faster computation speeds. These results show promise for potential use cases in monitoring of 3D printed components.