Hybrid-quality-guided phase fusion model for high dynamic range 3D surface measurement by structured light technology

Using structured light to measure the 3D shape of a high dynamic range (HDR) surface has been always a challenging problem, and fusion of multi-group images with different exposures is recognized as an effective solution. It tends to select the phase with unsaturated and maximum gray intensity as the final phase, which has two problems: 1) the selection criteria are too simple to fully evaluate the phase quality, and 2) it is affected by the image noise, camera's nonlinear response, local reflection and other factors and the phase with the best quality among the initial phases may also have an error. Aiming to solve these issues, this paper presents a hybrid-quality-guided phase fusion (HPF) model. In this model, a hybrid-quality measure is first proposed to evaluate the phase quality more comprehensively. Then, all initial phases are weighted and fused under the guidance of the hybrid-quality measure to obtain a more accurate phase as the final one. Through this model, a more complete and accurate 3D shape of the HDR surface can be reconstructed, and its validity has been verified by several experiments.