Real-Time Complex Object 3D Measurement

Real-time complex object 3D measurement based on digital fringe projection has a huge potential for applications in many areas, including reverse engineering, inspection, entertainment and social security. We describe a real-time complex object 3D shape measurement technique based on viewpoint-coded structured light technique and phase-shifting technique. Previously, unambiguous reconstruction codes could only be encoded spatially or temporally. The viewpoint coding, in contrast, allows for depth reconstruction without making any spatial or temporal continuity assumptions about the scene. With k camera positions, the viewpoint-coded structured light method can distinguish between 2^k depths. For complex object 3D measurement, it is still limited. So, in this work, we combine the three-step phase-shifting method and the viewpoint-coded method to reconstruct 3D points of the complex object in realtime. By choosing three appropriate camera positions, three different frequencies fringe images can be captured. Thereby, a famous multifrequency heterodyne principle can be used for unwrapping the phase value obtained from the three-step phase-shifting method. A prototype system is developed to demonstrate this novel hybrid method. The experimental results show that this method can reconstruct the 3D shape of complex object in real-time.