Three-Dimensional Reconstruction of Moving Objects with High Reflectivity Based on Dual-Frequency Unwrapping

Phase-shifting profilometry is widely applied in various fields because of its high measurement accuracy and robustness. However, the necessity to project multiple fringe patterns onto the object's surface requires the object to remain stationary during the measurement process. Conversely, overexposure occurs and its position changes with the object's motion during the reconstruction of the highly reflective moving objects, which poses a measurement challenge. Hence, this study proposes an algorithm for measuring highly reflective moving objects. The change in the overexposure position with the object's motion means that not all stripe patterns have overexposure. First, a dual-frequency fringe pattern is projected onto a moving object's surface, and photos are taken. Second, the overexposed areas in all fringe patterns are identified, and the nonoverexposed fringe patterns at each point on the object are recorded. Phase extraction is again performed based on the nonoverexposed fringe patterns with nonequidistant phase shifts to achieve a dual-frequency phase distribution. Finally, motion compensation is applied to the dual-frequency phase distribution, and correct unwrapping is achieved based on the dual-frequency unwrapping algorithm, thereby completing the three-dimensional reconstruction of highly reflective moving objects. The experimental results show that the algorithm effectively reduces measurement errors due to highly reflective moving objects and has a high industrial application value.