Three-dimensional profile measurement based on modified temporal phase unwrapping algorithm

Phase unwrapping is an important part of the three-dimensional profile measurement. It determines the measurement accuracy of the system. For the phase of the projection gratings on each object or among separated objects are often discontinuous, a modified temporal phase unwrapping algorithm with the exponent of 4 and changing phase-shifting step is proposed. Comparing with the traditional exponential sequence temporal phase unwrapping algorithm with the exponent of 2, the proposed algorithm is simpler. When the same number of fringes is projected, the measurement accuracy using the proposed algorithm is greatly improved. Computer simulations and experiments prove the effectiveness of the method.