Path-independent phase unwrapping method using zonal reconstruction technique

The phase unwrapping methods are widely used in the field of optical testing, which can be divided into the path dependant type and the path independent type. Generally, the former is faster but more sensitive to the noises, while the latter is more robust but suffers from the problems of slow iterative speed and high time consuming. To solve this problem, a new path independent phase unwrapping method was proposed, which was based on the zonal reconstruction technique. Using this method the wrapped phase in the rectangle pupil can be unwrapped directly without any iteration, and the sample-recombining acceleration strategy was designed to reduce the calculation time greatly which made the algorithm faster than other path independent methods. In addition, to unwrap the phase in the irregular pupil the Gerchberg type iteration was used which can converge in a few steps. The precision of the direct unwrapping for the regular pupil was validated by the simulations, as well as the effect of the acceleration strategy. Besides, the ability to process irregular pupil problem was demonstrated by unwrapping the phase obtained in the experiment.