LAUSR

Abstract In this paper, we propose an analytical phase retrieval approach applying only phase modulations in the region isolated from the object to be measured. This approach employs a series of intensity-only measurements and can accurately and conveniently achieve phase recovery in the range of [0, 2π) once a reference phase is calibrated in advance. To improve the robustness of the algorithm, this paper yields an over-determined method (OM) by extending the phase modulation procedure from 3 steps into n steps. The algorithm's exact phase retrieval ability, the influence of key parameters’ disturbance on solving precision, and the theory of robustness improvement are all verified through numerical simulations. It is noteworthy mentioning that the robustness enhancement method performs well–improving the phase retrieval accuracy efficiently. Also, an experiment is undertaken and the results are satisfactory, demonstrating the core of our approach and showing the capability of OM.