Accurate fast quantitative phase imaging based on accelerative iterative transport of the intensity equation solution.

As a simple and widely used quantitative phase imaging (QPI) approach, the transport of intensity equation (TIE) is plagued by accuracy and applicability issues due to the limitations of conventional solution algorithms. To address these problems, we present an accurate fast QPI method using an accelerated iteration-based TIE solution. In this method, a gradient acceleration iterative solution is constructed by TIE itself. In this manner, the restrictions in TIE ("phase discrepancy" and "phase singularity" issues) are bypassed, resulting in a fast convergence TIE numerical algorithm with great applicability. In addition, by using high-accurate multi-plane intensity derivative estimation result as initial iteration value, the accuracy and noise robustness of phase reconstruction are significantly improved. Finally, an accurate, fast, and widely applicable QPI can be achieved. Experiments on various phase objects, including phase plates and living cells, demonstrate the accuracy, applicability, and real-time measurement ability of our method. Our method provides a general TIE algorithm for accurate real-time QPI.