An extrapolation-based method for improving the accuracy of phase retrieval with the transport of intensity equation

Single-shot quantitative phase imaging (QPI) using wavelength multiplexing

“…where λ means wavelength of the light, I z   is the intensity axial derivative,  is gradient operator, and I and φ respectively represents intensity and phase of imaging plane. To achieve TIE phase retrieval, two intensity images (one in-focus and the other at defocus) are need to be obtained [8][9][10], which requires the camera to capture images from two different positions on the axis. This greatly limits its application of TIE in dynamic measurement and imaging.…”