An enhanced multimode phase imaging method based on the transport of intensity equation

Label-free biological cell imaging relies on rapid multimode phase imaging of biological samples in natural settings. To improve image contrast, phase is encoded into intensity information using the differential interference contrast (DIC) and Zernike phase contrast (ZPC) techniques. To enable multimode contrast-enhanced observation of unstained specimens, this paper proposes an improved multimode phase imaging method based on the transport of intensity equation (TIE), which combines conventional microscopy with computational imaging. The ZPC imaging module based on adaptive aperture adjustment is applied when the quantitative phase results of biological samples have been obtained by solving the TIE. Simultaneously, a rotationally symmetric shear-based technique is used that can yield isotropic DIC. In this paper, we describe numerical simulation and optical experiments carried out to validate the accuracy and viability of this technology. The calculated Michelson contrast of the ZPC image in the resolution plate experiment increased from 0.196 to 0.394. This paper proposes an enhanced multimode phase imaging method based on the TIE to perform multimode contrast-enhanced observation of unstained specimens. First, quantitative phase results of biological samples are obtained by solving the TIE, and then optimal ZPC and isotropic DIC images are obtained. Application of the algorithm to real and simulated objects shows significant feasibility and accuracy. Experiments on MCF-7 cells resulted in multimode images of cells with structures not visible in the raw intensity images. The algorithm is simple to implement and can be combined with traditional optical microscopy. image