Adaptive dual-exposure fusion-based transport of intensity phase microscopy.

Via the transport of intensity phase microscopy, quantitative phase can be retrieved directly from captured multi-focal intensities. The accuracy of the retrieved phases depends highly on the quality of the recorded images; therefore, the exposure time should be carefully chosen for high-quality intensity captures. However, it is difficult to record well-exposure intensities to maintain rather a high signal to noise ratio and to avoid over-exposure due to the complex samples. In order to simplify the exposure determination, here the adaptive dual-exposure fusion-based transport of intensity phase microscopy is proposed: with captured short- and long-exposure images, the well-exposure multi-focal images can be numerically reconstructed, and then high-accurate phase can be computed from these reconstructed intensities. With both simulations and experiments provided in this paper, it is proved that the adaptive dual-exposure fusion-based transport of intensity phase microscopy not only provides numerically reconstructed well-exposure image with simple operation and fast speed but also extracts highly accurate retrieved phase. Moreover, the exposure time selection scope of the proposed method is much wider than that based on single exposure, and even though there is an over-exposure region in the long-exposure image, a well-exposure image can still be reconstructed with high precision. Considering its advantages of high accuracy, fast speed, simple operation, and wide application scope, the proposed technique can be adopted as quantitative phase microscopy for high-quality observations and measurements.