Characterization of microlenses by transport of intensity equation

We present a reflection quantitative phase measurement system via transport of intensity equation (TIE). The proposed system includes an illumination collimation module and a microscopic imaging module. LED illumination is used in illumination module to avoid the effect of speckle noise. In imaging module, the 4f imaging system is formed by a long working distance objective and a lens. The constructed system was calibrated and the actual magnification of the system was 5x for 10x objective imaging. By moving the camera, two images at different defocused distances can be recorded and used for solving TIE to retrieve the phase of tested sample. Finally, the characterization of microlenses demonstrate the effectiveness of the proposed system.