Dual-camera FOV Correction In TIE Dynamic Phase Imaging System

Transport of intensity equation(TIE)is applied to adaptive optics,characterization of micro-optics,nanomaterial,biomedical and other fields,which benefits from its advantages of non-interference and label-free.For TIE phase imaging,it is necessary to compute intensity differential along the light propagating direction,which is approximately replaced by the numerical difference between under-focus and over-focus images sequentially captured along the direction of light propagation.This procedure will reduce the acquisition speed.In order to realize TIE dynamic imaging,under-focus image and over-focus image can be simultaneously collected by using dual cameras,it can improve time efficiency without losing spatial resolution.However,there will be a misalignment between the over-focus image and under-focus image due to the misalignment of dual-camera installation and micro system matching,which will bring the error for differential calculation and result in inaccurate phase value by using TIE finally.This dissertation focuses on the field of view correction of dual-camera TIE dynamic phase imaging system,the main work includes two parts:1)The TIE phase imaging principle and imaging performance are introduced and analyzed.Specially,the boundary condition and defocus distance on TIE phase imaging are analyzed with experimental results.The tilt error of phase imaging caused by the boundary condition is corrected successfully.The effect of different defocusing distances on the phase recovery of TIE is discussed to select the optimal defocusing distance.2)Aiming at the mismatch of field of view in dual-camera dynamic phase imaging system,two rectify methods based on checkerboard calibration and micro-lens array calibration are proposed to eliminate the problem of misalignment with the sub-pixel aligning accuracy.The feasibility of method was verified by quantitatively imaging for a standard micro-lens array.Moreover,the quantitative phase imaging results for the dynamic Haematococcus pluvialis cells show that the dual-camera system after the field of view correction has a wide application prospect in bio-microscopy field.