多平面数字全息显微成像技术研究

Multi-Plane Digital Holographic Microscopy

为了同时获得多个平面的数字全息显微再现图像以延拓成像空间深度,提出一种多平面数字全息显微成像法。将预先设定参数的二次扭曲位相因子作用于实验记录的数字全息图,只需一次菲涅耳重建便可同时获得多个成像平面的清晰再现图像。首先依据菲涅耳成像系统的传递函数,推导了采用二次扭曲位相因子的成像传递函数,确定参数频域滤波的选取规则;然后将实验得到的数字全息图像进行频域滤波以消除直透光和共轭像;最后将二次扭曲位相因子作用于滤波后的全息图进行菲涅耳重建。与其他方法相比较,本方法只需一次重建就能同时得到多个平面的聚焦像,且重建距离可以任意选择,再现图像不受直透光和共轭像干扰。

In order to obtain multiple planes＇ reconstructed images of digital holographic microscopy simultaneously,a method for multi-plane imaging in digital holographic microscopy was proposed to extend the depth of imaging space.The quadratic distorted phase factor with pre-established parameters was used to act on experimental recorded digital hologram and the reconstructed images at multiple planes would be obtained simultaneously under single reconstruction.Firstly the imaging transfer function which used the quadratic distorted phase factor was deduced according to the transfer function of Fresnel imaging system and the rules of selecting frequency domain filtering parameters were determined.Secondly the experimental recorded digital hologram was utilized to conduct frequency domain filtering in aiming to eliminate zero-order diffraction and conjugate image.Finally the quadratic distorted phase factor was used to act on the filtered digital hologram to conduct Fresnel reconstruction.Compared with other methods,it needed single reconstruction to obtain multiple planes＇ in-focus images by the method and the reconstruction distance could be chosen in arbitrary,also the reconstructed images could be got without the interference of the zero-order diffraction and conjugate image.