改善数字全息显微术分辨率的几种方法

从理论和实验上研究了数字全息显微术的分辨率问题。通过分析几种不同数字全息记录光路对记录介质空间分辨率的要求表明，无透镜傅里叶变换全息光路对CCD的空间分辨率要求最低，最能充分利用CCD的带宽；再现像面的空间分辨率在不同方向上的不一致，会导致再现像在空间分辨率高的方向上相对展宽，而在空间分辨率低的方向上相对压缩；再现像的横向分辨率主要由CCD所能记录的物体的最高空间频率决定，它随CCD的尺寸和空间分辨率的提高及记录距离D的减小而提高。给出了消除再现像畸变的方法及实验结果，并提出了3种改善横向分辨率的方法。

Methods of Improving Resolution of Digital Holographic Microscopy

Resolution of digital holographic microscopy was theoretically and experimentally researched.Three important conclusions are achieved:1) By analyzing the demand for spatial resolution of recording medium in different digital holographic recording setups,it shows that lensless Fourier transform holography can relax the requirement of spatial resolution and use the full spatial bandwidth of the CCD sensor.2) Because of the differences of spatial resolution of image planes in different directions,reconstructed images can be relatively extended in the direction of high spatial resolution and reduced in the direction of the low one.3) Lateral resolution of the reconstructed images is mainly determined by the highest spatial frequency of digital holograms recorded by CCD,and increases with the larger CCD size,the higher spatial resolution of the CCD sensor,and the shorter recording distance.Furthermore,the method and experimental results of eliminating the aberration of reconstructed images were presented,and three approaches to increase the lateral resolution of the reconstructed images were investigated.