数字全息显微系统的成像分辨率分析

根据成像理论和全息系统的点扩散函数,研究了数字全息显微系统的成像分辨率,给出了无预放大和有预放大情况下成像分辨率的表达式,指出了只有当CCD的成像分辨率等于或高于显微物镜(MO)的成像分辨率时,预放大数字全息系统的成像分辨率才取决于显微物镜的数值孔径(NA);反之,系统的成像分辨率则取决于CCD的数值孔径。采用无透镜傅里叶变换全息记录光路,对美国空军分辨率测试板进行了实验研究,结果表明再现像在水平和垂直方向的极限分辨率分别为3.91μm和4.38μm,与理论分析相吻合。对条纹物体进行了全息图的模拟记录和再现,结果与理论分析相一致。

Imaging Resolution Analysis of Digital Holographic Microscopy

According to optical imaging theory and the point spread function of digital holographic system, the imaging resolution of the digital holographic microscopy was investigated. The imaging resolution expressions of the digital holographic systems with and without pre-magnification were presented in details. With those formulas, it is clearly shown that only when the imaging resolution of CCD is not below the resolution of the microscope objective (MO), the imaging resolution of the whole system is dependent on the numerical aperture (NA) of MO. Otherwise, it is dependent on the numerical aperture of the CCD. Experimental imaging of US air force-resolution test target is performed using the lensless Fourier transform configuration. The experimental results that ultimate resolution of reconstructed image in horizontal direction and vertical direction is 3.91 μm and 4.38 μm respectively. Finally, recording and reconstructing of holograms for stripe object are stimulated , and results are corresponding with theoretical analysis.