利用小尺寸电荷耦合器件实现数字全息高分辨成像

为了在降低数字全息显微成像系统成本的同时实现高分辨成像，对像面数字全息显微术的记录与再现过程进行了理论分析，结合系统的点扩散函数，对该系统的横向分辨率进行了分析. 得到了如下结论：像面数字全息显微系统的横向分辨率对电荷耦合器件（CCD）光敏面尺寸变化不敏感；对于常见的CCD 器件，其像元尺寸的变化对该系统的横向分辨率影响甚微. 此外，对像面数字全息显微系统的成像特点进行了分析，结果表明：利用像面数字全息系统可以实现物体信息的完整记录与再现，其成像分辨率及像质优于预放大数字全息系统. 利用搭建的数字全息实验记录系统，从强度及位相两方面对理论分析结果进行了验证，实验结果表明了理论分析的正确性. 关键词： 像面数字全息术 横向分辨率 点扩散函数 小尺寸电荷耦合器件

High-resolution digital holographic microscopy realized by small size CCD camera

In order to achieve high-resolution imaging by reducing the cost of digital holographic microscopy system, the recording and reconstruction process of image-plane digital holographic system (IPDHS) and its point spread function are analyzed. Then, the determination factor of lateral resolution of IPDHS is investigated. It is concluded that the dependence of lateral resolution of IPDHS on the photosensitive surface size of the recording device is very weak, which is completely different from the common knowledge that the lateral resolution of digital holographic imaging system can be improved by using large size recording device. Then the imaging characteristics of an IPDHS are analyzed. The results show that the information about the tested object can be completely recorded and reconstructed by image-plane digital holography, and that the lateral resolution of IPDHS is higher than that of pre-magnification digital holography. Two IPDHS with plane and spherical reference wave are built. The experimental results are in accordance with the theoretical analysis.
Keywords： image-plane digital holography lateral resolution point spread function small size CCD