为了解决现有数字全息显微系统中高分辨率与大记录视场无法同时兼得的问题,提出了一种在不牺牲分辨率的前提下拓展数字全息显微记录视场的方法.该方法中运用了波长不同、偏振态不同的四路相互不相干的探测物光,同时探测被测样品四个相邻的不同区域,并使这四束探测物光分别与其相应的参考光相干,在记录面上同时记录下含有被测样品不同区域信息的复合全息图.将获得的复合全息图经过频谱变换和数字滤波,分别重构出所记录区域的振幅和相位分布.最后通过图像拼接和图像融合技术,可实现接近原记录视场四倍的大视场数字全息显微记录.该方法在测量过程中无需移动记录装置、光源和被测样品,单次曝光即可实现,实验结果验证了本文所提方法的可行性.
We present a method to expand the record field of view in the recording process of digital holographic microscopy systems without loss of resolution. A series of incoherent sub-holograms covering different regions of sample can be recorded in a single frame of the CCD synchronously based on wavelength and polarization multiplexing. The reconstructed images can be obtained with information about different parts of the sample. Thus, the synthetic reconstructed image with a wider field can be achieved by image stitching and fusion technology without any form of scanning. Based on single-exposure working principle, this approach can be used for real-time recording of the dynamic samples without moving CCD, point source and tested samples. Experimental results show that the final synthetic image produced by the system in this paper can be achieved to be close to four times as large as the original record field of view with original resolution.