数字全息显微系统结构参量对再现像质的影响

为了获取高质量的数字全息显微再现像,分析了同轴相移数字全息显微系统结构参量对再现像质的影响.首先经过计算得出理想成像时,像空间物光波频率完全由物体面形结构频率和系统放大倍率决定.然后基于显微成像时物光波的所有频率分量都应该被有效记录的分析,得出在同轴相移系统中放大倍率必须使物光波的空间频率缩小到满足采样要求|并得出在相同的放大倍率下记录距离会影响有效记录的物体尺寸,记录器件离开像平面的距离越小,有效记录的物体尺寸越大,在像平面上时有效记录的物体尺寸最大.计算机仿真和光学实验都证明了上述结论的正确性.

Effect of System Parameters on the Reconstructed Image Quality in Digital Holographic Microscopy

The effect of system parameters on the reconstructed image quality in in-line digital holographic microscopy was studied.Firstly the spatial frequency of object wave was computed.Under the assumption of perfect imaging,the spatial frequency of object wave in the image space was completely determined by the frequency of the surface structure of the measured specimen and the magnification of the imaging system.Then,a suitable magnification must be designed so that the spatial frequency of object wave in the image space could satisfy the sampling capacity,based on the analysis that all the spatial frequency components of object wave should arrive at the recording plane and be effectively recorded in order to acquire the reconstructed image with high quality.And the recording distance affects on the object size which can be effectively recorded.When the magnification was the same,the size became larger with the decrease of the recording distance.Both the simulation and optical experiments validate the correctness of the proposed analysis.