Analysis of Depth of View and Focus of Digital Holographic Imaging System
数字全息成像系统的景深和焦深分析

Based on the Fresnel diffraction theory, the depth of view (DOV) and the depth of focus (DOF) of the digital holographic system are analyzed. The approximate expressions of the DOF of the different holographic recording configurations are deduced. The results show that the DOV and DOF of the digital holographic imaging system are related to the optical wavelength and the numerical aperture of the CCD camera and to the offset of the reference light wave. With both the same recording distance and parameter of CCD, the DOF of the off-axis Fresnel holographic system is found larger than that of the in-line Fresnel digital holographic system. The DOF of off-axis lensless Fourier digital holographic system with symmetrical offset of reference wave is slightly smaller than that of the system without symmetrical offset. Moreover, in digital holographic microscopy, the DOF of off-axis lensless Fourier digital holographic system is larger than that of in-line Fresnel digital holographic system. The computer simulation results confirm the validity of the theoretical analysis.