Automatic spatial filtering to obtain the virtual image term in digital holographic microscopy.

The main factor that limits the quality of an image reconstructed by the process of spatial filtering in digital holographic microscopy is discussed. A spatial filter determined by the distribution of the spectrum of the virtual image is designed automatically for real time dynamic analysis of a micro-object, and an optimal reconstructed phase image can be obtained. An experiment of a holographic image with an onion specimen is presented to prove the validity of this approach. Comparing the numerical reconstruction of the hologram by employing different spatial filters with the automatic spatial filtering shows the superiority of the automatic spatial filtering method, and it is suitable for dynamic and automatic analysis.