Digital Holography Image Quality Improvement And Application

Digital holography is a novel holographic imaging technique, which integrates optical holography principle, computer technology and photoelectric technology. In digital holography, the hologram is directly recorded on a charge-coupled device (CCD) camera rather than a traditional holographic plate and the optical reconstruction is replaced by computer numerical reconstruction, so the holographic full process including recording, storage and reconstruction is entirely digital.In this paper, digital holographic imaging technology and its application for microscopy are studied. The main contents are as follows:1. Starting from the basic theory of Fresnel diffraction, the recording and reconstruction principles of digital holography are introduced. Comparative analyses on experimental recording conditions, information contents of hologram and system resolution are used for in-line and off-axis digital holographic systems.2. Based on the digital image processing technology, researches on eliminating zero-order diffraction and enhancing image quality are carried out for improving the quality of constructed image, and then how to improve the resolution of reconstructed images is discussed.3. The basic principle of digital holographic microscopy is discussed, and then the defocusing amount and system resolution are theoretically analyzed. Experimental study on onion cells is carried out and the resolution of in-axis system is tested by USAF 1951(0). Lastly the problem of noise in Gabor holographic microscopy is explored.