Research On Resolution Of Reconstructed Image Of Digital Holography

Digital holography is a mix of optical holography, photoelectrical imaging technology and computer technology. It utilizes charge coupled device (CCD) to record holograms instead of silver print which is used for the recording medium in optical holography and use computer programming to reconstruct the original object numerically. The digital holography pick up the reconstruction time by full numerical recording, storing and reconstruction process, and we can use mature digital image processing technology to dispose the reconstructed image to make it clear.In this paper, the principle of digital holography based on the optical holography is introduced, and the numerical model of reading and reconstruction process is built. The location of reconstructed image and the conditions of experiments are elicited, such as the range of recording distance and angle between the object light and the reference light. Then the reconstructed arithmetic of digital holography is introduced.The processing technology of reconstructed image which is used to delete the zero-order spot and conjugate image is researched, and the method which can improve the resolution of digital hologram.(1) In this paper, the digital image processing methods such as spectrum filtering, spatial filtering, Laplacian transformation and HRO subtraction are introduced. Then prove and compare their efforts on filtering the zero-order spot and conjugate image.(2) Introduce the principle of synthetic aperture digital holography in detail. The two synthetic aperture digital holography recording systems: by translation of CCD and translation of object are designed under existing condition of our laboratory. Based on intensity correlation theory, the method of sub-digital hologram combination is researched. The synthetic aperture digital hologram obtained by combination of the sub-digital hologram is reconstructed, the reconstruction result shows that the reconstruction image resolution can be improved by synthetic aperture digital holography.