Objects Reconstruction By Digital Holography

Digital photosensitive electronic element is used in digital holography, such as CCD and CMOS camera. It records holograms in these instruments instead of silver holographic plate in traditional optical holography. The object is reconstructed exactly by the computer, which is used to simulate the reconstruction process of optical hologram.This paper starts with the theory of optical holography. It illustrates the basic principles of the recording and reconstruction of Fresnel digital holography. It also studies the depth of field and the depth of focus in the off-axis Fresnel digital holography imaging system, and relevant expressions have been deduced in detail. In the recording procedure of two-dimensional transparent object by Fresnel digital holography, plane wave and spherical wave illuminating object are used respectively, and the different experiment results have been analyzed. Single-beam illumination is always used to record three-dimensional opaque object by Fresnel digital holography. Due to the influence of the illumination condition, CCD only can receive a little weak scattered wave from the lateral surface of the object. So it can't reconstruct the multi-surface of the object clearly and brightly at the same time. To solve the problem, this article points out the technology of multi-beam illumination digital holography. It uses multi-beam to illuminate several surfaces of three-dimensional object during the experiment. In order to reduce speckle noise of the reconstruction image, bilinear interpolation and median filter is used to the image, and high quality reconstruction image of three-dimensional object is acquired.