Fresnel Digital Holographic Imaging Technology To Study

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.The thesis gives a brief introduction to basic theory of optical holography at first. Then the optimal-recording condition has been analyzed on the basis of digital Fresnel hologram, and related theoretical derivation and experiments have been conducted by means of circular object as example.To eliminate the zero-order image in off-axis hologram experiment,the author applies three different digital processing methods to hologram, and compares the elimination of the zero-order image and image contrast in experiments.The thesis discusses the affection of speckle on digital holographic imaging,proposes zero-padding method to improve image quality, and compares the feasibility of zero- padding method for holographically recording coin's rough surfaces of different diameters.The thesis introduces pre-amplification digital Fresnel holographic imaging to experiment of onion cells and resolution test target as recording object respectively, suggests that frosted glass plate be inserted in the recording optical path so as to improve image quality of resolution test target, experimental results were shown finally.