Study On Applications Of Digital Holographic Imaging

Digital holographic imaging is an optical information processing technique which combines the traditional optical holography with modern electronics. The recording and reconstruction procedure is digitalized so that it meets the requirement for information acquirement, processing and transmission in modern times. The profile information of the objects’ surfaces can be easily obtained by analyzing the digital hologram captured on CCD or CMOS. It was widely studied by researchers since it appeared.In recent years, animated bomestic and international reshearches on digital holography have been developed. Applications of digital holographic imaging have been extended from profile measurement, interferometry and aberration compensation to vivo biological cells observation and three dimensional displays etc. Owing to the extensive application background of digital holographic imaging, theoretical and experimental researches have been carried out.In this paper, characteristics of digital holographic imaging are studied theoretically and experimentally. Digital reconstruction process, separation of the rebuilded images, image resolution, depth of field and depth of focus in Fresnel and Fourier transform digital holography are studied. On the basis of these principles, approaches to improve image quality are proposed and applications are introduced.This thesis involves following research works:(1) Resolution control of the reconstruction images in defocused Fourier transform digital holography is studied: theoretical model and image resolution of different defocused Fourier transform digital holography are deduced. The effectiveness in controlling image resolution in defocused Fourier transform digital holography is verified by experiment.(2) Digital holographic multi-plane imaging method with image fusion in DCT domain is proposed and reconstructed images of multi-planes can be obtained rapidly.Multi-plane imaging at arbitary reconstruction plane using quadratic distorted phase factor(QDPF) method is proposed. The meaning and principle of selection to parameters in this method is analyzed theoretically. Reonstrcuted images at multi-planes can be obtained by single Fresnel diffraction.(3) Profile measurement of micro objects are studied by digital holographic microscopy. The profiles of yeast cells and resolution plate are recorded by in-line digital holographic method. The conjugate noise is depressed by binary masks. Automatic phase compensation in off-axis Fresnel digital holographic microscopy by self-adapted quadratic distorted phase factor is also studied to improve image quality.(4) Based on digital mirror device(DMD) which serves as the key device, three dimentional displays with naked eyes with computer generated hologram(CGH) and digital hologram(DH) are studied. The binary holographic interfermetry is proposed to enhance diffraction efficiency of holograms for dynamic real world objects display.