Study Of Record And Reconstruction Of Off-axis Digital Holography

Digital holography is created by the combination of optical holography, the technique of computer and photoelectron. At present, the digital holography is becoming an active research topic in the filed of optical holography. In digital holography, CCD sensor is used to record holograms instead of traditional photosencitizer plate. The holograms are stored in a computer. And also, the process of reconstruction of object wave field is simulated by computer. In contrast to traditional optical holography, digital reconstruction can eliminate the effects of zero order and conjugate image, as well as noise produced during recording. The process of digital holography is more flexible and suitable to analyze and measure the experiment result quantitively. Moreover, it helps to store and process images digitally, cut down the cost, and so on. Additionally, the object wavefront reconstructed digitally is very useful for observing the result of measured object and further research.The technique of numerical reconstruction was remarkablely developed in the 90's of 20th century. Then, this technique was applied in profile recognization, deformation detection, vibration measurement and bio-particles field monitoring. The work that the object wavefront is recorded and reconstructed could be considered as the information's transformation, storage and reacquisition. These just were what we called the processing of information. It is the important part of the science of information, which plays an extremely important role in the modern optics.On the basis of theoretical analysis of digital holography, primary study is carried out through computer simulation and experiments. The main work is as follows:Firstly, on the basis of off-axis Fresnel hologram, the principles of optical holography and digital holography are introduced. Besides of these, the theoretical analysis such as recording condition, numerical reconstruction and the related digital image processing methods are made. Secondly, starting from the digital holography experiment, an experimental plan is designed with respect to the record of Fresnel hologram. Meanwhile, the recording condition under present CCD's resolution is discussed.Finally, the image of an object is successfully reconstructed by using of digital holograms recorded by CCD through numerical reconstruction program. Moreover, the result of the experiment validates the theoretical analysis and the experiment plan of digital holography.In this dissertation, the comparison between optical holography and digital holography is made. The reconstructing algorithm and recording condition about digital hologram are discussed. Some fundermental works concerned with digital holography are managed to do. This study will be helpful for further research toward digital holography in the future.