Algorithm Study Of Computer-generated Hologram Used To 3-D Display

In recent years, the research of 3-D display becomes more and more popular. Computer-generated holography (CGH) can keep complete information of object waves, and the CGH has fewer requirements on the environment conditions than optical holography. Therefore, producing hologram of 3-D objects quickly by computer-generated holography and through the holographic reconstruction to achieve the 3-D display has been a significant work.This work includes the following subject:At first, the development history of optical holography is reviewed. The present advance of the computer-generated holographic technology and 3-D display is introduced briefly. The advantages and disadvantages are compared among the Virtual Reality technology.3-D technology and holography toward implementing methods and redisplay quality.Secondly, three algorithms of the Fresnel diffraction integral are discussed. The basic theory and coding methods of computer-generated holography are described in detail. After simulation on a computer by programming in Matlab, the merit and shortage of these methods mentioned above have been compared with each other. Moreover, the in-line hologram and off-axis hologram are described, and the difference and connection between these two kinds of holographic technology are presented. Programming simulation on a computer is performed in Matlab to prove the algorithm. The paper focuses on the research of the methods to display a 3-D object by computer-generated holography, which are point-source method, tomography method and multi-angle projection method. Using point-source method and tomograph) method, a computer-generated hologram of a simple 3-1 object is generated, and rcconstruction of the 3-D object is achieved on computer by Matlab programming. The approaches of recording and reconstructing a 3-D object in these two ways have been verified.Finally, two computer-generated holograms in point-source method and tomography method are employed as input of a spatial light modulator to accomplish 3-D object reconstruction in a practical optical configuration. Comparison between reconstructed results and simulation is made to validate presented method. The feasibility of calculating method for a hologram is proven.