Computer Generated Holograms With A Multi-view-Projection Algorithm

Computer-generated holography(CGH)three-dimensional display is a display technology that records and reconstructs the amplitude and phase information of an object through simulating optical system on computer.This technology not only reduces the requirements of the device,but also simplifies the actual operation.So it has high flexibility and repeatability,making it be one of the most potential technologies in the naked eye 3D display technology.According to the basic theory of CGH,the spectral information of synthetic three-dimensional object is obtained by sampling the Fourier spectrum of multi-view projection image,and then encoding it to generate and reconstruct the CGH of three-dimensional object;Combined with the weighted sampling method,we establish the projection scanning model under the unified spectrum sampling.The simulation results show that this improved-algorithm improves the quality of hologram generated by multi-view projection algorithm.The specific work is as follows:(1)In this paper,briefly expound the development of 3D display technology at home and abroad,and then the theoretical and technical basis of CGH is introduced in detail.Firstly,the classification of CGH,the production and reconstruction of holograms,and the advantages of CGH are briefly described.And then the sampling,diffraction calculation and coding process of CGH are analyzed in detail.Finally,the point source method,the tomography method and the multi-view projection method of CGH are compared,which provides a theoretical basis for the improved algorithm based on multi-view projection method.(2)For the multi-view projection algorithm based on circular scanning method,computer improves the imaging quality of computational hologram reconstruction by multi-?-angle circular scanning method and weighted sampling algorithm.The projection image is obtained by multi-?-angle circular scanning,and the spectrum sampling information of the overlapping position of multi-projection image is determined according to the criterion of "small ? angle first,big weight second";Through weighted sampling of projection spectrum,computer adaptively selects a few grid points with good consistency like ideal sampling point spectrum information as actual sampling points in a single projection spectrum.The simulation results show that the improved algorithm can extract the spectral information of the projection image adequately and suppress the formation of noise effectively.And it can improve the visual quality of the computed hologram and thereconstructed image with fewer sampling points.(3)For the multi-view projection algorithm based on orthogonal scanning method,computer obtains the spectral sampling circle of the circular scan projection image of a specific angle from the orthogonal scanning projection image and determines the overlapping position of the analog sampling circular spectrum information according to the criterion of “small ? angle first”.And then computer selects the actual sampling point combined with weighted sampling algorithm.The simulation results show that the improved algorithm can not only improve the spectral efficiency of the projected image effectively,but also improve the visual quality of the reconstructed image significantly without increasing the number of projected images.