数字再现三维物体菲涅耳计算全息的研究

The Study of Numerical Reconstruction of Fresnel CGH of a 3-D Object

提出了一种用计算机产生和再现三维物体离轴菲涅尔 (Fresnel)全息图的数字方法。采用 Born近似法则建立了理想三维物体模型 ;利用博奇 (Burch)编码方法制作了此三维物体的计算全息图。通过卷积和快速傅立叶变换 (FFT)的方法计算衍射积分 ,以数字聚焦的方法进行再现。通过改变再现距离 ,获得了三维物体各截面的再现像。直接利用数字滤波技术消除了虚像和零级像 ,得到了清晰的实像。

A numerical method for producing and reconstructing Fresnel off line computer generated hologram(CGH) of a 3 D object is described in this paper.Based on the Born approximation,an ideal 3 D object model is builded.A CGH of the 3 D object is generated through the method of Burch coding.Using convolution and fast Fourier transform(FFT) algorithm to calculate diffraction integral,the CGH is reconstructed by digital focus method.The variety of layers of the 3 D object is reconstructed through using different distances between reconstructed image and CGH.By using digital filter method,twin images and zero order diffraction images are eliminated and clear real images are obtained.The 3 D objects CGH is presented in this paper,together with the results of numerical reconstruction of different sections.