数字全息中的一些基本问题分析

Analysis of Some Fundamental Issue about Digital Hologram

利用全息理论、傅里叶频谱分析和采样定理 ,在模拟和数字全息光栅实验基础上 ,分析了数字全息记录和再现中的一些基本问题。结果表明 :在物体和CCD尺寸确定的情况下 ,记录光路结构参量只取决于对图像采样的要求及CCD的像素尺寸 ,只要物体到CCD的距离满足采样要求 ,数字全息图再现光场的三个部分就可以分离 ;用准直平行光作为记录参考光和模拟再现光 ,可以得到与物体大小和形状完全一致的再现像 ;采样条件对再现像的影响大于分离条件 ,减小参物光的夹角记录适当过采样的数字全息图 ,有利于提高再现像的质量 ;另外 ,在获得高质量再现像方面 ,根据物体的具体特征 ,尽可能记录高质量的数字全息图 。

By use of holographic theory,Fourier transform frequency spectrum analysis and sampling theorem, this analysis of some fundamental issues about digital hologram by computer simulation and the experiment of digital grating is given. The results show: if the size of object and CCD is fixed, the structure parameter of the recording system only correlate with sampling requirement and the size of CCD pixels, and so as the distance between object and CCD accord with the sampling requirement, the three parts of digital reconstructed image can be separated. If the reference light and reconstructed light are both parallel light, the size and profile of the reconstructed image is equal to that of the object. Meanwhile the influence of sampling requirement is more than the separation condition, by decreasing the angle between reference light and object light, and recording certain over-sampling digital hologram, the quality of reconstructed image can be improved. Finally, in order to obtain high quality digital reconstructed image, it is also important to record high quality hologram according to object optical character.