三维场景相息图的白光再现研究

讨论了相息图白光再现的可行性,得到采用在相息图和观察者之间加入狭缝的方法可实现相息图的白光再现的结论.提出了一种通过对彩虹全息图进行复数滤波来制作相息图的方法.根据彩虹全息图中物光的频谱宽度设计有限脉冲响应数字滤波器.对该滤波器进行移频,得到与通带位置物光的频谱位置一致的复系数带通滤波器.对全息图进行空域滤波,去除共轭像和零级,求出调制后物光的位相分布,制作场景相息图.实验观察到了经过此方法制作的相息图在白光下的再现像,表明本文的理论分析正确,所提出的方法可行.

Study on Reconstruction of the Kinoform with White-light Illumination

The practicability of reconstructing the kinoform with white-light is discussed. It is drawn that the kinoform could be reconstructed with white-light, if a slit was placed between the kinoform and observer(we call this kind of kinoform as rainbow kinoform). And then, a method for making rainbow kinoform is proposed. Firstly, the computer-generated rainbow hologram is calculated. Secondly, a finite impulse response(FIR) low-pass filter with real coefficients is designed according to the band-width of the object. Thirdly, the FIR band-pass filter with complex coefficient is gained by moving the spectrum of low-pass filter to the position where the spectrum of object is located.Fourthly, the zero-order and conjugate image is eliminated by filtering the rainbow hologram with designed filter in spatial domain. Finally, the kinoform of 3D scenes is made by extracting the object phase distribution of the filtered hologram. In our exprements, the clear reconstructed image of rainbow kinoform was observed under white-light illumination. It is proved that the proposed approach is feasible.