处理双曝光数字全息的一种新方法

New method for processing double-exposed digital holography

在分析传统双曝光全息术和常用数字全息干涉术不足的基础上,利用数字全息术在全息记录与数字处理方面的灵活性,提出了一种处理双曝光数字全息记录结果的新方法——差值数字全息法。该方法首先将记录物体变形前后物光波与参考光波干涉场的2个数字全息相减,形成差值数字全息;然后对差值数字全息直接进行模拟衍射再现,就可以得到物体变形前后2个物光波的高质量干涉条纹。与通常的双曝光数字全息干涉技术及叠加数字全息法相比较,差值数字全息法的优点在于,既不需要事先专门消除数字全息中的零级强度项,只需要一次再现过程,并且所得干涉条纹的质量较高。在给出处理双曝光数字全息干涉技术记录结果的叠加数字全息法和差值数字全息法原理之后,通过实验及对实验结果的对比证明了差值数字全息法的可行性与优越性。

Analysing on the disadvantages of double-exposure holography, and using the flexibility of hologram recording and processing of digital hologrpahy, the difference digital hologram method （DDHM） for processing digital holograms of double-exposed digital holography（DEDH） was proposed. In the DDHM, the two digital holograms of object and deformed object are recorded, respectively, then subtraction of the two digital holograms is made and the difference digital hologram （DDH）is obtained. Finally the good quality interference fringes of optical waves of object and deformed object is got by virtually reconstructing the DDH. Comparing with DEDH and superposition digital hologram method（ SDHM）, the advantages of DDHM are, elimination of zero-order intensities of digital holograms is unnecessary, only the reconstuction of DDH is needed, and the quality of interference fringe is better. The principles of SDHM and DDHM for processing the digital holograms of DEDH were gived. The feasibility and superiority of DDHM were verified by experiments.