利用压缩传感理论中的两步迭代收缩重建算法, 开展单幅同轴全息图重建实验研究, 实现单幅同轴全息图共轭重建像的消除并克服数字全息技术在轴向聚焦平面识别能力的不足。以数字图像和标准分辨率板为记录物体, 比较分析了基于两步迭代收缩算法和菲涅尔近似衍射重建算法的重建质量; 以两根裸光纤为实验样本, 分析了两步迭代收缩重建算法对记录物体轴向不同焦平面的识别能力。实验结果表明两步迭代收缩重建算法可得到清晰度高于68.73%的重建信息, 同时对直径为125 μm的两根光纤在9 mm的轴向间距条件下, 显示出了比全息菲涅尔近似算法更好的聚焦平面识别能力。这一轴向聚焦识别能力有助于数字全息技术应用于功能材料梯度参数或功能涂层光学器件涂层厚度检测。

Two-step iterative shrinkage / Threshold (TwIST) of compressive sensing theory is introduced. Experimental works on reconstruction of single in-line hologram are developed. The goal is to eliminate the reconstructed conjugate information of single in-line hologram and overcome the shortage of digital holography on identifying the axial focal plane. Simulation analysis and experiment works are developed. First, a digital image and the standard resolution target are used as the samples for hologram, the quality of the reconstructed image based on TwIST and Fresnel approximation algorithm is estimated respectively. Then two bare fibers (diameter of 125 μm) are selected as the test samples, identification capability of focal plane by TwIST is analyzed. The simulation and experimental results show that two-step iterative shrinkage algorithm can not only reconstruct the original information more than 68.73%, but also has a very good ability to identify the axial focal plane. These traits can help digital holography to detect some important parameters of functionally graded materials or the coating thickness of the optical functional coating devices.