Kumar Manoj, Vijayakumar A, Rosen Joseph, Matoba Osamu
Appl Opt. 2020 Aug 20;59(24):7321-7329. doi: 10.1364/AO.399088.
Lensless, interferenceless coded aperture correlation holography (LI-COACH) is an incoherent computational optical technique for three-dimensional (3D) imaging. In direct imaging, the image of the object is generated by a lens, whereas the LI-COACH is an indirect imaging technique that consists of two steps: one-time point spread hologram (PSH) training and then many times imaging of multiple-point objects. In the one-time training step, a point object moves in the object space along the optical axis. Light emitted from the point is modulated by a quasi-random phase mask, and the PSH library is recorded. In the imaging step, an object is mounted within the axial boundaries of the PSH library, and the object holograms are recorded using the same quasi-random phase masks. The 3D image of the object is reconstructed by the cross correlation of the object holograms with the PSH library. In this study, the entire PSH library is digitally synthesized from a single PSH, recorded at one plane only. The recorded PSH is scaled by magnification factors corresponding to the various axial planes. The reconstruction results from the synthetic PSH library are comparable with those from the recorded PSH library. The proposed approach can reduce the time of the training step in LI-COACH.
无透镜、无干涉编码孔径相关全息术（LI-COACH）是一种用于三维（3D）成像的非相干计算光学技术。在直接成像中，物体的图像由透镜生成，而LI-COACH是一种间接成像技术，包括两个步骤：一次性点扩散全息图（PSH）训练，然后对多点物体进行多次成像。在一次性训练步骤中，一个点物体在物空间中沿光轴移动。从该点发出的光由准随机相位掩模调制，并记录PSH库。在成像步骤中，将一个物体放置在PSH库的轴向边界内，并使用相同的准随机相位掩模记录物体全息图。通过物体全息图与PSH库的互相关来重建物体的3D图像。在本研究中，整个PSH库由仅在一个平面上记录的单个PSH数字合成。记录的PSH通过对应于各个轴向平面的放大因子进行缩放。合成PSH库的重建结果与记录的PSH库的重建结果相当。所提出的方法可以减少LI-COACH中训练步骤的时间。
