Shaked Natan T, Katz Barak, Rosen Joseph
Department of Electrical and Computer Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel.
Appl Opt. 2009 Dec 1;48(34):H120-36. doi: 10.1364/AO.48.00H120.
Methods of generating multiple viewpoint projection holograms of three-dimensional (3-D) realistic objects illuminated by incoherent white light are reviewed in this paper. Using these methods, it is possible to obtain holograms with a simple digital camera, operating in regular light conditions. Thus, most disadvantages characterizing conventional digital holography, namely the need for a powerful, highly coherent laser and extreme stability of the optical system, are avoided. The proposed holographic processes are composed of two stages. In the first stage, regular intensity-based images of the 3-D scene are captured from multiple points of view by a simple digital camera. In the second stage, the acquired projections are digitally processed to yield the complex digital hologram of the 3-D scene, where no interference is involved in the process. For highly reflecting 3-D objects, the resulting hologram is equivalent to an optical hologram of the objects recorded from the central point of view. We first review various methods to acquire the multiple viewpoint projections. These include the use of a microlens array and a macrolens array, as well as digitally generated projections that are not acquired optically. Next, we show how to digitally process the acquired projections to Fourier, Fresnel, and image holograms. Additionally, to obtain certain advantages over the known types of holograms, the proposed hybrid optical-digital process can yield novel types of holograms such as the modified Fresnel hologram and the protected correlation hologram. The prospective goal of these methods is to facilitate the design of a simple and portable digital holographic camera that can be useful for a variety of practical applications, including 3-D video acquisition and various types of biomedical imaging. We review several of these applications to signify the advantages of multiple viewpoint projection holography.
本文综述了生成由非相干白光照明的三维（3-D）逼真物体的多视角投影全息图的方法。使用这些方法，可以用普通数码相机在常规光照条件下获得全息图。因此，避免了传统数字全息术的大多数缺点，即需要强大的、高相干性的激光器以及光学系统的极端稳定性。所提出的全息过程由两个阶段组成。在第一阶段，通过普通数码相机从多个视角捕获基于强度的3-D场景的常规图像。在第二阶段，对获取的投影进行数字处理，以生成3-D场景的复数字全息图，该过程不涉及干涉。对于高反射率的3-D物体，所得全息图相当于从中心点记录的物体的光学全息图。我们首先回顾获取多视角投影的各种方法。这些方法包括使用微透镜阵列和宏透镜阵列，以及非光学获取的数字生成投影。接下来，我们展示如何将获取的投影数字处理为傅里叶全息图、菲涅耳全息图和图像全息图。此外，为了获得优于已知类型全息图的某些优势，所提出的混合光学 - 数字过程可以产生新型全息图，如改进的菲涅耳全息图和受保护的相关全息图。这些方法的预期目标是促进设计一种简单便携的数字全息相机，可用于各种实际应用，包括3-D视频采集和各种生物医学成像。我们回顾其中一些应用，以表明多视角投影全息术的优势。
