Three-Dimensional Imaging Using Coded Aperture Correlation Holography (COACH)

Digital holography has long been known for its beneficial capabilities in optical imaging, especially as a three-dimensional and phase imaging enabler. In the modern era, when electro-optical and computational resources are almost endless, introducing coded masks for practical beam modulation is an important milestone in the field. This chapter surveys the evolution of correlation holography from the early stage of Fresnel incoherent systems to mature, general, coded aperture systems. By surveying various application-driven designs of coded mask-aided imaging systems, we highlight the significance of modularity in this ongoing research. The ability to adapt the presented methodology to solve current challenges, a capacity granted by the coded masks, is shown to impact the broader field of optical imaging. As a case study, we examine the combination of two coded correlation holographic modalities to address a well-known bottleneck in these depth-resolving imaging systems. Violation of the Lagrange invariant in the early versions is successfully maintained in the later, chaotic mask implementation to provide an uncompromised super-resolution technique. Hopefully, this and other implementations mentioned in a nutshell within this chapter provide concrete evidence that coded mask systems are a key player in the landscape of digital holography and essential for further development of the field.