This work was supported by the Gordon and Betty Moore Foundation (GBMF) grant number 4038 and the National Science Foundation Award #1828793. Portions of this work were carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Frontiers in Physics
Digital holographic microscopy -- Algorithms, Holography -- Mathematical aspects, Image processing, Protozoa
Multiwavelength digital holographic microscopy (DHM) has been used to improve phase reconstructions of digital holograms by reducing 2p phase ambiguities. However, most samples used as test images have been solid or adhered to a surface, making it easy to determine focal planes and correct for chromatic aberration. In this study we apply 3-wavelength off-axis DHM to swimming protozoa containing distinct spectral features such as chlorophyll and carotenoids. We reconstruct the holograms into amplitude and phase images using the angular spectrum method. Methods for noise subtraction, chromatic aberration correction, and image registration are presented for both amplitude and phase. Approaches to phase unwrapping are evaluated and compared to expected results from simulated holograms. The algorithms used are implemented in plug-ins using the open source Fiji platform and are available for use, significantly expanding the open-source software available for DHM.
Cohoe, D., Hanczarek, I., Wallace, J. K., & Nadeau, J. (2019). Multiwavelength digital holographic imaging and phase unwrapping of protozoa using custom Fiji plug-ins. Frontiers in Physics, 7, 94.