Phase Unwrapping Problems in Digital Holographic Microscopy of Biological Cells - Biomedical Optical Phase Microscopy and Nanoscopy - page 147

using the single wavelength phase imaging. In such a case, two wavelengths together allow
us to increase the maximum height of the features that can be unambiguously imaged.
The wave front curvature, which may be presented in the holographic image, needs to be
removed as well. The methods of curvature correction and background removal, presented
here, are simple and effective enough to easily implement the experiment without the
microscope objectives in the reference arms of the holographic interferometer. This greatly
simplifies the optical setup and makes it much easier to do the optical adjustments of the
apparatus. Simultaneous dual-wavelength setup utilized together with the angular spectrum
algorithm provides a way to acquire single frame images in real time, which can be used to
study cell migration, dynamic cellular volume change, etc. By extending unambiguous
optical phase imaging methods to objects of different heights, linear regression
dual-wavelength unwrapping method makes phase imaging much more practical, which
allow 3D measurements of a wide variety of biological systems and microstructures.
References
[1] D.C. Ghiglia, M.D. Pritt, Two-Dimensional Phase Unwrapping: Theory, Algorithms, and Software, John
Wiley & Sons, New York, NY, USA, 1998.
[2] A. Khmaladze, A. Restrepo-Mart ´ nez, M.K. Kim, R. Casta˜eda, A. Bland ´ n, Simultaneous dual-
wavelength reflection digital holography applied to the study of the porous coal samples, Appl. Opt. 47
(2008) 3203.
[3] A. Khmaladze, M.K. Kim, C.-M. Lo, Phase imaging of cells by simultaneous dual-wavelength reflection
digital holography, Opt. Express 16 (2008) 10900.
[4] M. Born, E. Wolfe, Principles of Optics, Pergamon, Oxford/London/Edinburgh/New York/Paris/Frankfurt,
1964.
[5] P. Ferraro, S. De Nicola, A. Finizio, G. Coppola, S. Grilli, C. Magro, et al., Compensation of the inherent
wave front curvature in digital holographic coherent microscopy for quantitative phase-contrast imaging,
Appl. Opt. 42 (2003) 1938.
[6] A. Khmaladze, R.L. Matz, J. Jasensky, E. Seeley, M.M. Banaszak Holl, Z. Chen, Dual-wavelength digital
holographic imaging with phase background subtraction, Opt. Eng. 51 (2012) 055801.
[7] C.A. Lieber, A. Mahadevan-Jansen, Automated method for subtraction of fluorescence from biological
Raman spectra, Appl. Spectrosc. 57 (2003) 1363.
[8] A. Khmaladze, T. Epstein, Z. Chen, Phase unwrapping by varying the reconstruction distance in digital
holographic microscopy, Opt. Lett. 35 (2010) 1040.
[9] A. Khmaladze, R.L. Matz, C. Zhang, T. Wang, M.M. Ting, M.M. Banaszak Holl, et al., Dual-wavelength
linear regression phase unwrapping in three-dimensional microscopic images of cancer cells, Opt. Lett. 36
(2011) 912.
[10] J. Gass, A. Dakoff, M.K. Kim, Phase imaging without 2 π -ambiguity by multiple-wavelength digital
holography, Opt. Lett. 28 (2003) 1141.
[11] H. Hendargo, M. Zhao, N. Shepherd, J. Izatt, Synthetic wavelength based phase unwrapping in spectral
domain optical coherence tomography, Opt. Express 17 (2009) 5039.
[12] U. Schnars, W. J¨ptner, Digital Holography: Digital Hologram Recording, Numerical Reconstruction, and
Related Techniques, Springer, Berlin/Heidelberg/New York, 2004.