Four dimensional phase unwrapping of dynamic objects in digital holography

Abstract

We present a new four-dimensional phase unwrapping approach for time-lapse quantitative phase microscopy, which allows reconstruction of optically thick objects that are optically thin in a certain temporal point and angular view. We thus use all four dimensions of the dynamic quantitative phase profile acquired, including the angular dimension and the temporal dimension, in addition to the x-y dimensions. We first demonstrate the capabilities of this algorithm on simulative data, enabling the quantification of the reconstruction quality relative to both the ground truth and existing unwrapping approaches. Then, we demonstrate the applicability of the proposed four-dimensional phase unwrapping algorithm by experimentally capturing a dual-angular dynamic off-axis hologram with simultaneous recording of two angular views, using multiplexing of two off-axis holograms into a single multiplexed hologram.

Decoupling of cell refractive index and thickness distribution under three-wavelength phase imaging

“…According to the method in this paper, the cytoplasmic RI n1 can be calculated according to formulas ( 9), (10), and (13). The RI n2 of the nucleus can be calculated according to formulas (11), (12), and (13). Eqs.…”

“…The direct thickness measurement method measures geometric thickness by different imaging methods, such as atomic force microscopy [4], confocal reflectance microscopy [5], and the combination of a confocal fluorescence microscopy and phase microscopy [6], but these methods increase the complexity of the combined system and may damage cells. Tomographic phase microscopy method (TPM) uses the phase [7][8][9][10][11] to image objects from different perspectives. After digitizing the phase map, it is possible to decouple two-dimensional information and obtain a three-dimensional distribution of the RI of the cells, but the method requires multiple measurements and extensive calculations for many angles.…”

Is multiplexed off-axis holography for quantitative phase imaging more spatial bandwidth-efficient than on-axis holography? [Invited]

“…In optical multiplexing [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], multiple sample and reference beam pairs with different 𝜃 𝑥 and 𝜃 𝑦 combinations are projected onto the digital camera simultaneously, each of which creating an off-axis hologram with a different interference fringe direction that positions one wavefront in the SFD without overlapping other terms. The simultaneous projection of all beams on the camera may create unwanted interference between nonmatching pairs.…”

“…Various basic architectures have been demonstrated for optical multiplexing. These include multiplexing two holograms by positioning two complex wavefronts in two orthogonal directions [11][12][13][14][15][16][17][18][19][20][21], which can be generalized to multiplexing three [22][23][24][25], four [26][27][28], five [29], or even six holograms [30], all without SFD overlap.…”

“…Tian et al multiplexed four low-resolution LED illuminations for Fourier Ptychography [28]. Finally, Dardikman et al multiplexed two angular views of the same scene over time to enable 4-D phase unwrapping [20], and Kostencka et al multiplexed two angular views for reducing the data acquisition time in tomographic phase microscopy [21].…”