Border processing in digital holography by extension of the digital hologram and reduction of the higher spatial frequencies

Dubois, Frank; Monnom, Olivier; Yourassowsky, Catherine; Legros, Jean Claude

doi:10.1364/ao.41.002621

Cited by 42 publications

(17 citation statements)

References 12 publications

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“…As the vesicles are transparent objects, when they are focused, it is necessary to take benefit of the phase information, to locate them in the experimental volume. Digital holographic reconstruction coupled to specific algorithmic techniques for object detection (Dubois et al , 2002 permits to obtain the size, projected shape in the XY plane, 3D position, and an estimation of the mean velocity of each flowing vesicle.…”

Section: Digital Holographic Microscopementioning

confidence: 99%

Dynamics of Vesicle Suspensions in Shear Flow Between Walls

Podgorski

Callens

Minetti

et al. 2010

Microgravity Sci. Technol.

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International audienceThe behaviour of a vesicle suspension in a simple shear flow between plates (Couette flow) was investigated experimentally in parabolic flight and sounding rocket experiments by Digital Holographic Microscopy. The lift force which pushes deformable vesicles away from walls was quantitatively investigated and is found to be rather well described by a theoretical model by Olla (J Phys II (France) 7:1533, 1997). At longer shearing times, vesicles reach a steady distrib- ution about the center plane of the shear flow chamber, through a balance between the lift force and shear induced diffusion due to hydrodynamic interactions between vesicles. This steady distribution was inves- tigated in the BIOMICS experiment in the MASER 11 sounding rocket. The results allow an estimation of self-diffusion coefficients in vesicle suspensions and reveal possible segregation phenomena in polydisperse suspensions

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Section: Digital Holographic Microscopementioning

confidence: 99%

Dynamics of Vesicle Suspensions in Shear Flow Between Walls

Podgorski

Callens

Minetti

et al. 2010

Microgravity Sci. Technol.

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“…After two interferograms are recorded on the CCD, we carry out a signal processing by computer in order to eliminate high spatial frequency components due to the scattering noise from the test surface. This removal method is done by 3 × 3 median filtering process [16]. Fig.…”

Section: Experiments and Resultsmentioning

confidence: 99%

Measurement of a Mirror Surface Topography Using 2-frame Phase-shifting Digital Interferometry

Jeon

Gil

2009

Journal of the Optical Society of Korea

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We propose a digital holographic interference analysis method based on a 2-frame phase-shifting technique for measuring an optical mirror surface. The technique using 2-frame phase-shifting digital interferometry is more efficient than multi-frame phase-shifting techniques because the 2-frame method has the advantage of a reduced number of interferograms, and then takes less time to acquire the wanted topography information from interferograms. In this measurement system, 2-frame phaseshifting digital interferograms are acquired by moving the reference flat mirror surface, which is attached to a piezoelectric transducer, with phase step of 0 or π/2 in the reference beam path. The measurements are recorded on a CCD detector. The optical interferometry is designed on the basis of polarization characteristics of a polarizing beam splitter. Therefore the noise from outside turbulence can be decreased. The proposed 2-frame algorithm uses the relative phase difference of the neighbor pixels. The experiment has been carried out on an optical mirror which flatness is less than λ/4. The measurement of the optical mirror surface topography using 2-frame phaseshifting interferometry shows that the peak-to-peak value is calculated to be about 0.1779 μm, the root-mean-square value is about 0.034 μm. Thus, the proposed method is expected to be used in nondestructive testing of optical components.

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“…This section summarizes the different algorithms developed for the automatic data process. The whole process can be decomposed in the following steps [5][6][7] :…”

Section: Discussionmentioning

confidence: 99%

Dynamics of vesicle suspension in shear flow between walls by digital holographic microscopy with a spatially reduced coherent source

et al. 2012

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Digital Holographic Microscopy (DHM) is a powerful tool that strongly increases the field of investigation of classical microscopy. It allows to be used as phase contrast microscopy with the additional information of the z position over a whole experimental volume by acquiring a single frame. The use of a spatially reduced coherent source strongly reduces the coherent noise.Vesicles are close lipid membranes enclosing a sugar-water solution. Those biomimetic deformable objects are good mechanical models of living cells such as Red Blood Cells. We investigate the dynamics of a vesicle suspension in shear flow between walls (with a gap of about 200 µm). When vesicles are placed in a shear flow, they undergo a lift force that pushes them away from the wall until they reach the centre of the channel where the effects of both walls are compensated. On the other hand, hydrodynamical interactions between vesicles and segregation effects tend to push small vesicles away from the centre of the channel. The final distribution is thus a compromise between both effects that structures the distribution and has strong impact on rheology.DHM with reduced coherence and specific related algorithms (phase compensation, best focus plane determination, segmentation, …) provide a full description of each object in the experimental volume as a function of their size and shape. Results are provided and illustrate the quantification of the lift force and the hydrodynamical interactions (shear induced diffusion).

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Border processing in digital holography by extension of the digital hologram and reduction of the higher spatial frequencies

Cited by 42 publications

References 12 publications

Dynamics of Vesicle Suspensions in Shear Flow Between Walls

Dynamics of Vesicle Suspensions in Shear Flow Between Walls

Measurement of a Mirror Surface Topography Using 2-frame Phase-shifting Digital Interferometry

Dynamics of vesicle suspension in shear flow between walls by digital holographic microscopy with a spatially reduced coherent source

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