Complex-wave retrieval from a single off-axis hologram

Liebling, Michael; Blu, Thierry; Unser, Michaël

doi:10.1364/josaa.21.000367

Cited by 205 publications

(109 citation statements)

References 48 publications

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“…Optic convention is used here: high values (2p) are in white, whereas lower values (0) are in black. Most algorithms used for retrieving phase from an image or a series of images use one of the following methods: phase-shifting, Fourier transform (Takeda et al 1982), local wave retrieval (Liebling et al, 2004), or wavelets. The first three methods are outlined in Sects.…”

Section: Phase Mappingmentioning

confidence: 99%

Tracking the free surface of time-dependent flows: image processing for the dam-break problem

Cochard

Ancey

2007

Exp Fluids

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The dam-break problem (i.e., the sudden release of a given volume of fluid down a slope) has attracted a great deal of attention from mechanicians and physicists over the past few years, with particular interest devoted to the free-surface profile and the spreading rate. Experimentally, impediments to accurate measurements of the free-surface evolution are numerous because of the significant variations in its curvature and velocity. To accurately measure the surge's free-surface variations with time, we have developed a new imaging system, consisting of a digital camera coupled with a synchronized micromirror projector. The object's surface is imaged into a camera and patterns are projected onto the surface under an angle of incidence that differs from the imaging direction. From the deformed pattern recorded by the camera, the phase can be extracted and, by using unwrapping algorithms, the height can be computed and the free surface reconstructed. We were able to measure the free surface of the flow to within 1 mm over a surface of 1.8 · 1.1 m 2 . Although the techniques used in our system are not new when taken individually, the system in its entirety is innovative and more efficient than most methods used to-date in practical applications.

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Section: Phase Mappingmentioning

confidence: 99%

Tracking the free surface of time-dependent flows: image processing for the dam-break problem

Cochard

Ancey

2007

Exp Fluids

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“…A more general method that works for curved reference waves as well as plane waves was introduced in Ref. 128. Reference 104 describes a few different phase-shifting methods.…”

Section: Phase-shifting Digital Holographymentioning

confidence: 99%

Principles and techniques of digital holographic microscopy

2010

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Abstract. Digital holography is an emerging field of new paradigm in general imaging applications. We present a review of a subset of the research and development activities in digital holography, with emphasis on microscopy techniques and applications. First, the basic results from the general theory of holography, based on the scalar diffraction theory, are summarized, and a general description of the digital holographic microscopy process is given, including quantitative phase microscopy. Several numerical diffraction methods are described and compared, and a number of representative configurations used in digital holography are described, including off-axis Fresnel, Fourier, image plane, in-line, Gabor, and phase-shifting digital holographies. Then we survey numerical techniques that give rise to unique capabilities of digital holography, including suppression of dc and twin image terms, pixel resolution control, optical phase unwrapping, aberration compensation, and others. A survey is also given of representative application areas, including biomedical microscopy, particle field holography, micrometrology, and holographic tomography, as well as some of the special techniques, such as holography of total internal reflection, optical scanning holography, digital interference holography, and heterodyne holography. The review is intended for students and new researchers interested in developing new techniques and exploring new applications of digital holography. C 2010 Society of Photo-Optical Instrumentation Engineers.

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“…For applications requiring real-time or dynamic measurements, a different projection scheme was proposed: unwrapping using local wave algorithm (Liebling et al, 2004) from a single image (Cochard and Ancey, 2008).…”

Section: Phase Unwrappingmentioning

confidence: 99%

Optical method for measuring bed topography and flow depth in an experimental flume

et al. 2011

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Abstract. We describe an optical method known as moiré for acquiring quasi-simultaneous measurements of bed topography and flow depth in laboratory experiments. The moiré method is based on projecting a fringe pattern (grating) on the bed and analyzing the deformation of the pattern caused by the topography with respect to a reference plane. The height of the object is encoded in the phase of the pattern and can be retrieved either through Fourier transform or phase shifting algorithms. The methodology enables image-based non-contact measurements over a continuous surface at very high spatial and temporal resolutions. We use a commercial software package of a moiré method called Light3D to map bed topography and flow depth in an experimental braided channel and demonstrate how the method can be used to characterize a full range of statistics not previously possible.

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Complex-wave retrieval from a single off-axis hologram

Cited by 205 publications

References 48 publications

Tracking the free surface of time-dependent flows: image processing for the dam-break problem

Tracking the free surface of time-dependent flows: image processing for the dam-break problem

Principles and techniques of digital holographic microscopy

Optical method for measuring bed topography and flow depth in an experimental flume

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