Higher-order statistical properties of speckle fields and their application to rough-surface interferometry

Vry, U.; Fercher, Adolf Friedrich

doi:10.1364/josaa.3.000988

Cited by 31 publications

(6 citation statements)

References 11 publications

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“…This is due to the speckle effect on rough surfaces, which depends on the laser wavelength as well as on the angle of the incident light. With increasing tilting angle ψ and wavelength difference Δλ the speckle pattern of both interference fringe systems becomes more dissimilar, which was already shown at rough surface speckle interferometry [9]. At the P-LDDS, the dissimilar speckle patterns result in Doppler-modulated light signals with different envelopes and phase jumps at different times.…”

mentioning

confidence: 71%

Distance measurement technique using tilted interference fringe systems and receiving optic matching

Günther¹,

Kuschmierz²,

Pfister³

et al. 2012

Opt. Lett.

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The precise measurement of the distance of fast laterally moving rough surfaces is important in several applications such as lathe monitoring. A nonincremental interferometer based on two tilted interference fringe systems and a precise phase-difference estimation has been realized for this task. However, due to the speckle effect, the two scattered light signals exhibit different phase jumps and random envelopes causing small correlation coefficients and high uncertainties of the phase difference as well as the distance. In this Letter we present for the first time a method to enhance the signal correlation coefficient significantly. The interference signals are generated by scattered light of a rough surface from two different directions. A matching of illumination and receiving optic is performed. By this novel method, distance measurements with an uncertainty down to 1.2 μm at about 10 m/s lateral moving velocity have been achieved. Together with the simultaneously measured lateral velocity, the shape of rotating objects can be precisely determined.

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mentioning

confidence: 71%

Distance measurement technique using tilted interference fringe systems and receiving optic matching

Günther¹,

Kuschmierz²,

Pfister³

et al. 2012

Opt. Lett.

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“…Synthetic wavelength holography. Our SWH approach draws inspiration from multi-wavelength interferometry on rough surfaces [40][41][42][43][44][45][46] : We exploit spectral correlations in scattered light at optical wavelengths λ 1 , λ 2 to assemble a hologram of the obscured objects at the SWL Λ ¼ λ 1 λ 2 jλ 1 À λ 2 j . The approach provides a combination of capabilities that is unmatched by competing NLoS approaches:…”

Section: Resultsmentioning

confidence: 99%

“…The artifacts are attributed to a loss in the spectral correlation of the scattered fields observed at λ 1 , λ 2 . The physical origins of this decorrelation are well documented in literature 39,[42][43][44][53][54][55][56][57][58][59][60][61] . The Supplementary Material includes a derivation for the specific case of looking around corners.…”

mentioning

confidence: 91%

“…This is because the light at the two wavelengths traverses nearly identical ray paths and experiences nearly identical path length fluctuations. Hence, the residual changes in phase |ϕ(λ 1 ) − ϕ(λ 2 )| encode the macroscopic structure of the obscured object 34,[40][41][42][43][44] . We exploit this fact to probe the scattering medium at two closely spaced wavelengths λ 1 and λ 2 , and record the emerging speckle fields E(λ 1 ) and E(λ 2 ), as illustrated in Fig.…”

mentioning

confidence: 99%

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Fast non-line-of-sight imaging with high-resolution and wide field of view using synthetic wavelength holography

Willomitzer

Rangarajan

et al. 2021

Nat Commun

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The presence of a scattering medium in the imaging path between an object and an observer is known to severely limit the visual acuity of the imaging system. We present an approach to circumvent the deleterious effects of scattering, by exploiting spectral correlations in scattered wavefronts. Our Synthetic Wavelength Holography (SWH) method is able to recover a holographic representation of hidden targets with sub-mm resolution over a nearly hemispheric angular field of view. The complete object field is recorded within 46 ms, by monitoring the scattered light return in a probe area smaller than 6 cm × 6 cm. This unique combination of attributes opens up a plethora of new Non-Line-of-Sight imaging applications ranging from medical imaging and forensics, to early-warning navigation systems and reconnaissance. Adapting the findings of this work to other wave phenomena will help unlock a wider gamut of applications beyond those envisioned in this paper.

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“…The object recorded at λ 1 is played back with λ 2 and superimposed with the waves from the real object illuminated at λ 2 . The interference pattern displays contour lines at a distance given by the "synthetic" wavelength [31][32][33][34]…”

Section: ) Holography Vs Rough Surface Interferometrymentioning

confidence: 99%

Reflections about holographic and non-holographic acquisition of surface topography

Häusler¹,

Willomitzer²

2021

Preprint

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Recording and (computational) processing of complex wave fields offers a vast realm of new optical methods. Also for optical 3D-metrology. We discuss fundamental similarities and differences of holographic surface topography measurement versus non holographic principles, such as triangulation, classical interferometry, rough surface interferometry and slope measuring methods. Key features are the physical origin of the ultimate precision limit and how the topographic information is encoded and decoded. We demonstrate that the question "is holography just interferometry?" has different answers, depending on how we exploit holograms or interferograms for metrology. The answers will help users to find out if their measurement results could be improved or if they already hit the ultimate limit of what physics allows.

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Higher-order statistical properties of speckle fields and their application to rough-surface interferometry

Cited by 31 publications

References 11 publications

Distance measurement technique using tilted interference fringe systems and receiving optic matching

Distance measurement technique using tilted interference fringe systems and receiving optic matching

Fast non-line-of-sight imaging with high-resolution and wide field of view using synthetic wavelength holography

Reflections about holographic and non-holographic acquisition of surface topography

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