Speckle decorrelation influence on measurements quality in vortex metrology

Ángel-Toro, Luciano; Sierra-Sosa, Daniel; Tebaldi, Myrian; Bolognini, Néstor

doi:10.1016/j.optcom.2012.07.021

Cited by 7 publications

(6 citation statements)

References 12 publications

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“…In a previous work [14], we presented experimental evidence to support the idea that under the restrictions imposed by the decorrelation of actual speckles, the reliability of results in general diminishes. In a previous work [14], we presented experimental evidence to support the idea that under the restrictions imposed by the decorrelation of actual speckles, the reliability of results in general diminishes.…”

Section: A Setups For Recording and Calibration Proceduresmentioning

confidence: 74%

Vortex metrology using Fourier analysis techniques: vortex networks correlation fringes

et al. 2012

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In this work, we introduce an alternative method of analysis in vortex metrology based on the application of the Fourier optics techniques. The first part of the procedure is conducted as is usual in vortex metrology for uniform in-plane displacement determination. On the basis of two recorded intensity speckled distributions, corresponding to two states of a diffuser coherently illuminated, we numerically generate an analytical signal from each recorded intensity pattern by using a version of the Riesz integral transform. Then, from each analytical signal, a two-dimensional pseudophase map is generated in which the vortices are located and characterized in terms of their topological charges and their core's structural properties. The second part of the procedure allows obtaining Young's interference fringes when Fourier transforming the light passing through a diffracting mask with multiple apertures at the locations of the homologous vortices. In fact, we use the Fourier transform as a mathematical operation to compute the far-field diffraction intensity pattern corresponding to the multiaperture set. Each aperture from the set is associated with a rectangular hole that coincides both in shape and size with a pixel from recorded images. We show that the fringe analysis can be conducted as in speckle photography in an extended range of displacement measurements. Effects related with speckled decorrelation are also considered. Our experimental results agree with those of speckle photography in the range in which both techniques are applicable.

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Section: A Setups For Recording and Calibration Proceduresmentioning

confidence: 74%

Vortex metrology using Fourier analysis techniques: vortex networks correlation fringes

et al. 2012

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“…Then, the object displacement in the hologram can be estimated from the phase singularity coordinate change (∆x, ∆y) along with the video. Notice that the phase singularities with large differences in their core structures failed to find their homologous and it must be eliminated [27].…”

Section: Vortex Tracking Techniquementioning

confidence: 99%

Vortex technique to track 3D object displacement in CGH

Amado¹,

Velez-Zea²,

Tebaldi³

2022

J. Opt.

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In this work, we introduce and test a technique to track the movement of objects from computer-generated holographic videos, without the need for reconstruction. To achieve this, we first generated holographic videos of moving 3D objects using a random phase layer-based approach. Then, we analyzed the hologram phase to determine the locations of the optical vortices. We used the core properties of each vortex to track its movement over all the frames of the video, and then establish a relationship between the object and the vortex movement. We also tested the vortex tracking over a pseudo-phase obtained by performing the Laguerre-Gauss transform of the hologram, which enables more precise control over the number of optical vortices that can be tracked. Our proposal was tested with holographic videos generated with one and two objects, using two different hologram generation approaches.

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“…The process is conducted by matching the core structure properties from the singularities related with a given object with those singularities found in a new scene. The phase singularities have in theory arbitrary location but due the experimental conditions its localization has some resolution and noise constrains, these restrictions where studied and presented in our previous work [13].…”

Section: Edge Enhancement and Tracking Procedures Descriptionmentioning

confidence: 99%