Detection of movement with laser speckle patterns: statistical properties

Schnell, U.; Piot, J.; Dändliker, R.

doi:10.1364/josaa.15.000207

Cited by 24 publications

(20 citation statements)

References 10 publications

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“…In case optical spatial filtering velocimetry is applied to a one-dimensional, in-plane translation of an intensity distribution relative to the filter [5], the intensity transmittance tp for the optimum spatial filter will have a one-dimensional repetitive structure. Therefore, the intensity transmittance obeys that tp tp Λ where the direction of Λ defines the direction of the displacement or velocity component to be measured, and jΛj defines the structural period of the intensity transmittance.…”

Section: B Spatial Filtermentioning

confidence: 99%

“…The techniques of SP and DSP have also been combined with optical spatial filtering velocimetry (OSFV) [4] in order to carry out single-point measurements of moving particles or rigid objects [5]. Such techniques can be integrated conveniently into a compact optical sensor [6], providing nearly realtime measurements of one or two components of an object in-plane motion [7].…”

Section: Introductionmentioning

confidence: 99%

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Spatial filtering velocimetry of objective speckles for measuring out-of-plane motion

2012

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This paper analyzes the dynamics of objective laser speckles as the distance between the object and the observation plane continuously changes. With the purpose of applying optical spatial filtering velocimetry to the speckle dynamics, in order to measure out-of-plane motion in real time, a rotational symmetric spatial filter is designed. The spatial filter converts the speckle dynamics into a photocurrent with a quasi-sinusoidal response to the out-of-plane motion. The spatial filter is here emulated with a CCD camera, and is tested on speckles arising from a real application. The analysis discusses the selectivity of the spatial filter, the nonlinear response between speckle motion and observation distance, and the influence of the distance-dependent speckle size. Experiments with the emulated filters illustrate performance and potential applications of the technology.

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Section: B Spatial Filtermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spatial filtering velocimetry of objective speckles for measuring out-of-plane motion

2012

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“…For the transmitter with a DOE the trend is similar though we measure that the corresponding signal power is proportional to L -2. 9 .…”

Section: Gain In Signal Powermentioning

confidence: 99%

“…Arrays of photodetectors or slit apertures enable spatial-filtering velocimetry [1,2, 5,6], where phase information of a filter-specific spatial-frequency component contained in the intensity distribution of speckle patterns is extracted to provide the velocity information. Particularly, differential-detection arrangements with phase-quadrature detection, based on transmission-grating [7], lenticular arrays [8] or detector-comb arrays [9], can provide high-performance velocity measurements based on simple signal processing algorithms such as zero-crossing detection, and thus facilitate real-time processing.…”

Section: Introductionmentioning

confidence: 99%