Vibration analysis by speckle techniques in real time

Tiziani, Hans J.; Klenk, Jürgen

doi:10.1364/ao.20.001467

Cited by 31 publications

(8 citation statements)

References 6 publications

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“…Fringes obtained in this way, in the Fraunhofer plane, no longer follow a cosine-square law but the square of the Bessel function, of order zero and first kind [6,10]. From the minima of the Bessel function, the amplitude of oscillation can be found.…”

Section: Real-time Speckle Applications With Bso Crystalsmentioning

confidence: 91%

“…Real-time speckle photography was found to be very promising for analysis of deformation, tilt and displacement [5], or for time-average recording for vibration analysis [6]. The experimental layout is shown in figure 8.…”

Section: Real-time Speckle Applications With Bso Crystalsmentioning

confidence: 99%

“…The specific applications to be discussed in the paper are real-time interferometry for deformation and vibration analysis and contour-line holography as well as speckle applications. [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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Real-time Metrology with BSO Crystals

Tiziani

1982

Optica Acta: International Journal of Optics

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Abstract. Electro-optical crystals are used for real-time holography, optical data storage, optical information processing and more recently for speckle applications. Many ferro-electric materials were investigated, the Bi12 Si0 20 (BSO), a cubic, para-electric and electro-optic material was found to be very useful for real-time holographic interferometry and speckle applications. For the application of the BSO in real-time metrology, the crystals is usually biased with a transverse electric field in the 110 or 100 crystallographic direction. Illuminating the crystal with spatially structured information in the no direction as a result of a hologram or speckle pattern, a space charge field is built up, leading to a refractive index variation in the crystal. Double-exposure techniques and time average exposure will be presented for real-time deformation displacement and vibration analysis and for contour line holography using a two-wavelengths method.Young's fringes of double-exposed, or in the time-average recorded speckle patterns will be attractive for real-time deformation displacement and vibration analysis.

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Section: Real-time Speckle Applications With Bso Crystalsmentioning

confidence: 91%

Section: Real-time Speckle Applications With Bso Crystalsmentioning

confidence: 99%

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Real-time Metrology with BSO Crystals

Tiziani

1982

Optica Acta: International Journal of Optics

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“…Different photo refractive materials [1] such as bismuth silicium oxide Bi l2 Si0 20 (BSO), bismuth germanium oxide Bil2Ge020 (BGO), bismuth titane oxide Bil2 Ti0 20 (BTO), and barium titanate BaTi0 3 can be used as storage material in holography [2] and speckle techniques [3]. In this report however, BSO is applied as a transparent photoconductor layer in an optically addressed spatial light modulator (SLM) based on liquid crystals (LCs) [4].…”

Section: Introductionmentioning

confidence: 99%

Spatial Light Modulator Used for the Fourier Transformation of Video Images

Schönleber

Tiziani

1993

Journal of Modern Optics

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Abstract. Coherent-optical Fourier transformation of video images can be very powerful; a set-up will be described. The modulation of the coherent beam occurs in a spatial light modulator where the liquid crystal display image of the object is projected onto an optically addressed spatial light modulator that uses bismuth silicium oxide for photoconduction and a twisted nematic liquid crystal as a birefringent layer. Edge enhancing of the image can occur; in addition, it appears that the Fourier spectrum of an edge is asymmetric due to local phase variations. The set-up was applied to recognize objects at different positions. A chargecoupled device matrix camera detects the Fourier plane, in the personal computer the pixels are summed up to ring-wedge-segments and processed for pattern recognition.

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“…Displacements, tilts, and deformations of the input diffuser produce displacements and structural changes in the speckle patterns, which can be analyzed on the basis of the double-exposure imaged speckles, before and after deformation. In previous papers, the use of a thick photorefractive crystal as a speckle recording medium was proposed [13][14][15][16]. In [17][18][19], the storage in a sillenite crystal of low frequency modulated speckle patterns is analyzed.…”

mentioning

confidence: 99%

Experimental study of volume speckle in four-wave mixing arrangement

Salazar

Tebaldi

Bolognini

2003

Optics Communications

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We study a high frequency modulated speckle pattern in a four wave mixing arrangement. The three-dimensional nature o f the speckles is considered in the phase conjugate reflectivity evaluation which implies to analyze its depen dence on the average speckle size. Also, the reflectivity is analyzed in terms of the external applied field, the probe beam ratio, and the pupil aperture diameter o f the imaging system that generates the subjective speckle beam. waves through scattering media such as the at mosphere.The first experience of phase conjugation in a photorefractive material was done by Huignard et al. [4]. Applications of phase conjugation to nondestructive testing, image processing, and imaging through phase disturbing media have been already demonstrated [5 9]. In [10] a real time double exposure holographic interferometric method of testing phase object by using degenerate four-wave mixing DFWM with photorefractive Bii2GeC>20 (BGO) crystals has been reported.As it is well known, when a diffusing surface is illuminated by coherent light, speckles appear in front of the surface. The speckle patterns have important applications in the field of metrology

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Vibration analysis by speckle techniques in real time

Cited by 31 publications

References 6 publications

Real-time Metrology with BSO Crystals

Real-time Metrology with BSO Crystals

Spatial Light Modulator Used for the Fourier Transformation of Video Images

Experimental study of volume speckle in four-wave mixing arrangement

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