Results 211 to 220 of about 20,096 (267)
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Spectral Speckle Interferometry
Astrophysics and Space Science, 1989A method of obtaining an objective prism spectrum of a stellar object with diffraction-limited spatial resolution is described.
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SPIE Proceedings, 1985
The atmosphere of the earth restricts the resolution of conventional astrophotography to about 1". We will discuss various high-resolution speckle methods which can overcome image degradation caused by the atmosphere and telescope aberrations. All methods yield diffraction-limited resolution, for example 0.03" for a 3.6m telescope. We will show various
G. Weigelt +5 more
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The atmosphere of the earth restricts the resolution of conventional astrophotography to about 1". We will discuss various high-resolution speckle methods which can overcome image degradation caused by the atmosphere and telescope aberrations. All methods yield diffraction-limited resolution, for example 0.03" for a 3.6m telescope. We will show various
G. Weigelt +5 more
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Phase-shifting speckle interferometry
Applied Optics, 1985Speckle patterns have high frequency phase data, which make it difficult to find the absolute phase of a single speckle pattern; however, the phase of the difference between two correlated speckle patterns can be determined. This is done by applying phase-shifting techniques to speckle interferometry, which will quantitatively determine the phase of ...
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Materials Testing, 1996
With the electronic laser speckle interferometry (ESPI) it is possible to make deformation and strain fields visible. An easy to use sensor is presented. For demonstration the inhomogeneous deformation behaviour of laser-welded aluminium sheet is shown. At lower load the deformation is homogeneous, at higher load there is a deformation concentration in
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With the electronic laser speckle interferometry (ESPI) it is possible to make deformation and strain fields visible. An easy to use sensor is presented. For demonstration the inhomogeneous deformation behaviour of laser-welded aluminium sheet is shown. At lower load the deformation is homogeneous, at higher load there is a deformation concentration in
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Electronic speckle interferometry
ICALEO '88: Proceedings of the Optical Sensing and Measurement Conference, 1988Electronic Speckle Pattern Interferometry (ESPI) is becoming a very common test and measurement tool among industrial users. In its present form it rivals any current techniques for speed and ease of use. With improvements in image quality it has the potential to become the definitive tool for non-destructive testing.
Brad Sharp, Aaron Gara
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Speckle Interferometry And Differential Speckle Interferometry Using Cross-Spectrum Techniques
Optical Engineering, 1986A cross-spectrum analysis technique that makes it possible to compute an unbiased estimate of the speckle pattern Wiener spectrum has been developed at the University of Nice. Using a one-dimensional interferometer, the technique has given results on several subjects such as the study of atmospheric modulation transfer function, including anisotropy ...
Claude Aime +4 more
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Electronic Speckle Pattern Interferometry
Topical Meeting on Holography, 1986Holographic workstations are now enabling the advantages of Holographic Interferometry (HI) to be taken outside research laboratories and placed alongside manufacturing equipment. Most rigidization problems have been overcome but two handicaps still limit its widespread application.
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Digital speckle-pattern shearing interferometry
Applied Optics, 1980An application of digital image processing techniques to speckle-shearing interferometry is described. A present system consists of an image-shearing camera using a Fresnel biprism of small angles and a digital TV-image processing facility. This interferometer makes it easy to measure in quasi-real-time spatial derivatives of surface displacement and ...
S, Nakadate, T, Yatagai, H, Saito
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Optics & Laser Technology, 1984
Abstract A number of speckle shear methods and their applications to ndt are discussed. Experiments using multiple apertures with custom-made optical elements have shown that in-plane displacement, slope and curvature patterns can be obtained by filtering through appropriate haloes.
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Abstract A number of speckle shear methods and their applications to ndt are discussed. Experiments using multiple apertures with custom-made optical elements have shown that in-plane displacement, slope and curvature patterns can be obtained by filtering through appropriate haloes.
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Heterodyne temporal speckle-pattern interferometry
Applied Optics, 2000In temporal speckle-pattern interferometry deformation information is extracted by a Fourier transform technique from the speckle pattern that is recorded over a period of time as the object is deformed. A limitation of the experimental arrangements reported to date is that the direction of the deformation cannot be determined. We propose removing this
P, Haible, M P, Kothiyal, H J, Tiziani
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