Topic
Speckle imaging
About: Speckle imaging is a research topic. Over the lifetime, 3730 publications have been published within this topic receiving 62354 citations.
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TL;DR: A double-pulse electronic-speckle-interferometry system that uses three directions of illumination and one direction of observation to record at the same time all the information necessary for the reconstruction of the three-dimensional deformation vector.
Abstract: We describe a double-pulse electronic-speckle-interferometry system. Two separate speckle patterns of an object being tested are recorded within a few microseconds with a CCD camera. Their two images are stored in a frame grabber. The fringes obtained from subtraction are quantitatively analyzed by the spatial-carrier phase-shift method. Using three directions of illumination and one direction of observation, one can record at the same time all the information necessary for the reconstruction of the three-dimensional deformation vector. Applications of this system for measuring the rotating objects are discussed for the case for which a derotator needs to be used. Experimental results are presented.
97 citations
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TL;DR: The use of digital image processing techniques for electronic speckle pattern interferometry is discussed and some experimental verifications are presented in the cases of surface displacement and vibration amplitude measurements.
Abstract: The use of digital image processing techniques for electronic speckle pattern interferometry is discussed. A digital TV-image processing system with a large frame memory allows us to perform precise and flexible operations such as subtraction, summation, and level slicing. Digital image processing techniques make it easy compared with analog techniques to generate high contrast fringes. Some experimental verifications are presented in the cases of surface displacement and vibration amplitude measurements.
97 citations
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TL;DR: Experimental results show that the speckle contrast factor can be reduced down to 5% within the integration time of the detector.
Abstract: We utilize spatial and angular diversity to achieve speckle reduction in laser illumination. Both free-space and imaging geometry configurations are considered. A fast two-dimensional scanning micromirror is employed to steer the laser beam. A simple experimental setup is built to demonstrate the application of our technique in a two-dimensional laser picture projection. Experimental results show that the speckle contrast factor can be reduced down to 5% within the integration time of the detector.
96 citations
01 Jan 1995
TL;DR: In this paper, Fourier and Statistical Optics Fourier Optics statistical Optics Turbulence Effects on Imaging Systems Index of Refraction Fluctuations in the Atmosphere Statistics of Index of Reconstant Fluctuation Wave Propagation through Random Media First-Order Turbulences Effects on Incoherent Imaging Modal Expansions of Phase Perturbation Phase Screen Generation Speckle Imaging Techniques Introduction Overview of Speckles Imaging SpeckLE Interferometry Fourier Phase Estimation Techniques Image Reconstruction for Specksle Imaging Conclusion Adaptive Optical Imaging Systems Introduction Factors
Abstract: Introduction Overview of the Problem Area Historical Overview of Imaging Through Turbulence Overview of the Book Background: Fourier and Statistical Optics Fourier Optics Statistical Optics Turbulence Effects on Imaging Systems Index of Refraction Fluctuations in the Atmosphere Statistics of Index of Refraction Fluctuations Wave Propagation through Random Media First-Order Turbulence Effects on Incoherent Imaging Modal Expansions of Phase Perturbation Phase Screen Generation Speckle Imaging Techniques Introduction Overview of Speckle Imaging Speckle Interferometry Fourier Phase Estimation Techniques Image Reconstruction for Speckle Imaging Conclusion Adaptive Optical Imaging Systems Introduction Factors that Degrade AOI Systems Performance Adaptive Optical System Components and Models AOI System Performance Modeling Summary Hybrid Imaging Techniques Introduction Deconvolution from Wavefront Sensing Methods Involving Adaptive Optics Conclusion Index
96 citations
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TL;DR: In this article, the authors used speckle imaging to monitor 20 T Tauri binary stars with separations ranging from 0".09 to 1" (13-140 AU) and demonstrated that the majority of the observed systems show significant relative velocities which are not consistent with the motion expected for HH objects, and thus are not the result of differential proper motion, and are consistent with orbital motion.
Abstract: Over a five year period, we have used speckle imaging to monitor 20 T Tauri binary stars with separations ranging from 0".09 to 1" (13-140 AU). This project is aimed at detecting the relative motion of the component stars to ascertain whether or not the observed companions (1) are stellar in nature, as opposed to being HH objects, and (2) are gravitationally bound to the primary stars. These observations demonstrate that speckle imaging measurements of close binary stars' separations can be made with an accuracy of a few milliarcseconds. The majority of the observed systems show significant relative velocities which (1) are not consistent with the motion expected for HH objects, (2) are greater than the velocity dispersion of these star-forming regions and thus are not the result of differential proper motion, and (3) are consistent with orbital motion. This is the first demonstration that these systems are physically bound. Furthermore, these relative velocity measurements provide dynamical evidence that the average total mass of these T Tauri binary star systems is ~l.7M_⊙.
95 citations