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Speckle imaging

About: Speckle imaging is a research topic. Over the lifetime, 3730 publications have been published within this topic receiving 62354 citations.


Papers
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Journal ArticleDOI
TL;DR: An efficient method to reduce the noise from electrical speckle pattern interferometry (ESPI) phase fringe patterns obtained by any technique and can overcome the main disadvantages encountered by the two methods.
Abstract: An efficient method is proposed to reduce the noise from electrical speckle pattern interferometry (ESPI) phase fringe patterns obtained by any technique. We establish the filtering windows along the tangent direction of phase fringe patterns. The x and y coordinates of each point in the established filtering windows are defined as the sine and cosine of the half-wrapped phase multiplied by a random quantity, then phase value is calculated using these points' coordinates based on a least-squares fitting algorithm. We tested the proposed methods on the computer-simulated speckle phase fringe patterns and the experimentally obtained phase fringe pattern, respectively, and compared them with the improved sine/cosine average filtering method [Opt. Commun. 162, 205 (1999)] and the least-squares phase-fitting method [Opt. Lett. 20, 931 (1995)], which may be the most efficient methods. In all cases, our results are even better than the ones obtained with the two methods. Our method can overcome the main disadvantages encountered by the two methods.

23 citations

Proceedings ArticleDOI
27 May 2003
TL;DR: In this paper, a new automatic phase FFT filtration method is described, which is applied on interferograms obtained through one dimensional folding shear interferometry for displacements measurement of a loaded glass flask.
Abstract: In this article a new automatic phase FFT filtration method is described. It is compared with other well known filtration techniques for noise removal. This automatic FFT filter is applied on interferograms obtained through one dimensional folding shear interferometry for displacements measurement of a loaded glass flask. Different algorithms have been applied for processing of digitally synthesized phase maps and the advantages of the enhanced automatic FFT filtration are shown. The phase filtered maps obtained in this way can be demodulated even with the simplest unwrapping technique.

23 citations

Journal ArticleDOI
TL;DR: In this article, the influence of the telescope diameter on solar observations is shown graphically, and predictions for the observed contrast in solar granulation are made as a function of wavelength.
Abstract: Fried's seeing parameter r 0 can be determined from the observed r.m.s. contrast of solar granulation. The computation is based on results obtained from solar speckle interferometry. The influence of the telescope diameter on solar observations is shown graphically, and predictions for the observed contrast in solar granulation are made as a function of wavelength. The importance of seeing conditions is discussed, and a conclusion is made on the optimum telescope size to be used for given turbulence conditions

23 citations

Journal ArticleDOI
TL;DR: Theoretical analysis and experimental investigations reveal that an almost diffraction-limited performance in speckle metrology can be achieved over the entire object field that can be imaged by this hololens configuration.
Abstract: Use of a two hololens imaging system in speckle metrology is studied in detail. Theoretical analysis and experimental investigations reveal that an almost diffraction-limited performance in speckle metrology can be achieved over the entire object field that can be imaged by this hololens configuration.

23 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe the application of TV holography, also known as electronic speckle pattern interferometry (ESPI), to the examination of wall paintings.
Abstract: The authors describe the application of TV holography, also known as electronic speckle pattern interferometry (ESPI), to the examination of wall paintings. The equipment usesfibre-optic illumination and a solid-state camera connected to a computer. Images made after the wall painting has been warmed slightly with an infrared lamp are compared with reference images; differences in the speckle pattern can be used to identify cracks and subsurface detachments. The system is robust and portable, allowing it to be used for the in situ investigation of wall paintings, including those exposed externally. It can also be used to monitor the condition of the work of art over time and to evaluate the success of any treatment.

23 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202332
202249
202162
202079
201972
201895