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: The measurements of positional parameters of 194 nearby binary stars performed at the 6m BTA telescope of the SAO RAS from 2002 through 2006 applying the speckle interferometric technique were conducted at central filter wavelengths ranging from 545 to 800 nm as discussed by the authors.
Abstract: We present the measurements of positional parameters of 194 nearby binary stars performed at the 6-m BTA telescope of the SAO RAS from 2002 through 2006 applying the speckle interferometric technique. The observations were conducted at central filter wavelengths ranging from 545 to 800 nm using a speckle interferometer equipped with a fast CCD and a three-stage image intensifier. A significant part of the observed systems (80 stars) are pairs, the duality of which was discovered or suspected from the Hipparcos satellite observations. The remaining stars are visual binaries and interferometric binary systems with orbital motion period estimates from several to tens of years, as well as the pairs with slow relative motion of the components, used for gaging the image scales and positional angle calibrations.
40 citations
TL;DR: In this paper, the mean, the variance, and the correlation function of the intensity pattern resulting from an incoherent source that has propagated through a complex ABCD optical system are derived.
Abstract: The mean, the variance, and the correlation function of the intensity pattern resulting from an incoherent source that has propagated through a complex ABCD optical system are derived. The number of speckle correlation cells (or modes, N) within an effective measurement area is presented and discussed. Optical field decorrelation effects with respect to secondary fringe formation in phase-shifting speckle interferometry are discussed. In particular, the correlation coefficient resulting from load-induced object tilt, in-plane translations, and displacements parallel to the optic axis as a function of the number of modes propagating through the optical system is derived and discussed. In contrast to previous research, in which the calculation of speckle interferometric decorrelation effects was restricted to direct imaging systems and the special case where N → ∞, the correlation coefficients that we derive are valid for arbitrary complex ABCD systems (i.e., nonimaging configurations) and for all finite values of N ≥ 1.
40 citations
TL;DR: In this paper, a phase unwrapping software has been developed using discrete cosine transform (DCT) to generate the three-dimensional (3-D) profiles of the machined surface.
40 citations
TL;DR: The contrast of the fringes obtained with extra phase steps along with incoherent superimposition is shown to be higher than the single- or four-phase-step method.
Abstract: A detailed analysis of the vibration fringes obtained by phase stepping on a time-averaged electronic speckle pattern interferometer is presented. It is shown that the contrast of the fringes remains relatively high for any phase step between 30° and 180° for low electronic noise and fringe density. Also, for the four-phase-stepped method, the vibration fringes have the same contrast as that of the π-phase-shift method except that the high-frequency speckles are smoothed. The contrast of the fringes obtained with extra phase steps along with incoherent superimposition is shown to be higher than the single- or four-phase-step method. Both theory and experimental results are presented.
39 citations
TL;DR: In this article, the statistical distribution of the background intensity and the modulation is derived for an arbitrary number n of speckles per pixel, for both the speckle and the smooth reference wave setup.
39 citations