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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20 Oct 2017
TL;DR: This work demonstrates a single-shot multispectral imaging technique that gives flexibility to end users with a very simple optical setup, thanks to spatial correlation and spectral decorrelation of speckle patterns.
Abstract: Multispectral imaging plays an important role in many applications, from astronomical imaging and earth observation to biomedical imaging. However, current technologies are complex with multiple alignment-sensitive components and spatial and spectral parameters predetermined by manufacturers. Here, we demonstrate a single-shot multispectral imaging technique that gives flexibility to end users with a very simple optical setup, thanks to spatial correlation and spectral decorrelation of speckle patterns. These seemingly random speckle patterns are point spread functions (PSFs) generated by light from point sources propagating through a strongly scattering medium. The spatial correlation of PSFs allows image recovery with deconvolution techniques, while the spectral decorrelation allows them to play the role of tunable spectral filters in the deconvolution process. Our demonstrations utilizing optical physics of strongly scattering media and computational imaging present a cost-effective approach for multispectral imaging with many advantages.
113 citations
TL;DR: In this paper, the authors presented 2017 observations of 1286 binary stars, observed by means of speckle interferometry using six telescopes over a 15-year period from 1982 April to 1997 June.
Abstract: We present 2017 observations of 1286 binary stars, observed by means of speckle interferometry using six telescopes over a 15 year period from 1982 April to 1997 June. These measurements constitute the 23d installment in CHARA's speckle program at 2 to 4 m class telescopes and include the second major collection of measurements from the Mount Wilson 100 inch (2.5 m) Hooker Telescope. Orbital elements are also presented for 14 systems, seven of which have had no previously published orbital analyses.
113 citations
TL;DR: The MESI technique was used to image the blood flow changes in a mouse cortex following photothrombotic occlusion of the middle cerebral artery and estimates of these flow changes were found to be unaffected by scattering from thinned skull.
Abstract: Laser Speckle Contrast Imaging (LSCI) has become a widely used technique to image cerebral blood flow in vivo. However, the quantitative accuracy of blood flow changes measured through the thin skull has not been investigated thoroughly. We recently developed a new Multi Exposure Speckle Imaging (MESI) technique to image blood flow while accounting for the effect of scattering from static tissue elements. In this paper we present the first in vivo demonstration of the MESI technique. The MESI technique was used to image the blood flow changes in a mouse cortex following photothrombotic occlusion of the middle cerebral artery. The Multi Exposure Speckle Imaging technique was found to accurately estimate flow changes due to ischemia in mice brains in vivo. These estimates of these flow changes were found to be unaffected by scattering from thinned skull.
112 citations
TL;DR: In this article, a new method of observing vibration fringes is presented and compared with existing techniques as well as some variations on them, which involves continuously subtracting a reference frame containing only self-interference terms and no cross interference term from the time-averaged data frames of the vibrating object.
Abstract: Vibration observation is a major application of digital speckle-pattern interferometry (DSPI), which is a variation on electronic speckle-pattern interferometry (ESPI). DSPI processes speckle patterns in a computer rather than with a frame grabber and analog electronics as in ESPI. A new method of observing vibration fringes is presented and compared with existing techniques as well as some variations on them. Fringe contrast and signal-to-noise ratio are used as a means of comparison since these quantities are dependent on the techniques used. This new technique involves continuously subtracting a reference frame containing only self-interference terms and no cross interference term from the time-averaged data frames of the vibrating object. This reference frame is created by vibrating a reference mirror at a high amplitude while the object is at rest. Comparisons of calculated fringe contrast with four other observation methods show that this method yields extremely good fringe contrast. Experimental results are shown for this new technique as well as for the most commonly used vibration-observation technique. These results show that the new technique is far superior to all the other methods for moderately unstable objects, which may slowly drift or deform in time.
110 citations
TL;DR: A new high-speed method for implementing angular compounding by path length encoding (ACPE) for reducing speckle in OCT images is described, by averaging images obtained at different incident angles, with each image encoded by pathlength.
Abstract: Angular compounding by path length encoding (ACPE), a new method for reducing speckle in OCT images is presented. ACPE images demonstrate a qualitative improvement over traditional OCT and an increased SNR.
110 citations