نتایج جستجو برای: dimensional speckle

تعداد نتایج: 406318  

2016
Guy Satat Barmak Heshmat Tristan Swedish Ramesh Raskar

We demonstrate an endoscopic imaging system for microscopic flow measurement (for example blood flow in tissue) using laser speckle contrast imaging. Computational imaging is used to reject sub-surface scattering and eliminates erroneous flow speed estimation. OCIS codes: (110.6150) Speckle imaging; (110.1758) Computational imaging; (170.2150) Endoscopic imaging

Journal: :Optics letters 2006
Pavel Zakharov Andreas Völker Alfred Buck Bruno Weber Frank Scheffold

We have analyzed the image formation and dynamic properties in laser speckle imaging (LSI) both experimentally and with Monte Carlo simulation. We show for the case of a liquid inclusion that the spatial resolution and the signal itself are both significantly affected by scattering from the turbid environment. Multiple scattering leads to blurring of the dynamic inhomogeneity as detected by LSI...

Journal: :IEEE Trans. Geoscience and Remote Sensing 1999
Roger Fjørtoft Armand Lopes Jérôme Bruniquel Philippe Marthon

| We here develop optimal criteria for detection and localization of step edges in single look complex (SLC) synthetic aperture radar (SAR) images. By working on complex data rather than intensity images, we can easily take the speckle autocorrelation into account, obtain more accurate estimates of local mean reeectivities, and thus achieve better edge detection and edge localization than with ...

Journal: :European journal of echocardiography : the journal of the Working Group on Echocardiography of the European Society of Cardiology 2009
Tomoko Nishikage Hiromi Nakai Victor Mor-Avi Roberto M Lang Ivan S Salgo Scott H Settlemier Stephane Husson Masaaki Takeuchi

AIMS Two-dimensional speckle tracking echocardiography (2DSTE) allows measurements of left ventricular (LV) volumes and LV ejection fraction (LVEF) without manual tracings. Our goal was to determine the accuracy of 2DSTE against real-time 3D echocardiography (RT3DE) and against cardiac magnetic resonance (CMR) imaging. METHODS AND RESULTS In Protocol 1, 2DSTE data in the apical four-chamber v...

Journal: :Journal of biomedical optics 2011
Yuuki Watanabe Haruyuki Hasegawa Seiya Maeno

We demonstrate speckle reduction based on angular compounding using parallel-detection spectral-domain optical coherence tomography (OCT). An ultrahigh-speed two-dimensional complementary metal-oxide semiconductor camera acquired angular and spectral interference fringes (128 × 1024 pixels) simultaneously at 15,000 frames/s for a single lateral point. A signal-to-noise ratio improvement of 8 dB...

Journal: :Physical review letters 2005
C Fort L Fallani V Guarrera J E Lye M Modugno D S Wiersma M Inguscio

We investigate the one-dimensional expansion of a Bose-Einstein condensate in an optical guide in the presence of a random potential created with optical speckles. With the speckle the expansion of the condensate is strongly inhibited. A detailed investigation has been carried out varying the experimental conditions and checking the expansion when a single optical defect is present. The experim...

2010
Robert Filter Toralf Scharf Hans Peter Herzig

We propose a simple reflection measurement setup and a motion evaluation procedure based on a two dimensional recording of subsequent speckle images. The averaging of cross correlation functions is used to measure displacements. We demonstrate experimentally a 10 nm precision on a 50 μm measurement range limited by systematical errors. An image library is proposed to extend the measurement rang...

2017
Haiyan Li Jun Wu Aimin Miao Pengfei Yu Jianhua Chen Yufeng Zhang

BACKGROUND Ultrasound imaging plays an important role in computer diagnosis since it is non-invasive and cost-effective. However, ultrasound images are inevitably contaminated by noise and speckle during acquisition. Noise and speckle directly impact the physician to interpret the images and decrease the accuracy in clinical diagnosis. Denoising method is an important component to enhance the q...

2014
Antonio Vitarelli Francesco Martino Lidia Capotosto Eliana Martino Chiara Colantoni Rasul Ashurov Serafino Ricci Ysabel Conde Fabio Maramao Massimo Vitarelli Stefania De Chiara Cristina Zanoni Xiaowen Hu.

Dyslipidemia and obesity are considered strong risk factors for premature atherosclerotic cardiovascular disease and increased morbidity and mortality and may have a negative impact on myocardial function. Our purpose was to assess the presence of early myocardial deformation abnormalities in dyslipidemic children free from other cardiovascular risk factors, using 2-dimensional speckle tracking...

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