نتایج جستجو برای: optical techniques

تعداد نتایج: 875271  

Journal: :Journal of Optical Communications and Networking 2021

Having ubiquitous optical monitors in dense wavelength-division multiplexing (DWDM) or flex-grid networks allows the estimation real time of crucial parameters. Such monitoring would be even more important disaggregated networks, to inspect performance issues related inter-vendor interoperability. Several parameters can retrieved using spectrum analyzers (OSAs). However, omnipresent OSAs repres...

Journal: :Chinese Physics 2023

Computational imaging enables optical systems to acquire more information with miniaturized setups. can avoid the object-image conjugate limitation of system, and introduce encoding decoding processes based on physical optics achieve efficient transmission. It simultaneously increase amount reduce complexity thereby paving way for miniaturizing systems. Based computational imaging, simple compa...

Journal: :Current opinion in neurobiology 2013
Yicong Wu Ryan Christensen Daniel Colón-Ramos Hari Shroff

Over the past decade, developmental neuroscience has been transformed by the widespread application of confocal and two-photon fluorescence microscopy. Even greater progress is imminent, as recent innovations in microscopy now enable imaging with increased depth, speed, and spatial resolution; reduced phototoxicity; and in some cases without external fluorescent probes. We discuss these new tec...

2002
Guang S. He

Over the last three decades, optical phase conjugation (OPC) has been one of the major research subjects in the field of nonlinear optics and quantum electronics. OPC defines usually a special relationship between two coherent optical beams propagating in opposite directions with reversed wave front and identical transverse amplitude distributions. The unique feature of a pair of phase-conjugat...

2009
René M. de Ridder Wico C.L. Hopman Edwin J. Klein

Optical microresonators that are coupled to optical waveguides often behave quite similar to Fabry-Perot resonators. After summarising key properties of such resonators, three characterization methods will be discussed. The first involves the analysis of transmission and reflection spectra, from which important parameters like (waveguide) loss and coupling or reflection coefficients can be extr...

2002
Rick Gaudette

Three-dimensional diffuse optical tomography (DOT) attempts to map in vivo tissue blood oxygenation and blood volume levels by reconstructing the spatial distribution of the optical absorption coefficient from intensity measurements on the surface of the body. This problem is typically ill-posed due to the large attenuation and scattering of the diffuse wave. In addition, certain applications, ...

2009
A. A. Shafie Fadhlan Hafiz M. H. Ali

Motion detection is very important in image processing. One way of detecting motion is using optical flow. Optical flow cannot be computed locally, since only one independent measurement is available from the image sequence at a point, while the flow velocity has two components. A second constraint is needed. The method used for finding the optical flow in this project is assuming that the appa...

1995
Ravi Krishnamurthy Pierre Moulin John W. Woods

Motion estimation is an important part of most video coding schemes because it enables us to exploit the high degree of temporal redundancy present. Though block matching algorithms (BMA) yield coarse and piecewise-constant elds, they are very popular due to their simplicity and low bit overhead. In this paper, we propose to use a more advanced gradient-based technique to overcome the disadvant...

2001
A. W. DAVIS M. J. PETTITT

Abstruct-In the present state of the art, coherent optical receivers most often operate in the heterodyne mode. Here a photodiode-,amplifier combination having bandwidth greater than twice the bit rate ( B ) is needed: indeed bandwidths considerably greater than 2B are preferably employed to ease design of the bandpass filter needed for noise limitation, and to avoid demodulator penalties in so...

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