Search results for "visibility"
showing 10 items of 149 documents
Fog attenuation prediction for optical and infrared waves
2004
The principal disadvantage of using free space optics (FSO) telecommunication systems is the disturbing role played by the atmosphere on light propagation and thus on the channel capacity, availability, and link reliability. The wavelength choice is currently a subject of disagreement among designers and users of FSO equipments. Generally this equipment operates in the visible and the near IR at 690, 780, 850, and 1550 nm. Several authors affirm that equipment working at 1550 nm presents less atmospheric attenuation in the presence of fog and thus better link availability. Others consider that for dense fogs (visibility<500 m), all wavelengths are attenuated in the same way (wavelength inde…
Axial resonance of periodic patterns by using a Fresnel biprism.
2013
This paper proposes a method for the generation of high-contrast localized sinusoidal fringes with spatially noncoherent illumination and relatively high light throughput. The method, somehow similar to the classical Lau effect, is based on the use of a Fresnel biprism. It has some advantages over previous methods for the noncoherent production of interference fringes. One is the flexibility of the method, which allows the control of the fringe period by means of a simple axial shift of the biprism. Second is the rapid axial fall-off in visibility around the high-contrast fringe planes. And third is the possibility of creating fringes with increasing or with constant period as the light bea…
Talbot interferometry: a new geometry
1993
Abstract With the Talbot effect, planes are found where the Fresnel diffraction pattern, of a Ronchi ruling, exhibits zero visibility. These planes are exploited to propose a novel geometry for Talbot interferometry, which has high sensitivity. Experimental verifications are included.
Lau rings: In-register incoherent superposition of radial self-images
1989
Abstract We describe an optical method for obtaining in-register, incoherent superposition of self-images, with radial symmetry. That is, the Lau effect is implemented, either at infinity or at finite distances, in the form of bright and dark rings of high visibility. This is applied for visualizing radially phase structures, with good-signal-to-noise ratio.
A spectral hazy image database
2020
We introduce a new database to promote visibility enhancement techniques intended for spectral image dehazing. SHIA (Spectral Hazy Image database for Assessment) is composed of two real indoor scenes M1 and M2 of 10 levels of fog each and their corresponding fog-free (ground-truth) images, taken in the visible and the near infrared ranges every 10 nm starting from 450 to 1000 nm. The number of images that form SHIA is 1540 with a size of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1312\,\times \,1082$$\end{d…
The Moral Dimension in the Configuration and Historical Evolution of the Concept of Poverty
2015
The phenomenon of poverty shows clearly the overflow of its economic dimension towards a powerful moral dimension, which has caused (and causes) contradictory social attitudes: acceptance or rejection; blaming or understanding; charity or duties, liability or inevitable fate; involvement or alienation; visibility or invisibility. This work analyzes the moral connotations that have been historically forming the concept of poverty to lead the paradigms with which today we conceive it and from which we intend to face it and fight it.
Managing Invisibility: Theoretical and Practical Contestations to Disrespect
2021
By aiming at the recognition of normative claims contained in affective reactions to disrespect or social suffering, Recognition Theory points—at least implicitly—also toward the visibilization of groups and individuals who suffer from disrespect. Social invisibilization is therefore understood as hindering recognition and impeding even the perception of legitimate normative claims. However, since Foucault we also know that visibilization could be a mechanism of control and domination, thus pointing to a form of disrespect as the opposite of recognition. In this chapter the diverse forms of migrants struggle for recognition will be analyzed with regard to the question how these struggles ne…
The OpenUp Process
2014
The Open Unified Process (OpenUp) is an iterative design process that structures the project lifecycle into four phases: Inception, Elaboration, Construction, and Transition. It is part of the Eclipse Process Framework and embraces a pragmatic, agile philosophy that focuses on the collaborative nature of software development. It is a tools-agnostic, low-ceremony process that can be extended to address a broad variety of project types. The project lifecycle provides stakeholders and team members with visibility and decision points throughout the project and makes them able to manage their work through micro-increments.
The Poisson embedding approach to the Calderón problem
2020
We introduce a new approach to the anisotropic Calder\'on problem, based on a map called Poisson embedding that identifies the points of a Riemannian manifold with distributions on its boundary. We give a new uniqueness result for a large class of Calder\'on type inverse problems for quasilinear equations in the real analytic case. The approach also leads to a new proof of the result by Lassas and Uhlmann (2001) solving the Calder\'on problem on real analytic Riemannian manifolds. The proof uses the Poisson embedding to determine the harmonic functions in the manifold up to a harmonic morphism. The method also involves various Runge approximation results for linear elliptic equations.
Non-Markovianity of Gaussian Channels
2015
We introduce a necessary and sufficient criterion for the non-Markovianity of Gaussian quantum dynamical maps based on the violation of divisibility. The criterion is derived by defining a general vectorial representation of the covariance matrix which is then exploited to determine the condition for the complete positivity of partial maps associated to arbitrary time intervals. Such construction does not rely on the Choi-Jamiolkowski representation and does not require optimization over states.