891 resultados para Karhunen-Loève transform
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Kirje 16.10.1967
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Kirje 8.11.1958
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This paper argues that Malthusian regimes are capable of sustained changes in per capita incomes. Shifting mortality and fertility schedules can lead to different steady-state income levels, with long periods of growth during the transition. Europe checked the downward pressure on wages through late marriage, which reduced fertility, and a mortality regime that combined high death rates with high incomes. We argue that both emerged as a result of the Black Death.
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The aim of this article is to show how, although the evident idealization of Greece and Platonic love throughout the Victorian-Edwardian England, both also show their limits. In order to make it clear the author refers constantly to the implicit Greek texts such as Plato's Symposium and Phaedrus and perhaps even to Plutarch¿s Eroticus in search of a Classical Tradition which is highly significant in order to understand that England at the beginning of the twentieth century.
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Amb ocasió del simposi internacional dedicat a l'amor a Plutarc, aquest treball fou presentat per mostrar fins a quin punt Plutarc, sobre tot al seu Eròtic i des de paràmetres estrictament platònics, amb l'ajut d'una lògica elemental i alhora rigorosa, es limita a corregir platònicament Plató per tal que éros i philía puguin ser atribuïts també al amor conjugal.
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We propose a method to obtain a single centered correlation with use of a joint transform correlator. We analyze the required setup to carry out the whole process optically, and we also present experimental results.
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It is possible to improve the fringe binarization method of joint transform correlation by choosing a suitable threshold level.
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In multiobject pattern recognition the height of the correlation peaks should be controlled when the power spectrum of ajoint transform correlator is binarized. In this paper a method to predetermine the value of detection peaks is demonstrated. The technique is based on a frequency-variant threshold in order to remove the intraclass terms and on a suitable factor to normalize the binary joint power spectrum. Digital simulations and experimental hybrid implementation of this method were carried out.
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The use of different kinds of nonlinear filtering in a joint transform correlator are studied and compared. The study is divided into two parts, one corresponding to object space and the second to the Fourier domain of the joint power spectrum. In the first part, phase and inverse filters are computed; their inverse Fourier transforms are also computed, thereby becoming the reference in the object space. In the Fourier space, the binarization of the power spectrum is realized and compared with a new procedure for removing the spatial envelope. All cases are simulated and experimentally implemented by a compact joint transform correlator.
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We report the study of the influence of optical aberrations in a joint-transform correlator: The wave aberration of the optical system is computed from data obtained by ray tracing. Three situations are explored: We consider the aberration only in the first diffraction stage (generation of power spectrum), then only in the second (transformation of the power spectrum into correlation), and finally in both stages simultaneously. The results show that the quality of the correlation is determined mostly by the aberrations of the first diffraction stage and that we can optimize the setup by moving the cameras along the optical axis to a suitable position. The good agreement between the predicted data and the experimental results shows that the method explains well the behavior of optical diffraction systems when aberrations are taken into account.
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This article summarizes the basic principles of Fourier Transform Infrared Spectroscopy, with examples of methodologies and applications to different field sciences.