Superresolution: an ill-posed problem in Fourier optics

info:eu-repo/semantics/published

On the problems of object restoration and image extrapolation in optics

In this paper we consider the problems of object restoration and image extrapolation, according to the regularization theory of improperly posed problems. In order to take into account the stochastic nature of the noise and to introduce the main concepts of information theory, great attention is devoted to the probabilistic methods of regularization. The kind of the restored continuity is investigated in detail; in particular we prove that, while the image extrapolation presents a Hölder type stability, the object restoration has only a logarithmic continuity. © 1979 American Institute of Physics.

On the regularization of linear inverse problems in Fourier optics

info:eu-repo/semantics/published

Applied Inverse Problems in Optics

info:eu-repo/semantics/published

Experimental Studies of the Coherence of Microstructure-Fiber Supercontinuum

The phase coherence of supercontinuum generation in microstructure fiber is quantified by performing a Young's type interference experiment between independently generated supercontinua from two separate fiber segments. Analysis of the resulting interferogram yields the wavelength dependence of the magnitude of the mutual degree of coherence, and a comparison of experimental results with numerical simulations suggests that the primary source of coherence degradation is the technical noise-induced fluctuations in the injected peak power. © 2003 Optical Society of America.

Cross-correlation frequency resolved optical gating analysis of broadband continuum generation in photonic crystal fiber: Simulations and experiments

Numerical simulations are used to study the temporal and spectral characteristics of broadband supercontinua generated in photonic crystal fiber. In particular, the simulations are used to follow the evolution with propagation distance of the temporal intensity, the spectrum, and the cross-correlation frequency resolved optical gating (XFROG) trace. The simulations allow several important physical processes responsible for supercontinuum generation to be identified and, moreover, illustrate how the XFROG trace provides an intuitive means of interpreting correlated temporal and spectral features of the supercontinuum. Good qualitative agreement with preliminary XFROG measurements is observed. © 2002 Optical Society of America.

Imátgenes 19, 20 y 21

Por quinta vez puso cuatro motas de tinta en el papel, les puso nombres (A, B, C, D) y los unió con segmentos para formar un cuadrilátero. Luego señaló los puntos medios de sus cuatro lados y los conectó formando otro cuadrilátero (P, Q, R, S). Ahí estaba el problema. Ese cuadrilátero interior siempre resultaba ser un paralelogramo pusiera como pusiera los cuatro puntos originales. ¿Acaso había orden en el caos? Por un momento pensó que quizá había truco, que tal vez sucedía así porque la gente ponía los puntos de formas similares. Pero ya había probado configuraciones muy raras, incluso dejó que los segmentos del cuadrilátero ABCD se interceptasen, y siempre obtenía idéntico resultado. No, lo que parece cumplirse para cualquier caso no es ningún truco, sino un teorema que demostrar.

Identification of the copepodite developmental stages of twenty-six North Atlantic copepods. Occasional Publication of the Marine Biological Association 21.

In zooplankton copepod studies there is often the requirement to be able to identify the six copepodite developmental stages of different species, or to know their body dimensions. However, this information is not available for many species, or is dispersed through the literature. This guide gathers together both original and previously published information on morphology and measurements for the stages of twenty-six common North Atlantic copepod species and tabulates them in a standard format. For each species additional notes useful in their identification are also given.