Search results for "light"

Il Medium come Habitat. Tecnologia e sensibilità nell'esperienza artistica dell’Expanded Cinema e del Light & Space Movement.

L’intenzione alla base della mia proposta teorica, che ho definito appunto “il medium come habitat”, è quella di riattualizzare la questione della medialità in relazione ad un habitat che non deve essere esclusivamente inteso come ambiente naturale (quello dell’ecologia) o come ambiente sociale (dell’antropologia o della sociologia). L’habitat piuttosto è da considerarsi come un campo esperienziale attraversato e definito da relazioni in continuo divenire, radicate in primo luogo nel rapporto sensibile e affettivo, estetico che mette in comunicazione tra loro i vari elementi, e questi ultimi con l’habitat che essi popolano. Le strategie di organizzazione e attribuzione di senso alla realtà …

Suppression of the speckle noise in solid polymer samples: a light scattering study

1994

The speckle effect disturbs the measurement of spatial correlation functions in solid polymer samples by light scattering. To be able to extract the desired correlations from the measurements, the speckle noise must be suppressed. This is possible by moving the sample during the measurement. In this paper we demonstrate that a sufficient reduction of speckle contrast can be achieved even in samples of restricted dimensions or with a preferential direction.

Single-channel polychromatic pattern recognition by the use of a joint-transform correlator.

2010

We present a single-channel system for color image recognition that is based on a joint-transform correlator setup. The color images are encoded as phase and amplitude functions, inspired from the Munsell color representation. A real-time implementation of the new codification method can be achieved by the use of a spatial light modulator operating in phase-only modulation mode. We determine the optimal codification for a linear color-phase code. Its performance is compared with a conventional multichannel correlator by means of computer simulations. Experimental results are also presented.

Dispersion management in two-photon microscopy by using diffractive optical elements.

2013

We demonstrate efficient generation of wide-field fluorescence signals in two-photon microscopy exploiting diffractive optical elements and short pulses by using a dispersion-compensated beam delivery optics module. Computer-generated holograms are codified onto a phase-only spatial light modulator, which allows for arbitrary single-shot patterning of the sample. Spatiotemporal shaping of the pulse is mandatory to overcome spatial chirp and pulse-front tilt effects that spread both in space and time the irradiance patterns, thus limiting not only the spatial resolution but also the signal-to-noise ratio in two-photon microscopy. By using a multipass amplifier delivering 30 fs, 0.8 mJ pulses…

Dynamical binary modulation of ultrabroadband light beams by using principal states of polarization of liquid crystal devices

2009

Dynamical modulation of ultrabroadband beams, such as those produced by femtosecond laser or incoherent sources, is not an easy task due to the dispersive nature of the devices commonly employed. Phase modulation has been performed by means of deformable micromirror arrays. These devices are expensive and do not permit amplitude modulation. For micro- and nano-structuring of materials with femtosecond lasers is common to pattern the surface with the light irradiance produced by a computer generated hologram implemented onto a liquid crystal (LC) type spatial light modulator. This enables dynamical patterning [1,2]. Reduced spectral bandwidths, of the order of tens of nanometers, have been u…

Super Resolution Methods Implementing Diffractive Masks Having a Certain Degree of Periodicity

2011

This section presents an approach that provides super resolved imaging at the center of the field of view and yet allows to see the remaining of the original field of view with original resolution. This operation resembles optical zooming while the zoomed and the nonzoomed images are obtained simultaneously. This is obtained by taking a single snap-shot and using a single imaging lens. The technique utilizes a special static/still coding element and a postprocessing algorithmic, without any mechanical movements.

Multi-speckle autocorrelation spectroscopy — a new strategy to monitor ultraslow dynamics in dense and nonergodic media

2007

We present a modification of the conventional dynamic light scattering set-up which allows to monitor the intensity fluctuations of many independent spatial Fourier components of the density fluctuations, i.e. “speckles”, simultaneously by using a charge-coupled device (CCD) camera as area detector. By averaging over the intensity autocorrelation function the final 10–20% decay of the intermediate scattering function in very dense colloidal dispersions is obtained with much higher accuracy. At the same time this multi-speckle autocorrelation spectroscopy provides an alternative route for constructing ensemble-averaged intermediate scattering functions in nonergodic media by replacing the av…

The colour of light for urban spaces

2013

Light in urban spaces was first introduced to prevent crimes against both people and properties and, while there is no study that confirms crimes' reduction in lit spaces, it is undeniable that people feel safer in lit urban spaces. Over the years it became evident that light can also improve the liveability of cities and enhance their characteristics, therefore in the last years a growing attention was paid to urban lighting design taking into account the environmental impact and energy saving requirements too. The will to use the lighting design project to improve the liveability of historical centres it’s clear: the city during the night is no more conceived like a sum of lit architectur…

Spectral Transmission of the Human Corneal Layers

2021

Este artículo se encuentra disponible en la siguiente URL: https://www.mdpi.com/2077-0383/10/19/4490 Este artículo de investigación pertenece a la sección "Ophthalmology". We have assessed the spectral transmittance of the different layers of the human cornea in the ultraviolet (UV), visible, and near-infrared (IR) spectral ranges. Seventy-four corneal sample donors were included in the study. Firstly, the corneal transmittance was measured using a spectrophotometer. Then, all samples were fixed for histopathological analysis, which allowed us to measure the thickness of each corneal layer. Finally, the absorption coefficients of the corneal layers were computed by a linear model reproducin…

Rapid and Nondestructive Determination of Egg Freshness Category and Marked Date of Lay using Spectral Fingerprint

2020

The potential of nondestructive prediction of egg freshness based on near-infrared (NIR) spectra fingerprints would be beneficial to quality control officers and consumers alike. In this study, handheld NIR spectrometer in the range of 740 nm to 1070 nm and chemometrics were used to simultaneously determine egg freshness based on marked date of lay for eggs stored under cold and ambient conditions. The spectra acquired from the eggs were preprocessed using multiplicative scatter correction and principal component analysis (MSC-PCA). Linear discriminant analysis (LDA) was used to build identification model to predict the category of freshness, while partial least square regression (PLS-R) wa…