Search results for " Spectra"
showing 10 items of 709 documents
The use of vineyard spectral signatures to identify table grape cultivars
2021
Vineyards have characteristic responses to sunlight. The reflectance values at the different wavelengths are typical of vegetation and define its spectral signature. The aim of this work was to determine the spectral signatures of table grape vineyards located in the production area of Robinvale (Victoria, Australia) in order to identify cultivars in the vineyard. Spectral signatures were detected from images in eight bands from the Worldview 3 platform. Spectral signatures for a representative number of plots were extracted using satellite reflectance images for each cultivar. Spectral signatures were also collected in the field, from the same cultivars, with a FieldSpec® HandHeld 2 portab…
A low-cost multispectral imaging system for the characterisation of soil and small vegetation properties using visible and near-infrared reflectance
2022
Current Proximal Sensing technologies are based on multispectral imaging systems able to capture images in a few spectral bands, usually centred in VIS and NIR regions, to derive vegetation indices. However, most of such systems lack an internal radiometric calibration to estimate the actual reflectance of the observed target, making them sensitive to the local radiative environment and requiring a per-session calibration against a reference target. To overcome such dependence, the instrument described adopts an active illumination of the target surface, allowing the monitoring of soil and low vegetation surfaces by a radiometrically pre-calibrated imaging camera. The system, driven by a mi…
Metodo per il monitoraggio di superfici vegetali
2019
Si descrive un metodo da impiegare per la caratterizzazione delle coperture vegetali. A method to be used for the monitoring of vegetation surfaces is described, which includes the use of a device for measuring the spectral reflectance of vegetation using images acquired with a lightening system based on visible and infrared monoband LEDs and including devignetting, image cropping, radiometric calibration procedures and calculation of reflectance values and vegetation indices.
Method for monitoring vegetation ground covers
2020
A method to be used for the monitoring of vegetation surfaces is described, which includes the use of a device for measuring the spectral reflectance of vegetation using images acquired with a lightining system based on visible and infrared monoband LEDs and including devignetting, image cropping, radiometric calibration procedures and calculation of reflectance values and vegetation indices.
Dispositivo per il monitoraggio di superfici vegetali
2017
La presente invenzione si riferisce al settore della diagnostica ambientale poiché fornisce un dispositivo che consente il monitoraggio dello stato fisiologico dei tappeti erbosi e di altre tipologie di coperture naturali che può essere anche impiegato per una accurata caratterizzazione e gestione delle coperture vegetali quali ad esempio campi sportivi, aree verdi naturali o artificiali e il relativo metodo.
Electronic ionization mass spectra of 3-(5'-(3'-methylisoxazol))- and 3-(3'-(5'-methylisoxazol)-2-styryl-4(3H)quinazolinones of pharmaceutical intere…
2008
Role of Ce3+ as sensitizer for the infrared luminescence of phosphosilicate Er/Yb doped glasses
2012
The luminescence properties of the Yb/Er-doped phosphosilicate preforms used for the design of active optical fibers were investigated under a tunable laser excitation from ultraviolet to infrared domain. We demonstrated that codoping the glass matrix with Ce3+ ions strongly influences the infrared emission associated with Er3+ ions, it enhances the energy transfer from Yb3+ to Er3+ ions, and it provides an additional ultraviolet excitation channel for the emission of both Yb3+ and Er3+ ions. The excitation/emission pathways are discussed on the basis of models proposed in literature for other systems.
H2 Molecule Driven by a Laser Field
2008
We study the single and double ionization yields and the dissociation dynamics of a one-dimensional two-electron molecule exposed to a laser pulse of intensity IL in the range 1013 − 1015 W/cm2 and photon energy hω¯L =3.18 eV. The calculations are carried out in the case of both fixed and movable nuclei. At low IL the ionization curves have a power law shape In that is interrupted by a knee at higher intensity.