Search results for "Spectral"
showing 10 items of 3116 documents
Development of a multispectral imagery device devoted to weed detection
2003
Multispectral imagery is a large domain with number of practical applications: thermography, quality control in industry, food science and agronomy, etc. The main interest is to obtain spectral information of the objects for which reflectance signal can be associated with physical, chemical and/or biological properties. Agronomic applications of multispectral imagery generally involve the acquisition of several images in the wavelengths of visible and near infrared. This paper will first present different kind of multispectral devices used for agronomic issues and will secondly introduce an original multispectral design based on a single CCD. Third, early results obtained for weed detection…
An Efficient Method for the Visualization of Spectral Images Based on a Perception-Oriented Spectrum Segmentation
2010
We propose a new method for the visualization of spectral images. It involves a perception-based spectrum segmentation using an adaptable thresholding of the stretched CIE standard observer colormatching functions. This allows for an underlying removal of irrelevant channels, and, consequently, an alleviation of the computational burden of further processings. Principal Components Analysis is then used in each of the three segments to extract the Red, Green and Blue primaries for final visualization. A comparison framework using two different datasets shows the efficiency of the proposed method.
Frequency composition of traction and tillage forces on a mole plough
1997
Field experiments were carried out in order to quantify the variations of the traction and tillage forces on a mole plough, in the case of four clayey soils of Eastern France. The same tractor-implement system, the same forward working speed (1 m s−1) and the same length of ploughing (20 m) were used. Specially designed strain gauge transducers applied to the system delivered a signal which was numerised and analysed in terms of power spectral density (PSD) function. The frequency composition of the traction and tillage forces consisted of interactions between soil and tool as well as vibrations of the tractor-implement system. Low frequencies (0–2 Hz range) were related to the random prope…
Optisko metožu un ierīču izstrāde kardiovaskulārā stāvokļa kontrolei reālā laikā
2013
Elektroniskā versija nesatur pielikumus
Analyse spectrale et texturale de données à haute résolution pour la détection automatique des maladies de la vigne
2019
‘Flavescence dorée’ is a contagious and incurable disease present on the vine leaves. In order to contain the infection, the regulations require growers to control each of the vine rows and to remove the suspect vine plants. This monitoring is done on foot during the harvest and mobilizes many people during a strategic period for viticulture. In order to solve this problem, the DAMAV project (Automatic detection of Vine Diseases) aims to develop a solution for automated detection of vine diseases using a micro-drone. The goal is to offer a turnkey solution for wine growers. This tool will allow the search for potential foci, and then more generally any type of vine diseases detectable on th…
Mössbauer-Active Transition Metals Other than Iron
2010
The previous chapters are exclusively devoted to the measurements and interpretation of 57Fe spectra of various iron-containing systems. Iron is, by far, the most extensively explored element in the field of chemistry compared with all other Mossbauer-active elements because the Mossbauer effect of 57Fe is very easy to observe and the spectra are, in general, well resolved and they reflect important information about bonding and structural properties. Besides iron, there are a good number of other transition metals suitable for Mossbauer spectroscopy which is, however, less extensively studied because of technical and/or spectral resolution problems. In recent years, many of these difficult…
Semisynthesis of new tetrahydrofuranic alkyl ester and furano-pyrone derivatives as inhibitors of the mitochondrial complex I
2002
Abstract Methoxymethylation of altholactone ( 1 ) led to the corresponding O -methoxymethyl derivative ( 3 ) in addition to the unexpected 6,7-dihydro-7-methoxy analogue ( 4 ), and two original tetrahydrofuranic (THF) alkyl esters ( 5 , 6 ). Moreover, when we accomplished a new method for the preparation of the furano-pyrone goniofupyrone ( 7 ) through 7-hydroxylation of 1 in acid medium, a minor compound ( 8 ) with an identical skeleton to that of compounds 5 and 6 was identified. Careful examination of the published spectral data of the reported styryl-lactones with an heptolide skeleton reveals that those structures possess also a THF alkyl ester skeleton. The revision of those structure…
Molecular structures and vibrations of m-methylaniline in the S0 and S1 states studied by laser induced fluorescence spectroscopy and ab initio calcu…
2000
Abstract The UV fluorescence excitation and dispersed fluorescence spectra of a jet-cooled m-methylaniline have been obtained for the S1←S0 transition, in which some of the bands have been observed for the first time. The main spectral bands have been assigned by comparison with those of other relevant substituted benzenes. It was found that the spectra exhibit an important feature which is the internal rotation of the methyl group in the electronic ground and excited states. Ab initio calculations at MP2/6-31G* and CIS/6-31G* show that the optimized structure of m-methylaniline in the ground state is not planar with the amino group having sp3 hybridation-like character due to the existence…
A truncated driven Overhauser effect study of Adriamycin in water: Conformation of the glycosidic linkage
1991
Abstract Truncated driven nuclear Overhauser effect difference spectra have been used to ascertain the conformational characteristics of the glycosidic linkage of Adriamycin in aqueous solution. The “two-spin approximation” has been employed to evaluate the cross-relaxation rates between nearby protons and to obtain the relative internuclear distances. The rotational angles φ1 = C(7)−O(7)−C(1′)−(H1′) and φ2 = H(7)−C(7)−O(7)−C(1′) have also been calculated.
Measurments of collisional line widths in the stimulated Raman Q-branch of the ν1 band of silane
1990
Self-broadened widths of 28SiH4 in the ν1Q-branch have been measured at room temperature (295 K) using high-resolution stimulated Raman Spectroscopy. These collisional widths have been obtained by fitting a super-position of Voigt profiles to the experimental spectra in the pressure range 28–154 Torr. No evidence for line mixing within the tetrahedral components of a Q(J) line has been found. The line broadening coefficients for J up to 13 depend weakly on the rotational quantum number. The mean value is 103.7 × 10−3 cm−1 atm−1.