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Direct analysis in real-time (DART) time-of-flight mass spectrometry (TOFMS) of wood reveals distinct chemical signatures of two species of Afzelia / Peter Kitin in Annals of Forest Science [en ligne], vol 78 n° 2 (June 2021)
Titre : Direct analysis in real-time (DART) time-of-flight mass spectrometry (TOFMS) of wood reveals distinct chemical signatures of two species of Afzelia Type de document : Article/Communication Auteurs : Peter Kitin, Auteur ; Edgard Espinoza, Auteur ; Hans Beeckman, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : Article 31 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] abattage (sylviculture)
[Termes IGN] Afzelia (genre)
[Termes IGN] analyse discriminante
[Termes IGN] apprentissage non-dirigé
[Termes IGN] bois
[Termes IGN] espèce végétale
[Termes IGN] forêt tropicale
[Termes IGN] identification de plantes
[Termes IGN] signature spectrale
[Termes IGN] spectrométrie
[Termes IGN] taxinomie
[Termes IGN] temps réel
Résumé : (Auteur) Distinct chemical fingerprints of the wood of Afzelia pachyloba and A. bipindensis demonstrated an effective method for identifying these two commercially important species. Direct analysis in real-time (DART) time-of-flight mass spectrometry (TOFMS) allowed high-throughput examination of chemotypes with vast potential in taxonomic, ecological, and forensic research of wood.
Context : Afzelia is a genus of valuable tropical timber trees. Accurate identification of wood is required for the prevention of illicit timber trade as well as for certification purposes in the forest and wood products industry. For many years, particular interest has been focused on attempts to distinguish the wood of A. bipindensis Harms from A. pachyloba Harms due to substantial differences in the commercial values of these two species.
Aims : We investigated if wood chemical signatures and microscopy could identify the wood of A. bipindensis and A. pachyloba.
Methods : We used two approaches, namely metabolome profiling by direct analysis in real-time (DART) time-of-flight mass spectrometry (TOFMS) and wood microstructure by light microscopy and SEM. In all, we analyzed samples from 89 trees of A. bipindensis, and A. pachyloba.
Results : The two species could not be separated by the IAWA standard microscopic wood features. SEM analysis showed considerable variation in the morphology of vestured pits; however, this variation was not species-specific. In contrast, DART-TOFMS followed by unsupervised statistics (Discriminant Analysis of Principal Components) showed distinct metabolome signatures of the two species.
Conclusion : DART-TOFMS provides a rapid method for wood identification that can be easily applied to small heartwood samples. Time- and cost-effective classification of wood chemotypes by DART-TOFMS can have potential applications in various research questions in forestry, wood science, tree-ecophysiology, and forensics.
Numéro de notice : A2021-327 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-020-01024-1 Date de publication en ligne : 31/03/2021 En ligne : https://doi.org/10.1007/s13595-020-01024-1 Format de la ressource électronique : URL article Permalink :
in Annals of Forest Science [en ligne] > vol 78 n° 2 (June 2021) . - Article 31[article]Mapping individual tree health using full-waveform airborne laser scans and imaging spectroscopy: A case study for a floodplain eucalypt forest / Iurii Shendryk in Remote sensing of environment, vol 187 (15 December 2016)
Titre : Mapping individual tree health using full-waveform airborne laser scans and imaging spectroscopy: A case study for a floodplain eucalypt forest Type de document : Article/Communication Auteurs : Iurii Shendryk, Auteur ; Mark Broich, Auteur ; Mirela G. Tulbure, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 202 - 217 Note générale : bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] Australie
[Termes IGN] classification orientée objet
[Termes IGN] classification par forêts d'arbres décisionnels
[Termes IGN] dépérissement
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] Eucalyptus (genre)
[Termes IGN] Eucalyptus camaldulensis
[Termes IGN] inondation
[Termes IGN] spectrométrie
Résumé : (auteur) Declining forest health can affect crucial ecosystem functions, such as carbon storage in biomass and soils, the regulation of water regimes, the modulation of regional climate and conservation of biodiversity. Airborne laser scanning (ALS) and imaging spectroscopy (IS) are two potentially complementary remote sensing technologies capable of characterizing and monitoring regional forest health. However, the combined use of ALS and IS data to classify the health of individual trees has not yet been assessed. In this study we propose a new approach utilizing ALS and IS combined to characterize the health of individual trees. Firstly, we applied a recently developed bottom-up individual tree delineation algorithm across a structurally complex floodplain eucalypt forest that has experienced episodes of severe dieback over the past six decades. We further calculated ALS and IS indices for delineated tree crowns and used them as predictor variables in machine learning models. We trained and evaluated an object-oriented random forest classifier against field-measured tree crown dieback and transparency ratios, as indicators of eucalypt tree health and crown density, respectively. Our results showed that dieback levels of individual trees can be classified using ALS and IS with an overall accuracy of 81% and a kappa score of 0.66, while the classification of tree crown transparency levels had an overall accuracy of 70% and a kappa score of 0.5. Returned pulse width, intensity and density related ALS indices were the most important predictors in the tree health classification, as they accounted for > 40% of the variance in the data. At the forest level in terms of dieback, 81.5% of correctly delineated trees were classified as healthy, 12.3% as declining and 6.2% as dying or dead. Dieback occurred primarily in areas that were flooded Numéro de notice : A2016-767 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2016.10.014 En ligne : http://dx.doi.org/10.1016/j.rse.2016.10.014 Format de la ressource électronique : URL article Permalink :
in Remote sensing of environment > vol 187 (15 December 2016) . - pp 202 - 217[article]An interactive tool for semi-automatic feature extraction of hyperspectral data / Zoltan Kovacs in Open geosciences, vol 8 n° 1 (January - July 2016)
Titre : An interactive tool for semi-automatic feature extraction of hyperspectral data Type de document : Article/Communication Auteurs : Zoltan Kovacs, Auteur ; Szilárd Szabó, Auteur Année de publication : 2016 Article en page(s) : pp 493 - 502 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] extraction de traits caractéristiques
[Termes IGN] extraction semi-automatique
[Termes IGN] image hyperspectrale
[Termes IGN] régression
[Termes IGN] spectrométrie
[Termes IGN] VBA
Résumé : (auteur) The spectral reflectance of the surface provides valuable information about the environment, which can be used to identify objects (e.g. land cover classification) or to estimate quantities of substances (e.g. biomass). We aimed to develop an MS Excel add-in – Hyperspectral Data Analyst (HypDA) – for a multipurpose quantitative analysis of spectral data in VBA programming language. HypDA was designed to calculate spectral indices from spectral data with user defined formulas (in all possible combinations involving a maximum of 4 bands) and to find the best correlations between the quantitative attribute data of the same object. Different types of regression models reveal the relationships, and the best results are saved in a worksheet. Qualitative variables can also be involved in the analysis carried out with separability and hypothesis testing; i.e. to find the wavelengths responsible for separating data into predefined groups. HypDA can be used both with hyperspectral imagery and spectrometer measurements. This bivariate approach requires significantly fewer observations than popular multivariate methods; it can therefore be applied to a wide range of research areas. Numéro de notice : A2016--071 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1515/geo-2016-0040 En ligne : https://doi.org/10.1515/geo-2016-0040 Format de la ressource électronique : URL article Permalink :
in Open geosciences > vol 8 n° 1 (January - July 2016) . - pp 493 - 502[article]A novel method to correct for wood MOE ultrasonics and NIRS measurements on increment cores in Liquidambar styraciflua L / Herizo Rakotovololonalimanana in Annals of Forest Science [en ligne], vol 72 n° 6 (September 2015)
Titre : A novel method to correct for wood MOE ultrasonics and NIRS measurements on increment cores in Liquidambar styraciflua L Type de document : Article/Communication Auteurs : Herizo Rakotovololonalimanana, Auteur ; Gilles Chaix, Auteur ; Loïc Brancheriau, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 753 - 761 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse comparative
[Termes IGN] élasticité
[Termes IGN] image proche infrarouge
[Termes IGN] Liquidambar styraciflua
[Termes IGN] spectrométrie
[Termes IGN] télédétection acoustique
[Termes IGN] ultrason
Résumé : (auteur) Key message : Ultrasounds overestimate the MOE value. This paper analyses the causes of this difference and opens the perspective for a novel method allowing the calculation of the correct MOE from ultrasounds or NIRS measurements on cores.
Context : Standardized methods for determining wood modulus of elasticity (MOE) are destructive and require many replicates. Other methods such as NIRS and ultrasound have been developed to characterize wood properties and overcome these constraints.
Aim : The aim of this study was to compare the two MOE measurement methods (NIRS and ultrasound) applied to cores of wood taken from standing trees (Liquidambar styraciflua).
Methods : MOE, measured by an acoustic method in standard samples (360 × 20 × 20 mm), was used as a reference. Then MOE was predicted by an NIRS model and determined using ultrasound in standard samples (360 × 20 × 20 mm), small samples (10 × 20 × 20 mm), and cores (15 mm in diameter).
Result : MOE values determined by acoustic method on standard samples and by ultrasonic method on small samples were correlated (R 2 = 0.72) and were not statistically different. The NIRS PLS regression yielded a model with R 2 cv = 0.80. The link between NIRS and ultrasound on cores was statistically significant (R 2 = 0.68).
Conclusion : The ultrasonic technique determines an apparent modulus enables comparative data analysis. This apparent modulus can be used for quantitative analysis if a corrective model is used. A correction formula to ultrasonic MOE was proposed in the case of a prismatic geometry.
Numéro de notice : A2015-409 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1007/s13595-015-0469-6 Date de publication en ligne : 12/03/2015 En ligne : https://doi.org/10.1007/s13595-015-0469-6 Format de la ressource électronique : URL article Permalink :
in Annals of Forest Science [en ligne] > vol 72 n° 6 (September 2015) . - pp 753 - 761[article]Atmospheric water vapour sensing by means of differntial absorption spectrometry using solar and lunar radiation / Stefan Walter Münch (2014)
Titre : Atmospheric water vapour sensing by means of differntial absorption spectrometry using solar and lunar radiation Type de document : Thèse/HDR Auteurs : Stefan Walter Münch, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2014 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 92 Importance : 210 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-35-2 Note générale : bibliographie, thèse publiée
Diss., Eidgenössische Technische Hochschule ETH Zürich, Nr. 21491, 2013
Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Atmosphère
[Termes IGN] correction troposphérique
[Termes IGN] détecteur à transfert de charge
[Termes IGN] pouvoir de résolution spectrale
[Termes IGN] rayonnement solaire
[Termes IGN] spectromètre
[Termes IGN] spectrométrie
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] troposphère
Index. décimale : 47.50 Atmosphère Résumé : (auteur) Tropospheric water vapour plays a crucial role in the understanding of a variety of different atmospheric processes, ranging from local weather phenomena to global climate change. Regarding satellite geodesy, water vapour acts as disturbing factor for various measurement methods, causing path delays of radio signals and consequently leads to considerable biases in the measurement results. The spatial and temporal concentration distribution can hardly be modelled and therefore has to be determined instrumentally to correct the influence computationally. The application of the principle of “Differential Optical Absorption Spectroscopy” (DOAS) using the sun as radiation source to locally determine integrated water vapour concentrations (PW), has proven itself as a very potent methodology, with good relative and absolute accuracy, high temporal resolution and comparably low calibration efforts. It also seems especially well suited for validation purposes for independent measurement methods.
The intention of the presented project is to implement the findings from the development of earlier prototype instruments and to contemplate several further aspects related with the DOAS approach to determine atmospheric water vapour: Improved temporal coverage of the measurement method through inclusion of night time measurements with the help of moonlight, which are enabled by means of a massively increased system sensitivity to deal with the up to six orders of magnitude lower intensity of the background radiation with respect to solar measurements. Further it is to investigate, how reliable acquisitions of sun transmission spectra can be achieved, when deploying the system on moving platforms, for possible future validation measurements of satellite-borne radiometer data on satellite ground tracks on the open sea. The prototype instruments developed should particularly feature high field versatility, requiring eased transportability, resistance to weather and not least the possibility of a fully automatic measurement procedure, including instrument self-calibration.
For this purpose two identically constructed compact measurement systems were built. The instruments dispose of a custom-built telescope (heliostat principle) and an optically directly coupled spectrometer unit. The whole system is enclosed in a rugged aluminium hull, including most of the steering electronics. The motorized telescope is able to follow the moving light source fully autonomously, also with the platform moderately moving. A quasi-monochromator with an echelle grating as main dispersion element is used as spectrometer unit, allowing a compact architecture, a great spectral resolution and efficiency at the same time. Together with a back-thinned CCD detector highly resolved images of water vapour absorption lines can be obtained. The primary wavelength range lies between 789 nm and 802 nm, the reciprocal linear dispersion amounts to 7.3 pm/px at a focal length of just 400 mm. A motorized deflection mirror in the spectrometer allows the observation of adjacent spectral windows and serves for the highly precise position stabilization of the spectrum on the CCD sensor.
Test measurements with the sun and the moon as background radiation source show the extraordinarily high system light throughput and the high spectral resolving power of the apparatus. However illumination dependent interference structures on the detector (etaloning) prevent the deduction of usable transmission spectra from the measured raw data. For that reason a variety of optical measures to homogenize the radiation entering the spectrometer with respect to field and aperture are examined. As a feasible solution, with sufficient radiation distribution and a still acceptable intensity attenuation, a short quartz light guiding fibre with a hexagonal cross section has been found and implemented.
For instrumental control a software package has been developed, which autonomously handles the measurement process including the various calibration processes and the interaction of the various sensors and actuators. Additionally a variety of algorithms have been provided, helping to eliminate various defective influences in the raw data, as the correction of stray and false light portions or the elimination of interspersed beat structures in lunar spectra. Furthermore procedures which serve in spectrum processing have been supplied, as for the computation of a holistic intensity baseline or the dynamic determination of apparatus profiles. For the determination of the water vapour concentrations from the measured spectroscopic data established computational procedures could be used mostly.
Various available spectroscopic databases have been analysed regarding the suitability of the listed absorption line parameters for the deduction of reliable water vapour concentrations. Comparison between the two identically built solar spectrometers yield considerable deviations of up to 1.5 kg/m 2 in the zenith integral concentrations which are presumably ascribable to systematic influences likely caused by unrecognized stray light influence. The mean value of the stochastic deviations amounts to about 1.1 % of the slant PW concentration. The cross-comparison with an independent measurement method, in this case GPS meteorology, however also shows significant divergences and thus point to the various further systematic effects which have to be examined more closely, as e.g. the uncertainty of the published spectroscopic parameters regarding line strength and line broadening as well as the baseline determination in the measured spectra.
Despite the considerable sensitivity losses with respect to the originally planned design due to beam homogenization, the methodology has been successfully applied to lunar measurements, albeit with reduced accuracy as stated in stochastic appraisals and with considerably lower temporal resolution.
The project presented here confirms and clarifies the possibilities of the application of DOAS for ground- based remote sensing of integral water vapour concentrations, but also gives clear indication on the different systematic biases which have to be examined more closely, e.g. regarding the accuracy of the spectroscopic parameters (both, for line strength and line broadening), as well as the determination procedure of the baseline in the measured spectra. This work also points out the chances as well as the serious difficulties which arise from the design, construction and deployment of highly integrated DOAS spectrometers of high performance. Regarding the application of various optical components and detectors for the development of similar instruments valuable insights have been gathered.
Numéro de notice : 14913 Affiliation des auteurs : non IGN Autre URL associée : URL ETH Zurich Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Sciences : ETH Zurich : 2013 DOI : 10.3929/ethz-a-010006561 En ligne : http://e-collection.library.ethz.ch/view/eth:7591 Format de la ressource électronique : URL Permalink :
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