Centre de documentation
scientifique

A digital camera as a tool to measure colour indices and related properties of sandy soils in semi-arid environments / N. Levin in International Journal of Remote Sensing IJRS, vol 26 n° 24 (December 2005)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 26 n° 24 (December 2005) . - pp 5475 - 5492 Titre : A digital camera as a tool to measure colour indices and related properties of sandy soils in semi-arid environments Type de document : Article/Communication Auteurs : N. Levin, Auteur ; Eyal Ben-Dor, Auteur ; A. Singer, Auteur Année de publication : 2005 Article en page(s) : pp 5475 - 5492 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse comparative [Termes IGN] caméra numérique [Termes IGN] composition chimique [Termes IGN] couleur du sol [Termes IGN] étalonnage des données [Termes IGN] fer [Termes IGN] image RVB [Termes IGN] particule [Termes IGN] sable [Termes IGN] spectromètre [Termes IGN] zone semi-aride Résumé : (Auteur) Soil colour carries important information regarding the soil's chemical and physical properties. However, common practices for measuring soil colour, either by Munsell charts or by field/laboratory spectrometers, are insufficient, due to the subjective and nonquantitative character of the Munsell charts, and to the high cost and inconvenience of field spectrometers. We present herein, a method to characterize the colour of soil samples, and related chemical and physical properties of the soil, using a digital camera, and an array of coloured plastic chips, that are used for calibration purposes. Using 370 samples of sandy soils, we have demonstrated that both RGB values from digital images and their derived soil indices, correlate highly with similar measurements performed by a field spectrometer. When checked against free iron oxide content and against the percentage of fine particles in a subsample set of 42 soils, the redness index as measured by the digital camera gave similar or better correlations than those obtained from a field spectrometer, against both free iron oxides and fine particle contents (R2 of 89% for the iron oxides, and of for the fine particles). We propose the use of a digital camera as a field analytical tool to determine precisely: soil colour, iron oxide and fine particle content. Further study in this direction, with other soil population and more soil properties, is strongly advised in order to launch this as a vastly applicable and generic method. Numéro de notice : A2005-522 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160500099444 En ligne : https://doi.org/10.1080/01431160500099444 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27658 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-05241	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt

A ratio vegetation index adjusted for soil brightness / D.J. Major in International Journal of Remote Sensing IJRS, vol 11 n° 5 (May 1990)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 11 n° 5 (May 1990) . - pp 727 - 740 Titre : A ratio vegetation index adjusted for soil brightness Type de document : Article/Communication Auteurs : D.J. Major, Auteur ; F. Baret, Auteur ; Gérard Guyot, Auteur Année de publication : 1990 Article en page(s) : pp 727 - 740 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] couleur du sol [Termes IGN] humidité du sol [Termes IGN] indice de végétation [Termes IGN] luminance lumineuse [Termes IGN] rayonnement proche infrarouge [Termes IGN] réflectance du sol Résumé : (Auteur) Improved parameters for a soil-adjusted vegetation index (SAVI) are derived using SAIL model output for simulated wheat canopy reflectance. The SAVI is much less sensitive than the ratio vegetation index to changes in background caused by soil colour or surface soil moisture content. The parameters are developed to minimize variability due to soil brightness over the practical range of solar elevations, leaf angle distributions (LAD) and leaf area indices (LAI). The parameters are added to the near-infrared (NIR) and red reflectances before calculating the NIR/red ratio. Three new versions of the SAVI are developed based on the theoretical consideration of the effects of wet and dry soils. All three are superior to the NIR/red ratio, the perpendicular vegetation index and a soil-adjusted vegetation index. Our simplest version requires the addition of a parameter to the red reflectance. The second and third versions require an iterative procedure to find the best parameters that are then added to the red or the NIR and red reflectances. In general, SAVI adjustment parameters required to remove soil-brightness effects decrease as factors that obscure the soil-surface increase. Low solar elevation and high LAI result in increasingly negative values for the parameters. The NIR/red ratio is the vegetation index least influenced by soil brightness at LAI greater than three. Our iterated versions have lowest overall errors but are occasionally subject to higher errors at the combination of low zenith angles and erectophile canopies. The SAVI based on the bare soil reflectance performs best on field data. Numéro de notice : A1990-085 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431169008955053 En ligne : https://doi.org/10.1080/01431169008955053 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=25502 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-90051	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Munsell soil color and soil reflectance in the visible spectral bands of Landsat MSS and TM data / R. Escadafal in Remote sensing of environment, vol 27 n° 1 (01/01/1989)  

Public [article]  inRemote sensing of environment > vol 27 n° 1 (01/01/1989) . - pp 37 - 46 Titre : Munsell soil color and soil reflectance in the visible spectral bands of Landsat MSS and TM data Type de document : Article/Communication Auteurs : R. Escadafal, Auteur ; Michel-Claude Girard, Auteur ; Dominique Courault, Auteur Année de publication : 1989 Article en page(s) : pp 37 - 46 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] bande visible [Termes IGN] couleur du sol [Termes IGN] image Landsat-MSS [Termes IGN] image Landsat-TM [Termes IGN] réflectance du sol [Termes IGN] réflectance spectrale Numéro de notice : A1989-065 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/0034-4257(89)90035-7 En ligne : https://doi.org/10.1016/0034-4257(89)90035-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=25025 [article]