FREE ELECTRONIC LIBRARY - Theses, dissertations, documentation

Pages:     | 1 ||

«Year: 1998 Endmember selection procedures for partial spectral unmixing of DAIS 7915 imaging spectrometer data in highly vegetated Areas Kneubühler, ...»

-- [ Page 2 ] --

Values lower than 0 are excluded as well. These endmembers are used in a second unmixing step. This process can be repeated until a certain “purity-criteria” like no negative abundances or all abundances between 0 and 1 is achieved. Fig. 6 shows the differences between a one-step spectral unmixing of sugar beet and a two-step unmixing based on iteratively determined purer endmembers from imaging data.

FIGURE 6: One-step (left) and two-step (right) spectral unmixing of sugar beet, based on image derived endmembers The evaluated methods indicate that ground truth collection is important to validate the different approaches of endmember selection. Correlating field measurements of biochemical and biophysical parameters to imaging data can offer the possibility to retrieve such parameters from imaging data. The approach using in-situ reference measurements of endmember spectra and the modelling approach using a SVAT Model may be more promising since image derived endmembers are made up of a spectral mixture of contributing elements, unless pure pixels are iteratively determined.

Nevertheless, it remains difficult to define representative endmember spectra. Modelling endmember spectra bases on the availability of a range of parameters describing the status of the plant and the architecture of the canopy, which itself is subject to strong BRDF effects. Applications in vegetation studies have to take into account these effects, since airborne imaging spectrometers with large swath angles produce data of high geometric complexity.

4 REFERENCES [1] OERTEL, D., 1994: “The High Resolution Imaging Spectrometer DAIS: a Status Report”, in: 2nd EARSEC Status Seminar, ed. A.J. Sieber, JRC Ispra [2] SCHAEPMAN, M., KNEUBUEHLER, M., MEIER, E., MUELLER,SCHLÄPFER, D., STROBL, P., REULKE, R. AND HORN, R., 1998: “Fusion of Hyperspectral (DAIS 7915), Wide-angle (WAAC), and SAR (E-SAR) Data Acquisition Methods - The MultiSwiss’97 Campaign”, Proc. SPIE, 3438 [3] SCHAEPMAN, M., 1998: “Calibration of a Field Spectroradiometer - Calibration and Characterization of a Non-Imaging Field Spectroradiometer Supporting Imaging Spectrometer Validation and Hyperspectral Sensor Modelling”, PhD thesis, Dept. of Geography, Univ. of Zurich, p.146 [4] RICHTER, R., 1996: “Atmospheric correction of DAIS hyperspectral image data”, Computers and Geosciences, 22: 785-793 [5] SCHLÄPFER, D.R., 1998: “Differential Absorption Methodology for Imaging Spectroscopy of Atmospheric Water Vapor”, PhD thesis, Dept. of Geography, Univ. of Zurich, p. 131 [6] ENDSLEY, N. H., 1995: “Spectral unmixing algorithms based on statistical models”, Proc. SPIE, 2480: 23-36 [7] VERDEBOUT, J., JACQUEMOUD, S. AND SCHMUCK, G., 1994: “Optical properties of leaves: modelling and experimental studies”, in: Imaging Spectroscopy - a Tool for Environmental Obs., eds. Hill, J. and Mégier, J., Euro Courses, Kluwer, 4: 169-191 [8] JACQUEMOUD, S. AND BARET, F.,1990: “PROSPECT: a model of leaf optical properties spectra”, Rem. Sens. Env. 34: 75-91 [9] VERHOEF, W., 1984: “Light scattering by leaf layers with application to canopy reflectance modelling: the SAIL model”, Rem. Sens. Env. 16: 125-141 [10] CLEVERS, J.G.P.W., 1994: “Imaging spectrometry in agriculture - plant vitality and yield indicators”, in: Imaging Spectroscopy - a Tool for Environmental Obs., eds. Hill, J.

and Mégier, J., Euro Courses, Kluwer, 4: 193-219 [11] SCHLÄPFER, D., MEYER P. AND ITTEN, K.I., 1998: “Parametric Geocoding of AVIRIS Data Using a Ground Control Point Derived Flightpath”, Summaries of the Seventh JPL Airborne Earth Science Workshop, (in press), JPL, Pasadena (CA), pp. 6 [12] BOARDMAN, J.W., 1990: “Inversion of high spectral resolution data”, Proc. SPIE, 1298: 222-233 [13] RSI Inc., 1997: “ENVI User’s Manual”, Vers. 3.0, Lafayette [14] SCHANZER, D.L., 1993: “Comments on ‘The Least Squares Mixing Models to Generate Fraction Images Derived for Remote Sensing Multispectral Data’“, TGARS, 31: 747

Pages:     | 1 ||

Similar works:

«A Guide for Farmers on Good Land Husbandry Draught Animal Harnessing Draught Animal Harnessing -1Draught Animal Harnessing -2ACKNOWLEDGEMENTS This guide results from a collaborative effort based on the work and contributions from the following institutions and individuals: Zimbabwe Farmers Union (ZFU) : Mrs V. Mandishona (Chief Education and Training Officer); Mr P. Zakariya (Training Officer); Mr J. Chimwanda (Masvingo Provincial Farmer Organiser); Mr P. Mushure (Masvingo ZFU Provincial...»

«Managing Dairy Manure in the Central Valley of California University of California Division of Agriculture and Natural Resources Committee of Experts on Dairy Manure Management September 2003 February 2004, Revised July 2004, Revised June 2005, Revised University of California Division of Agricultural and Natural Resources Committee of Experts on Dairy Manure Management Andrew Chang, Professor and Associate Director Center for Water Resources, University of California Thomas Harter, Associate...»

«Agrodok-series No. 14 Dairy cattle husbandry Agrodok 14 Dairy cattle husbandry More milk through better management Agrodok 14 Dairy cattle husbandry More milk through better management Hans Blauw Gijs den Hertog Johan Koeslag This publication is sponsored by: Heifer International © Agromisa Foundation and CTA, Wageningen, 2008. All rights reserved. No part of this book may be reproduced in any form, by print, photocopy, microfilm or any other means, without written permission from the...»

«DAIRY FARMING IN SOUTH AFRICA – WHERE TO NOW? William Gertenbach Institute for Animal Production Western Cape Departement of Agriculture INTRODUCTION The dominant variable in livestock farming is the supply of feed and water for the animals. It follows that environmental factors, which includes temperature, rainfall (quantity and distribution), sun hours and soil types, play a significant role in livestock farming. In dairy farming, because fresh milk is a relatively perishable product,...»

«Dairy Birthe Lassen Dairy production in South Africa impressions Country Report 2012/1 Dairy Production in South Africa – impressions Acknowledgements My thanks go to the European Dairy Farmers who co-financed the journey to South Africa and the participation at the World Dairy Summit (IDF 2012) in Cape Town. Birthe J. Lassen Dairy farming in a free market: Impressions from South Africa For the quick reader: 2,6 billion kg of milk per year/2,300 dairy farmers/average herd size: 300 cows per...»

«Sundaresan School of Animal Husbandry and Dairying SAM HIGGINBOTTOM INSTITUTE OF AGRICULTURE, TECHNOLOGY & SCIENCES (Formerly Allahabad Agriculture Institute) (Deemed to-be-University) Allahabad – 211007 Course Structure of B.Sc. Animal Husbandry & Dairying [now B.Sc. (H) Dairying] SEMESTERI Course code Course title L-T-P Credits CSIT 301 Introduction to Computer Application 2-0-2 3 MAS 303 Elementary Mathematics-I 2-0-0 2 LNG 300 English and Basic Technical writing 3-0-0 3 MBFT 349...»

<<  HOME   |    CONTACTS
2016 www.theses.xlibx.info - Theses, dissertations, documentation

Materials of this site are available for review, all rights belong to their respective owners.
If you do not agree with the fact that your material is placed on this site, please, email us, we will within 1-2 business days delete him.