Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

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Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [THP-1 HIGH SPECTRAL RESOLUTION MEASUREMENT]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: Analysis of Airborne Imaging Spectrometer Data: FLI and AVIRIS Image Comparisons. J. R. Freemantle and J. R. Miller

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INTRODUCTION Myperspectral data presents interesting opportunities and challenges to researchers, not the least of which is the problems associated with displaying and manipulating imagery with over 200 channels and 16 bit resolution. The FLI has 288 spectral bands from 0.43 to 0.805 microns and the AVIR1S has 224 spectral channels from 0.4 to 2.5 microns. The AVIRIS data also can be obtained spectrally-resampled to 210 channels. Most commercial image processing packages do not support imaging spectrometery sensors at their full spectral and radiometeric resolution. At the Institute for Space and Terrestrial Science (ISTS) we have developed an Imaging Spectrometer Analysis Package for the quantitative analysis of full resolution imaging spectrometery data. This work grew from a cooperative project between York University and Moniteq Ltd. to study data from the Canadian Fluorescence Line Imager (FLI) (Miller et al., 1987). IMPLEMENTATION At ISTS, software has been written to analyze imaging spectrometer data from the FLI and from NASA’s Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) at full spectral, spatial and radiometeric resolution. The only limitation being the availability of disk space to store the very large volume of data: 16 MB for a typical FLI full spectral scene and 120 MB for a full AVIRIS scene. The image is usually subset to a more manageable size for analysis. The Imaging Spectrometer software is integrated into PCI’s EASI/PACE image analysis system using the Software Toolbox (PCI, 1989a). Imaging spectrometery data is stored consistent with the PCIDSK format (PCI, 1989b). Currently the software runs on a Microvax II, Sun workstation (SUN 3/60) and a PC based image processing workstation. A modular approach was taken to the software development. Instead of independent systems for batch and interactive processing of the imagery, one library of fundamental subroutines was used (see Figure 1) to which all modules are linked. In the interactive mode, FORTRAN modules were strung together by an EASI procedure (command file). This allows new analysis modules to be incorporated easily and permits each module to be run independently if the need arises. In the batch mode one large FORTRAN programme is used that does all the processing tasks. I'he first step in the analysis procedure, whether it be batch or interactive, is to select and calibrate the data. A tablet (or mouse) is used to define a window of interest from the displayed image for interactive processing. The average digital value for the window is calculated. For batch processing an image database input window is specified and calculations are done on a pixel by pixel basis. The data must be calibrated to appropriate units and for this purpose the software allows several options. Calibration files are stored for spectral, radiometric and reflectance calibration. Conversion to radiance is done using radiance scale factors supplied by the sensor’s manufacturer. One useful option is to employ a table of extra-terrestrial solar irradiance values and the image geometry to convert the image to pseudo-reflectance values. An approximate atmospheric correction procedure can be applied if ground measurements of suitable reflectance targets are supplied and a digital-number-to-reflectance calibration is available. If a Digital Terrain Model (DTM) is available a correction for topography can be made. The analyst determines which calibration procedure is to be used. Interpretation algorithms or inverse models can now be applied to calibrated data. These algorithms can extract spectral and/or reflectance parameters such as reflectance ratios, watercolour parameters (Freemantle and Miller, 1987) or vegetation red edge spectral parameters (Miller et al., 1990b). In the interactive mode the calculated parameters and spectral curves are displayed at the workstation terminal for the analyst to assess (see Figure 2). The EASI/PACE parameter file stores interpretation choices, for example the vegetation red edge spectral window, for use during batch processing of the image. During batch processing user selected calculated parameters are written back to a PCIDSK image database in 8 bit form. This image can be then analyzed using conventional methods such as thresholding, pseudo-colour, etc. The modular approach allows new interpretation, atmospheric correction or calibration models to be added to the software with a minimum of effort. APPLICATION The Imaging Spectrometery Analysis Package has been used to analyze AVIRIS and FLI data over vegetated targets (Miller et al. 1990, Rock et al., 1990). The red edge analysis can be applied to both the FLI and AVIRIS data (see

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