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TitleDetermining the Contribution of Shaded Elements of a Canopy to Remotely Sensed Hyperspectral Signatures
DownloadDownloads (Preprint)
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorWhite, H PORCID logo; Sun, L; Staenz, K; Fernandes, R AORCID logo; Champagne, C
SourceProceedings of the 1st International Symposium on Recent Advances on Quantitative Remote Sensing, Torrent, Valencia (Spain), 16-20 September; 2002., Open Access logo Open Access
Alt SeriesEarth Sciences Sector, Contribution Series 20043159
Mediapaper; on-line; digital
File formatpdf
Released2002 01 01
AbstractHyperspectral imagery has the potential to become a useful tool for monitoring and extracting biophysical properties of vegetated areas. Exploitation of this potential relies on the ability to relate at-canopy spectral reflectance to biophysical characteristics of vegetation and derive both sunlit and shaded component proportions and spectral profiles. Increased application of hyperspectral imagery to these areas is expected with the advent of space borne hyperspectral sensors (such as EO-1 Hyperion and CHRIS-PROBA). Such imagery of vegetated scenes is influenced however by the well known bidirectional reflectance distribution (BRDF) effect.

One method of determining the contribution of shaded overstorey vegetation and background to observed spectral reflectance is to determine, by model inversion, the proportion of shaded surfaces viewed by the sensor, and the relative intensity of the radiative flux incident on these surfaces. This can be achieved by modelling the overall reflectance as composed of mean sunlit and shaded reflectance components, combined with an analytical description of the shaded radiant flux. Assuming a land cover type with consistent mean foliage and background reflectance, inversion of a semi-empirical model can be used to determine BRDF coefficients, which can then be applied to normalize the imagery to a specific view/sun geometry. If the modelled spectral coefficients directly relate to canopy properties, then BRDF normalization can also provide information to help directly relate the canopy architectural and biophysical properties to the remotely sensed signal. One such model, FLAIR, has been successfully used to investigate canopy characteristics from airborne and satellite spectral imagery.


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