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Multiangular crop differentiation and LAI estimation using PROSAIL model inversionMazumdar, Deepayan Dutta January 2011 (has links)
Understanding variations in remote sensing data with illumination and sensor angle changes is important in agricultural crop monitoring. This research investigated field bidirectional reflectance factor (BRF) in crop differentiation and PROSAIL leaf area index (LAI) estimation. BRF and LAI data were collected for planophile and erectophile crops at three growth stages. In the solar principal plane, BRF differed optimally at 860 nm 60 days after planting (DAP) for canola and pea, at 860 nm 45 and 60 DAP for wheat and barley, and at 860 nm and 670 nm 45 and 60 DAP for planophiles versus erectophiles. The field BRF data helped better understand PROSAIL LAI estimation. NDVI was preferred for estimating LAI, however the MTVI2 vegetation index showed high sensitivity to view angles, particularly for erectophiles. The hotspot was important for crop differentiation and LAI. Availability of more along-track, off-nadir looking spaceborne sensors was recommended for agricultural crop monitoring. / xiii, 161 leaves : ill., map ; 29 cm
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Spectroscopic study of channel spectra phenomena in the synchrotron-based FTIR spectrometer at the Canadian Light SourceIbrahim, Amr, University of Lethbridge. Faculty of Arts and Science January 2010 (has links)
Recently, the high radiance of synchrotron sources was used to enhance FTIR
spectrometer performance. However, excessive channel spectra when synchrotron
sources are used degrade the quality of retrieved spectral parameters. In the
research reported in this thesis, seven different techniques for handling channel
spectra were investigated. These techniques were used to reduce channel spectra
for a test group of seven samples of CO2 mixed with air recorded using the
synchrotron source at the Canadian Light Source. The increases in signal to noise
ratio (SNR) of spectra handled with each technique were calculated. SNR results
showed that transmission spectra, produced using synthetic background spectra
with simulated channel spectra, achieved the highest SNR improvement. However,
when the spectra groups were fitted using nonlinear least square fit algorithm, the
technique using channel spectra fitting produced the smallest fitting residual.
Moreover, the retrieved intensities and air broadening coefficients of 21 spectral
lines showed that the spectral fitting technique produced the most accurate values
as compared to the HITRAN 2008 database. Although the spectral fitting technique
was accurate in retrieving spectral line parameters, applying the technique at wider
spectral ranges was less accurate.
A modification to the channel spectra fitting technique by performing
iterations of channel fitting was introduced to process wider spectral ranges.
Carbon dioxide laser band I centred at 961 wavenumber was analyzed using 24
spectra recorded under different experimental conditions. The intensity and air-and self-broadening coefficients were retrieved for 48 spectral lines with average
deviations from HITRAN database values of 2.11%, 1.25% and 4.14%, respectively,
using the Voigt profile. These average deviations lie within the uncertainty limits
listed by the database. The deviation between our results and other results reported
in the literature were also examined and it is found to be also within the range of
HITRAN uncertainties. The effect of errors in fitting channel spectra parameters was
examined and found to be mitigated by the inclusion of channel-free spectra in the
multispectral fit. / xiv, 134 leaves : ill. ; 29 cm
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