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Gaussian Decomposition of Laser Altimeter WaveformsWe develop a method to decompose a laser altimeter return waveform into its Gaussian components assuming that the position of each Gaussian within the waveform can be used to calculate the mean elevation of a specific reflecting surface within the laser footprint. We estimate the number of Gaussian components from the number of inflection points of a smoothed copy of the laser waveform, and obtain initial estimates of the Gaussian half-widths and positions from the positions of its consecutive inflection points. Initial amplitude estimates are obtained using a non-negative least-squares method. To reduce the likelihood of fitting the background noise within the waveform and to minimize the number of Gaussians needed in the approximation, we rank the "importance" of each Gaussian in the decomposition using its initial half-width and amplitude estimates. The initial parameter estimates of all Gaussians ranked "important" are optimized using the Levenburg-Marquardt method. If the sum of the Gaussians does not approximate the return waveform to a prescribed accuracy, then additional Gaussians are included in the optimization procedure. The Gaussian decomposition method is demonstrated on data collected by the airborne Laser Vegetation Imaging Sensor (LVIS) in October 1997 over the Sequoia National Forest, California.
Document ID
20000075549
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Hofton, Michelle A.
(Maryland Univ. College Park, MD United States)
Minster, J. Bernard
(Scripps Institution of Oceanography La Jolla, CA United States)
Blair, J. Bryan
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
September 7, 2013
Publication Date
August 23, 1999
Subject Category
Lasers And Masers
Funding Number(s)
CONTRACT_GRANT: NAG5-3001
CONTRACT_GRANT: NAS5-33019
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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