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Estimation of 3D vegetation structure from waveform and discrete return airborne laser scanning data

Lindberg, Eva and Olofsson, Kenneth and Holmgren, Johan and Olsson, Håkan (2012). Estimation of 3D vegetation structure from waveform and discrete return airborne laser scanning data. Remote sensing of environment. 118:March, 151-161
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Official URL: http://dx.doi.org/10.1016/j.rse.2011.11.015

Abstract

This study presents and compares new methods to describe the 3D canopy structure with Airborne Laser Scanning (ALS) waveform data as well as ALS point data. The ALS waveform data were analyzed in three different ways; by summing the intensity of the waveforms in height intervals (a); by first normalizing the waveforms with an algorithm based on Beer-Lambert law to compensate for the shielding effect of higher vegetation layers on reflection from lower layers and then summing the intensity (b); and by deriving points from the waveforms (c). As a comparison, conventional, discrete return ALS point data from the laser scanning system were also analyzed (d). The study area was located in hemi-boreal, spruce dominated forest in the southwest of Sweden (Lat. 58° N, Long. 13° E). The vegetation volume profile was defined as the volume of all tree crowns and shrubs in 1 dm height intervals in a field plot and the total vegetation volume as the sum of the vegetation volume profile in the field plot. The total vegetation volume was estimated for 68 field plots with 12 m radius from the proportion between the amount of ALS reflections from the vegetation and the total amount of ALS reflections based on Beer-Lambert law. ALS profiles were derived from the distribution of the ALS data above the ground in 1 dm height intervals. The ALS profiles were rescaled using the estimated total vegetation volume to derive the amount of vegetation at different heights above the ground. The root mean square error (RMSE) for cross validated regression estimates of the total vegetation volume was 31.9% for ALS waveform data (a), 27.6% for normalized waveform data (b), 29.1% for point data derived from the ALS waveforms (c), and 36.5% for ALS point data from the laser scanning system (d). The correspondence between the estimated vegetation volume profiles was also best for the normalized waveform data and the point data derived from the ALS waveforms and worst for ALS point data from the laser scanning system as demonstrated by the Reynolds error index. The results suggest that ALS waveform data describe the volumetric aspects of vertical vegetation structure somewhat more accurately than ALS point data from the laser scanning system and that compensation for the shielding effect of higher vegetation layers is useful. The new methods for estimation of vegetation volume profiles from ALS data could be used in the future to derive 3D models of the vegetation structure in large areas.

Authors/Creators:Lindberg, Eva and Olofsson, Kenneth and Holmgren, Johan and Olsson, Håkan
Title:Estimation of 3D vegetation structure from waveform and discrete return airborne laser scanning data
Series/Journal:Remote sensing of environment (0034-4257)
Year of publishing :15 March 2012
Volume:118
Number:March
Page range:151-161
Publisher:Elsevier
ISSN:0034-4257
Language:English
Publication Type:Journal article
Refereed:Yes
Article category:Scientific peer reviewed
Version:Accepted version
Full Text Status:Public
Agris subject categories.:K Forestry > K10 Forestry production
U Auxiliary disciplines > U40 Surveying methods
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Keywords:LiDAR, Waveform, Canopy structure, Vegetation profiles
URN:NBN:urn:nbn:se:slu:epsilon-e-758
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-758
Additional ID:
Type of IDID
DOI10.1016/j.rse.2011.11.015
ID Code:9281
Department:(S) > Dept. of Forest Resource Management
(NL, NJ) > Dept. of Forest Resource Management
External funders:Hildur och Sven Wingquists stiftelse för skogsvetenskaplig forskning and Swedish Environmental Protection Agency
Deposited By: Skogsbiblioteket Umeå
Deposited On:06 Dec 2012 14:22
Metadata Last Modified:02 Dec 2014 10:53

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