DocumentCode :
1159082
Title :
An Analysis of Angle-Based With Ratio-Based Vegetation Indices
Author :
Jiang, Zhangyan ; Huete, Alfredo R. ; Li, Jing ; Chen, Yunhao
Author_Institution :
Coll. of Resources Sci. & Technol., Beijing Normal Univ.
Volume :
44
Issue :
9
fYear :
2006
Firstpage :
2506
Lastpage :
2513
Abstract :
Remotely sensed, angle-based vegetation indices that measure vegetation amounts by the angle between an approximated soil line and a simulated vegetation isoline in the red-near-infrared reflectance space were developed and evaluated in this paper. Unsalan and Boyer previously proposed an angle-based vegetation index, thetas (denoted as thetas NDVI in this paper), based on the normalized difference vegetation index (NDVI) with the objective of overcoming the saturation problem in the NDVI. However, thetasNDVI did not consider strong soil background influences present in the NDVI. To reduce soil background noise, an angle-based vegetation index, thetasSAVI , based on the soil-adjusted vegetation index (SAVI), was derived using trigonometric analysis. The performance of thetasNDVI and thetasSAVI was evaluated and compared with their corresponding vegetation indices, NDVI and SAVI. The soil background influence on thetasNDVI was found to be as significant as that on the NDVI. thetasNDVI was found to be more sensitive to vegetation amount than the NDVI at low vegetation density levels, but less sensitive to vegetation fraction at high vegetation density levels. Thus, the saturation effect at high vegetation density levels encountered in the NDVI was not mitigated by thetasNDVI. By contrast, thetasSAVI exhibited insignificant soil background effects and weaker saturation, as in SAVI, but also improved upon the dynamic range of SAVI. Analyses and evaluation suggest that thetasSAVI is an optimal vegetation index to assess and monitor vegetation cover across the entire range of vegetation fraction density levels and over a wide variety of soil backgrounds
Keywords :
soil; vegetation; vegetation mapping; NDVI; SAVI; angle-based vegetation index; normalized difference vegetation index; ratio-based vegetation index; red-near-infrared reflectance; remotely sensing; saturation effect; soil background effect; soil line; soil-adjusted vegetation index; vegetation fraction density; vegetation isoline; Background noise; Contamination; Dynamic range; Extraterrestrial measurements; MODIS; Monitoring; Radiometry; Reflectivity; Soil measurements; Vegetation mapping; angle-based vegetation indices; saturation effect; soil background effects;
fLanguage :
English
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
Publisher :
ieee
ISSN :
0196-2892
Type :
jour
DOI :
10.1109/TGRS.2006.873205
Filename :
1677760
Link To Document :
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