Title :
Derivative analysis for in situ high dynamic range hemispherical photography and its application in forest stands
Author :
Jonckheere, Inge G C ; Muys, Bart ; Coppin, Pol R.
Author_Institution :
Dept. of Land Manage., Katholieke Univ. Leuven, Belgium
fDate :
7/1/2005 12:00:00 AM
Abstract :
A new methodology is presented to threshold high dynamic range hemispherical color photographs of forest canopies. It is based on the second derivative of brightness profiles along circular transects over the whole azimuthal range of angles at narrow annulus zenith rings. A fast, reliable, and objective way of extracting canopy forest parameters is described and illustrated for calculation of the monodirectional gap fraction around the zenith angle of 57.3°, which is independent on average leaf angle distribution.
Keywords :
colour photography; vegetation mapping; brightness profiles; circular transects; color photographs; forest canopies; forest parameters extraction; forest stands; high dynamic range hemispherical photography; leaf angle distribution; methodology; monodirectional gap fraction; zenith angle; Aggregates; Biomass; Brightness; Cameras; Dynamic range; Helium; Optical attenuators; Photography; Remote monitoring; Vegetation mapping; Canopy parameters; derivative analysis; high dynamic range hemispherical photography; thresholding;
Journal_Title :
Geoscience and Remote Sensing Letters, IEEE
DOI :
10.1109/LGRS.2005.846904
