Title :
Measurements on individual trees using multiple VHF SAR images
Author :
Hallberg, B. ; Smith-Jonforsen, G. ; Ulander, L.M.H.
Author_Institution :
Dept. of Radio & Space Sci., Chalmers Univ. of Technol., Goteborg, Sweden
Abstract :
Multiple VHF-band radar images from the airborne CARABAS-II system, retrieved with varying look direction to the imaged area, are coregistered and combined to improve spatial and radiometric resolution. Combined images over boreal forest in southern Sweden are used to identify and make backscatter measurements of individual trees. A coregistration scheme is proposed, and backscatter is compared to ground measurements of individual stem volume. It is found that the spatial resolution and radiometric precision could be significantly improved by combining the images coherently. A nearly linear relation between backscattered amplitude and individual stem volume for trees with a stem volume over 0.2 m3 was found, which is in agreement with previous results at stand level.
Keywords :
backscatter; forestry; radar imaging; radiometers; remote sensing by radar; synthetic aperture radar; vegetation mapping; airborne CARABAS-II system; backscatter measurements; forest biomass; image matching; multiple VHF SAR images; radiometry; scattering model; southern Sweden; synthetic aperture radar; tree stem volume; very high frequency radar; Backscatter; Frequency; Infrared sensors; Laser radar; Optical scattering; Optical sensors; Space technology; Synthetic aperture radar; Terrain mapping; Vegetation mapping; Forest biomass; image matching; scattering model; stem volume; synthetic aperture radar (SAR); very high frequency (VHF);
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
DOI :
10.1109/TGRS.2005.855622
