Dg. Gu et al., A statistical approach for topographic correction of satellite images by using spatial context information, IEEE GEOSCI, 37(1), 1999, pp. 236-246
Citations number
18
Categorie Soggetti
Eletrical & Eletronics Engineeing
Journal title
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
The geometric and systematic errors associated with the acquisition and cor
egistration of a satellite image and digital terrain model (DTM) will signi
ficantly affect the results of topographic corrections, The conventional pi
xel-based topographic correction methods have not handled these errors well
. The corrected images, although exhibiting no significant residual topogra
phy in average, usually show high and nonhomogenous variability across the
scene. In this paper, me propose a contextual approach for minimizing this
artifactual and undesirable feature in the corrected images. The new approa
ch compensates the topographic shading and shadowing by using the local ref
lectance estimated from the spatial contexts. Since the noises have much le
ss effects on the extracted contextual information, errors are reduced for
the estimated reflectance and the signal-to-noise ratios are improved on th
e shaded slopes. As a result, not only is the variance lower and spatially
more homogenous, the fine textures and community boundaries are also well p
reserved on the corrected images. For the purpose of image interpretation,
the reduced variability for each cover type may lead to significant improve
ments of land cover differentiation, In the testing site of a forested scen
e, for example, the overall classification accuracy has improved about 9% i
n the contextually corrected image over the conventionally corrected images
.