T. Wassenaar et al., Sunlit soil surface extraction from remotely sensed imagery of perennial, discontinuous crop areas; the case of Mediterranean vineyards, AGRONOMIE, 21(3), 2001, pp. 235-245
In the Mediterranean wine producing region, soil surface remote sensing for
hydrological modelling is hampered by the discontinuous canopy of the pere
nnial vine stocks. Very high spatial resolution imagery allows the recordin
g of ground resolution elements that comprise only soil in between vine sto
cks. To enable the comparison of the resolution element's spectral properti
es with known bi-directional properties of different types of soil surface,
pixels representing the pure and sunlit soil surface have first to be extr
acted from the imagery. Multi-scale analysis proved to provide a robust and
satisfactory segmentation method. Conditional per-field adjustment of a mu
lti-scale image mask allows the extraction of the image segments correspond
ing to the sunlit soil surface, whatever its state or composition. Moreover
, the vegetation cover can be estimated with an error of at most 10% if the
geometric configuration is taken into account.