In comparison with the sole use of L-
bination of C- and L-band data also redu
between bare/sparsely vegetated land and crop/rangeland by
88.98% (Figure 10). Compared with the L-band image, the
ed the volume scattering difference be-
and bare/sparsely vegetated land by as
much as 120.80% (Figure 13). The C-band radar is less pen-
etrating than the L-band radar because it has a shorter wave-
length (Lang
et al.
2008). Given the difference in the pen-
etrating capability, the C-band radar tended to interact with
vegetation, whereas the L-band radar was prone to penetrate
vegetation. As a result, the C-band image was more sensitive
to vegetation and created a more remarkable difference in
volume scattering between crop/rangeland and bare/sparsely
vegetated land than the L-band image. Therefore, the addition
of C-band data was beneficial for distinguishing bare/sparsely
vegetated land and crop/rangeland (Figure 6b).
Additionally, the combination of C- band L-band data
reduced the confusion between built-up areas and forests by
81.44% compared with the sole use of L-band data (Figure
10). The user’s and producer’s accuracies of built-up areas
improved by 3.13% and 1.84% due to the addition of C-band
data, respectively. The C-band image increased the double-
bounce scattering difference between forests and built-up
areas by as much as 214.43% compared with the L-band
image (Figure 14). Built-up areas featured a stronger double-
bounce scattering than forests in both images. The C-band
SAR
interacted mainly with the canopy layer of forests and
had difficulty in reaching the trunks and soil because it
Figure 8. Overall accuracies and kappa values obtained using the different combinations of TerraSAR-X, RADARSAT-2, and
PALSAR images for land cover classification.
Figure 9. Producer’s and user’s accuracy o
eir combination for each land cover class.
Figure 10. Comparison of land cover classification
confusion yielded by the L-band image, C-band image, and
their combination.
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
November 2019
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