
9
Change Detection
To quote a well-known, if now rather dated, review a rticle on change detection
(Singh, 19 89),
The basic premise in using remote sensing data for change de-
tection is that chang es in land cover must result in changes in
radiance values ... [which] must be larg e with respect to radiance
changes from other factors.
When comparing multispectral images of a given scene taken at different
times, it is there fore desirable to correct the pixel intensities as much as pos-
sible for uninteresting differences s uch as those due to solar illumination, at-
mospheric conditions or sensor calibration. In the case of SAR imagery, sola r
illumination ...