Image Processing Reference
Fig. 4.2 Examples of urban spectra derived from two different sources: ground spectrometry
( diagrams in the upper left and middle right ) and hyperspectral image data ( diagram in the
lower left ). The major water absorption bands (1,340-1,480 and 1,770-1,970 nm) are linearly
measurements describes the bi-directional reflectance factor, also referred to as the
reflectance of the sample surface expressed in percent. Hyperspectral remote sensing
measurements (in radiance) have to be converted to reflectance values by correcting
for atmospheric influences and wavelength-dependent changes in solar irradiance.
This process can be quite challenging and is one of the main reasons why image
spectra are in general noisier than ground measurements.