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Fundamentals of Remote Sensing

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1. Much the same as with optical sensors that have different bands or channels of data, multi-wavelength and multi-frequency radar images can provide complementary information. Radar data collected at different wavelengths is analogous to the different bands of data in optical remote sensing. Similarly, the various polarizations may also be considered as different bands of information. Depending on the wavelength and polarization of the radar energy, it will interact differently with features on the surface. As with multi-band optical data, we can combine these different "channels" of data together to produce colour images which may highlight subtle variations in features as a function of wavelength or polarization.
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2. A scatterometer is used to precisely measure the intensity of backscatter reflected from an object or surface. By accurately characterizing (i.e. measuring) the intensity of energy reflected from a variety of objects or surface types, these measurements can be used to generate typical backscatter signatures, similar to the concept of spectral signatures with optical data. These measurements can be used as references for calibrating imagery from an imaging radar sensor so that more accurate comparisons can be made of the response between different features.

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