Radar Images Interpretation and Applications
Materials with a higher dielectric constant are excellent reflectors of the radar energy and absorb less energy, while the ones with a lower dielectric constant are excellent absorbers and reflect less energy. A smooth surface will tend to reflect microwave energy in one direction while a rough surface will scatter radiation in all directions. While analysing radar images, one must keep in mind the fact that, even if the image is presented as an analog product or photographic paper, the radar sees the scene in a different way from the human eye or from an optical sensor.
Concept of Interferometric Synthetic Aperture Radar
In SAR Interferometry, the satellite observes the same area from slightly different look-angles. This can be done either simultaneously (with two radars mounted on the same platform) or at different times by exploiting repeated orbits of the same satelliteThe two most important SAR Interferometry applications: Digital Elevation Model and Differential Interferometry. The essential parameters needed to get the best results from SAR interferometry analysis are: View angle, Geometrical baseline, Temporal Baseline, Time of the acquisition, Coherence, Meteorological conditions, Applications of SAR Interferometry. Interferometric SAR (InSAR) exploits the phase difference between two complex radar SAR observations of the same area, taken from slightly different sensor positions, and extracting distance information about the earth’s terrain. Persistent Scatterer Interferometry (PSI) is a branch of interferometry that exploits point scatterers, with strong radar backscatter, over a long period of time to provide a phase history of the point target over time.
Some applications of InSAR are: Geophysical monitoring of natural hazards
Time-series analysis of surface deformation, Glacier motion analysis, Digital elevation mapping, Principles of Image Interpretation
The Basic Elements of Image Interpretation are: Location of objects present
Size of the object, Shape of the object, Shadow, Tone and colour, Texture
Pattern, Height and depth, Site, situation and association. The shape of objects is described as the geometric form represented in an image. It is a good practice to orient the photos so that the shadows are falling towards the interpreter.
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