Journal article
Change Detection for Thematic Mapping by Means of Airborne Multitemporal Polarimetric SAR Imagery
The paper addresses the detection of changes in multitemporal polarimetric radar images, focusing on small objects and narrow linear features. The images were acquired at C- and L-band by the airborne EMISAR system. It is found that the radar intensities are better suited for change detection than the correlation coefficient and the phase difference between the co-polarized channels.
In the case of linear features, there is no obvious difference between the C- and L-bands , and slight variations of the flight tracks are acceptable at look angles larger than 35 degrees. Theoretical detection thresholds are evaluated from the statistical distribution of the intensity ratio due to speckle.
For the linear features and for urban environments, the observed thresholds are larger than the theoretical predictions. This is interpreted as an effect of radar intensity variations on length scales smaller than the spatial image resolution. The signature of urban areas is very sensitive to deviations between the flight tracks, and the sensitivity is larger at C-band than at L-band.
On the other hand, the intensity contrast between buildings and the urban background is smaller at L-band and larger at C-band. For change detection, thresholds may have to be chosen separately for each object class because the intensity ratios of different object classes vary differently as a function of time.
Language: | English |
---|---|
Publisher: | IEEE |
Year: | 2002 |
Pages: | 618-636 |
ISSN: | 15580644 and 01962892 |
Types: | Journal article |
DOI: | 10.1109/TGRS.2002.1000322 |
ORCIDs: | Skriver, Henning |
C-band Image resolution L-band Object detection Phase detection Radar detection Radar imaging Radar polarimetry Radar tracking Speckle Statistical distributions airborne EMISAR system airborne multitemporal polarimetric SAR imagery airborne radar change detection co-polarized channels detection thresholds feature extraction geophysical signal processing image recognition image resolution intensity ratio linear features narrow linear features radar images radar imaging radar intensities radar polarimetry small objects speckle statistical distribution synthetic aperture radar thematic mapping urban areas