Extraction of power line maps from millimeter-wave polarimetric SAR images

Radar backscatter of power lines has lower values than those of the surroun ding ground clutter when the power line is oriented at an off-normal direct ion with respect to the radar line of sight. For power lines, the tradition al detection algorithms that are commonly based on the statistics of the ba ckscatter power of the clutter and target result in excessive false-alarm r ates due to very low signal-to-clutter ratio. In this paper, the applicatio n of a statistical polarimetric detection algorithm that significantly impr oves the signal-to-clutter ratio is demonstrated. The coherence between the co- and cross-polarized backscatter components is used as the detection pa rameter. This statistical detection parameter can be applied to any extende d targets such as a suspended cable in clutter background. Detection criter ia based on clutter backscattering coefficients, power line size, and aspec t angle, as well as the number of independent samples are obtained. The per formance of the algorithm for mapping power lines in SAR images is demonstr ated using a number of low-grazing incidence polarimetric SAR images at 35 GHz.