Radar shadow detection in synthetic aperture radar images using digital elevation model and projections

Abstract:

Synthetic aperture radar (SAR) images are widely used in target recognition tasks nowadays. In this letter, we propose an automatic approach for radar shadow detection and extraction from SAR images utilizing geometric projections along with the digital elevation model (DEM) which corresponds to the given geo-referenced SAR image. First, the DEM is rotated into the radar geometry so that each row would match that of a radar line of sight. Next, we extract the shadow regions by processing row by row until the image is covered fully. We test the proposed shadow detection approach on different DEMs and a simulated 1D signals and 2D hills and volleys modeled by various variance based Gaussian functions. Experimental results indicate the proposed algorithm produces good results in detecting shadows in SAR images with high resolution.

Surface map movie showing the synthetic case as the Radar sight of line moves in positive z direction (H↑, H value increasing):

You can download the original movies in .mp4 format (Size 266 KB, lower quality) or .mov format (Size 360KB, better quality).

Contour map movie showing the synthetic case as the Radar sight of line moves in positive z direction (H↑, H value increasing):

You can download the original movies in .mp4 format (Size 205 KB, lower quality) or .mov format (Size 487KB, better quality).

Use VLC media player to view the animations. You can also obtain all the files together at figshare.

Shadow Detection - Examples:

Acknowledgment:

^$This work was done while the author was visiting IPAM, University of California Los Angeles, CA, USA. The author thanks the IPAM institute for their great hospitality and support during the visit.