Surface penetrating imaging technology reconstructs target images that conform to visual perception by interpreting radar data, which reflects the target's geometry and electromagnetic scattering characteristics directly. For surface penetration imaging, various sources of clutter cause failure of image interpretation, therefore clutter suppression is the key to obtain target information accurately. Though clutter suppression approaches aiming at the strong clutter make the target image prominent enough for imaging process, the weak clutter with energy close to the target affects the imaging quality. In this paper, a nonlinear gain control method is proposed for the suppression of weak clutter and improving the contrast of the imaging by non-linearly weakening the data below the threshold and enhancing the data above the threshold. Experiments show that the proposed method can effectively improve the imaging quality.
Accurate co-registration of SAR image is a crucial step in interferometry SAR (InSAR) processing, and lower registration accuracy will lead to more interferometry phase error. The most commonly used is 2-D polynomial function registration method (2-DR), which is simple and works well in most conditions. But in the case of long baselines and complex terrain scene, (2-DR) can not meet the precision requirements. The DEM-assisted geometrical SAR image registration method (GeoR), which use the external DEM and orbit data to calculate offsets, can theoretically achieve an ideal precision for any baseline and terrain. In GeoR, corresponding elevation value of each pixel in the master image needs to extracted from the external DEM. Unfortunately, there are errors in the DEM data and the orbit data, which often result in approximate horizontal shift error and mismatch between DEM and SAR image, caused low precision elevation value extraction and eventually degrade the registration performance. In this paper, the influences of DEM error and orbital error in elevation value extraction are firstly analyzed, and then an improved geometrical SAR image registration method based on elevation correction (I-GeoR) is proposed. In elevation correction, Elevation value in DEM can be correctly assigned to each pixel of the image, which is achieved by deformation extraction that based on SAR image simulation. Finally, two ALOS-PALSAR images are processed to vaidate the new method. The result shows that I-GeoR can effectively correct the elevation and has a higher registration precision.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.