Automatic Image-to-image Registration of near Real-time Sar Images

This paper deals with the registration of near real-time satellite SAR images by an automatic image-to-image matching approach. The approach is dedicated to crisis mapping applications where the task is to register near real-time (NRT) SAR images within some hours against a reference image. Our registration strategy exists of the following steps: Feature extraction and matching between a NRT image and an image with precise orbit. The resultant points of the reference image are used as ground control points (GCPs) for an adjustment of the SAR imaging geometry. Then, geocoding of the NRT SAR image can be carried out. The main task is to find a feature extractor, which performs well on SAR data. We use a new point operator for feature extraction to extract scaleand rotation-invariant features (SIFT-features). The results show that the approach can deal with a wide range of scenes even with different SAR sensors and different incidence angles.