<title>Segmentation of moving objects in SAR-MTI data</title>

The SAR processing is optimized for motionless scenes. Moving objects cause artifacts like blurring or azimuth displacement in case of parallel or radial velocity components respectively. With along-track interferometry (SAR-MTI) even very slow radial velocities can be measured by the phase differences. Unfortunately, the phase information is often severely disturbed, depending on a insufficient signal to noise ratio. In this paper we refer to investigations to stabilize and improve the SAR-MTI velocity data. Reliability is enhanced by a combined exploitation of phase and intensity. After speckle filtering a binary mask is generated from the intensity data to fade out regions with insufficient signal to noise ratio, like regions with low backscattering coefficient. In a next step for every point in the intensity image the radial velocity is calculated by the phase difference of two channels. This image of velocities is masked with the binary mask derived from the intensity image. A region growing process is initiated in the velocity image to identify connected regions in the image with similar velocity. By this process we get first hints for moving objects. The approach was applied to images with slow moving cargo ships inside and nearby locks. The cargo ships are segmented and described by a simple model. Only cargo ships with a minimum velocity which match the longitudinal and transversal extension features of the model are concerned in further processing