Multilook coherent change detection

Abstract

Methods and devices use information from the original SAR images to provide measurements that can be applied to corresponding change detection products. This produces reliable registration and alignment for the change products even when the imaging geometry is significantly changed. A method of processing synthetic aperture radar, SAR, image data comprising a plurality of frames of SAR image data for each of a plurality of image geometries; for each image geometry, applying change detection to the frames of SAR image data corresponding to that image geometry to produce a corresponding plurality of change products; selecting a plurality of said acquired frames as reference frames, one in respect of each image geometry; applying a multilook SAR process to the reference frames to produce a multilook SAR product, the multilook SAR process comprising at least one processing stage comprising measuring a property of the data contained in the reference frames and applying a transformation to the data governed by the measured property; and applying a multilook change process to the change products, the multilook change process comprising applying the same transformation as in the multilook SAR process, to the change products, to produce a multilook change product.