Enhancement of Coherence Images for Coherent Change Detection
Konferenz: EUSAR 2021 - 13th European Conference on Synthetic Aperture Radar
29.03.2021 - 01.04.2021 in online
Tagungsband: EUSAR 2021
Seiten: 6Sprache: EnglischTyp: PDF
Horst, Hammer; Cadario, Erich; Kuny, Silvia (Fraunhofer IOSB, Fraunhofer Institute of Optronics, System Technologies and Image Exploitation, Ettlingen, Germany)
Lorenz, Fabian; Thiele, Antje (Fraunhofer IOSB, Fraunhofer Institute of Optronics, System Technologies and Image Exploitation, Ettlingen, Germany & Karlsruhe Institute of Technology KIT, Institute of Photogrammetry and Remote Sensing (IPF), Karlsruhe, Germany)
The coherent nature of SAR processing enables the generation of interferometric image pairs, in which the measure of coherence contains information about the temporal stability of the scene. This feature of repeat-pass interferometric data can be used to perform coherent change detection. Aiming towards this application, the contrast or rather the gray level differences between coherent and incoherent regions need to be maximized, so that subsequent change detection steps can perform best. Inspired by the classical coherence estimate, in this paper a workflow is presented to pre-process the image data for coherent change detection. The workflow contains several filtering steps to improve the contrast between coherent and incoherent areas of an image. It consists of three steps: Speckle filtering of the amplitudes, coherence-assisted removal of the topographic phase, and coherence-guided noise-filtering of the interferometric phase. The approach was tested with several speckle filters and several coherence estimation schemes.