Linear Signatures in Urban SAR Images—Partly Misinterpreted?

Corner lines, line signatures related to building facades in synthetic aperture radar images, are commonly related to signal double reflections, either specular or diffuse. However, the scene properties, i.e., building orientation, building shape, and surface roughness, often do not correspond to this expectation. This letter presents a 3-D representative simulation case study, based on ray tracing and a detailed facade model, in order to analyze the origin of corner lines at facades. The simulation results indicate that the intensity of corner lines may be dominated by signal triple reflections of different types.