Linear structures in SAR coherence data

Abstract

The extraction of thin linear structures like roads, rivers and railway lines from synthetic aperture radar (SAR) scenes has been shown to be a difficult task owing to the speckle effects of coherent imaging (e.g. Hendri et al., 1988), Therefore, for line extraction it is reasonable to use all information that SAR scenes offer, and not only the amplitude data. One source of additional information is the coherence data computed by interferometric processing of two SAR scenes. The visibility of linear structures in SAR coherence data has been investigated. Scene pairs from the ERS-1 and the ERS-2 SAR sensors, the X-SAR experiment and a scene from a two-antenna airborne SAR system were evaluated The time difference between the acquisitions of the spaceborne scenes forming interferometric scene pairs was one to 35 days. An optimal size of the correlation window used to derive coherence maps for linear structure extraction was determined by visual inspection. The correlation between the intensity and the coherence data was used to infer how much information the coherence adds to the information of the amplitude of both scenes.