Wavelet-based fusion of optical and SAR image data over urban area

In this paper, a fusion method is proposed, which provides an integrated map of an urban area starting from co-registered optical (panchromatic and multispectral) and SAR images. Classical Intensity-Hue-Saturation (IHS) transform based methods, or Principal Component Substitution (PCS) approaches do not take into account the contextual spatial information, and do not exploit conveniently the complementary characteristics of passive optical and radar data: they may provide interesting visual representations, but they do not guarantee definite advantages to a subsequent classification phase. The proposed method aims to generate an integrated map which selects specific information from SAR data to be injected into the optical data. This choice is application-dependent: in this paper, information related to buildings from the SAR image has been selected, since SAR point-targets strongly characterize urban areas.