A Wavelet-Based Change-Detection Technique for Multitemporal SAR Images

This paper presents a novel wavelet-based multiscale technique for unsupervised change detection in multitemporal synthetic aperture radar (SAR) images. The proposed approach is based on the analysis of a set of scale-dependent images characterized by a different trade-off between speckle reduction and preservation of geometrical details. The different scales are obtained by means of a multiresolution decomposition of the log-ratio image (obtained by a comparison of a pair of co-registered images acquired at different times on the same area). The final change-detection map is derived according to an adaptive scale-driven fusion algorithm, which properly exploits information at different resolution levels. According to an automatic local analysis of the statistic of the data, for each pixel only a sub-set of reliable scales is selected and exploited in the decision process thus producing an accurate and reliable change-detection map in both homogeneous and border areas. Experimental res...