A Multi-chromatic Approach to SAR Interferometry: Differential Analysis of Interferograms at Close Frequencies in the Spatial Domain and Frequency Domain

The differential analysis in the frequency domain, or multi-chromatic approach to SAR-interferometry, offers as its main advantage the retrieval of the absolute phase of targets, providing an alternative to the phase unwrapping algorithms in the spatial domain. On the other hand, a correct segmentation of fringe pattern obtained from wrapped phase fields is essential to the aim of assigning at each pixel of a fringe the right value of integer 2pi-multiples. In this paper the authors show that interferograms at adjacent frequencies can be combined in order to improve the edge detection among interferometrical fringes in areas affected by different kind of phase ambiguities, thus widening the extension of segmented areas.