IMPROVED BRANCH-CUT ALGORITHM FOR MULTIBASELINE PHASE UNWRAPPING USING SAR INTERFEROGRAMS

Multi-baseline (MB) phase unwrapping (PU) is an important processing stage of MB synthetic aperture radar (SAR) interferometry (InSAR). Compared with the traditional single-baseline (SB) PU, MB PU is more applicable to the mountainous area, which does not follow the Itoh condition. A two-stage programming MB PU approach (TSPA) proposed by H. Yu, which builds the link between SB and MB PUs, so many existing classical SB PU methods can be transplanted into MB domain. In this paper, an extended Goldstein's Branch-cut algorithm for MB InSAR using the TSPA, abbreviated as TSPA-BC, is proposed, consisting of three steps. In step 1, the MB residues are identified according to the phase gradients estimated by TSPA based on CRT. In step 2, the MB branch cuts with global minimal length are generated, which is equal to the MB..0 -norm branch-cut length. In step 3, the final PU result are obtained by a flood-fill integration process using the phase gradients obtained by stage 1 in which the integration path does not pass through any MB branch cut. The experimental results of TanDEM-X MB dataset illustrate that the effectiveness of the TSPA-BC method in the rugged area.