A two-dimensional region growing least squares phase unwrapping algorithm for interferometric SAR processing

This paper presents a new two-dimensional (2-D) phase unwrapping (PhU) algo rithm based on a least squares (LS) region growing strategy: the wrapped ph ase image is partitioned in different regions that are sequentially unwrapp ed via a LS algorithm. Reliable regions are dealt with at the beginning of the procedure, while critical areas are unwrapped in the final steps, thus avoiding error propagation from critical to reliable areas. ri conditioned least squares formulation of the phase unwrapping problem is the core of th e proposed procedure: this allows the solution to be tied to "some" known b oundary phase values, thus guaranteeing the correct joining of the reconstr ucted phase in between the different regions and preventing them from being independently unwrapped. The application of the finite element method allo ws a straightforward implementation of the algorithm in the discrete domain case. Experimental results, carried out on simulated and real interferomet ric SAR data, show the effectiveness of the proposed algorithm and the impr oved performances with respect to existing unwrapping procedures.