Phase unwrapping via graph cuts

Abstract. This paper presents a new algorithm for recovering the absolute phase from modulo-2π phase, the so-called phase unwrapping (PU) problem. PU arises as a key step in several imaging technologies, from which we emphasize interferometric SAR and SAS, where topography is inferred from absolute phase measurements between two (or more) antennas and the terrain itself. The adopted criterion is the minimization of the L p norm of phase differences [1], [2], usually leading to computationally demanding algorithms. Our approach follows the idea introduced in [3] of an iterative binary optimization scheme, the novelty being the casting onto a graph max-flow/min-cut formulation, for which there exists efficient algorithms. That graph formulation is based on recent energy minimization results via graph-cuts [4]. Accordingly, we term this new algorithm PUMF (for phase unwrapping max-flow). A set of experimental results illustrates the effectiveness of PUMF.