The invention provides for a magnetic resonance imaging system (100) for acquiring magnetic resonance data (142) from a subject (118). The magnetic resonance imaging system comprises a processor (130) for controlling the magnetic resonance imaging system. The execution of the instructions causes the processor to control (200) the magnetic resonance imaging system with the pulse sequence data to acquire the magnetic resonance data. The pulse sequence data comprises commands for acquiring the magnetic resonance data using an n point Dixon magnetic resonance imaging method. The execution of the instructions causes the processor to construct (202) two phase candidate maps (144, 146) using the magnetic resonance data according to the n point Dixon magnetic resonance imaging method; divide (204) each of the set of voxels into a set of object voxels (148); identify (206) a set of boundary voxels (152) and interior voxels within the set of object voxels; create (208) a chosen phase candidate map (154) in the memory; select (210) a chosen phase map value for at least a portion of the set of boundary voxels in the chosen phase map from the two phase candidate maps by selecting the candidate phase map value which indicates the lowest fat to water ratio; and calculate (212) the phase map value of the object voxels according to a phase candidate selection algorithm.