METHOD FOR UNWRAPPING 2-DIMENSIONAL PHASE SIGNALS

摘要

Many imaging techniques, including magnetic resonance imaging and interferometric synthetic aperture radar, produce phase-wrapped 2-dimensiona l signals (images and surfaces). In a phase-wrapped signal, the original signa l is measured modulus a known wavelength. We describe a new, computationally efficient algorithm for removing this type of distortion from 2-dimensional signals. Using the phase-wrapped signal as input, the algorithm infers the relative integer shifts between neighboring signal values by propagating belief vectors across a richly connected network that describes the relationships between the shifts. Belie f propagation is generally not guaranteed to converge to the correct answer in networks with cycles. However, we find experimentally that propagating shift beliefs across networks for phase unwrapping produces excellent estimates of the unwrapped signal.