  In this paper, we investigate the quantum coherence extraction for two
accelerating Unruh-DeWitt detectors coupling to a scalar background in $3+1$
Minkowski spacetime. We find that quantum coherence as a sort of nonclassical
correlation can be generated through the Markovian evolution of the detectors
system just like quantum entanglement. However, with growing Unruh temperature,
in contrast to monotonous degrading entanglement, we find that quantum
coherence exhibits a striking revival phenomenon. That is, for certain choice
of detectors' initial state, coherence measure will reduce to zero firstly then
grow up to an asymptotic value. We verify such coherence revival by inspecting
its metrological advantage on enhancing the quantum Fisher information (QFI).
Since the maximal QFI bounding the accuracy of a quantum measurement, we
conclude that the extracted coherence can be utilized as a physical resource in
quantum metrology.
