  Quantum nonlocality is a kind of significant quantum correlation that is
stronger than quantum entanglement and EPR steering. The standard tripartite
nonlocality can be detected by the violation of the Mermin inequality. By using
local filtering operations, we give a tight upper bound on the maximal expected
value of the Mermin operators. By detailed examples we show that the hidden
standard nonlocality can be revealed by local filtering which can enhance the
robustness of the noised entangled states.
