  A quantitative measure of quantum coherence was recently introduced, in the
context of quantum information theory. This measure has also been propounded as
a good quantifier of the wave nature of quantum objects. However, actually
measuring coherence in an experiment is still considered a challenge. A
procedure for measuring coherence in a multi-slit interference is proposed
here. It can be used for experimentally testing duality relations for
interference experiments involving more than two slits.
