  Based on the theory of quantum mechanics, intrinsic randomness in measurement
distinguishes quantum effects from classical ones. From the perspective of
states, this quantum feature can be summarized as coherence or superposition in
a specific (classical) computational basis. Recently, by regarding coherence as
a physical resource, Baumgratz et al.~present a comprehensive framework for
coherence measures. Here, we propose a quantum coherence measure essentially
using the intrinsic randomness of measurement. The proposed coherence measure
provides an answer to the open question in completing the resource theory of
coherence. Meanwhile, we show that the coherence distillation process can be
treated as quantum extraction, which can be regarded as an equivalent process
of classical random number extraction. From this viewpoint, the proposed
coherence measure also clarifies the operational aspect of quantum coherence.
Finally, our results indicate a strong similarity between two types of
quantumness --- coherence and entanglement.
