  At present, quantum channels have been widely concerned, and many ways to
quantify quantum channels have been proposed, which has led to the generation
of many resource theories for quantum channels. We add strong monotonicity and
convexity to the requirement of imaginarity measure of quantum channels to make
the measure proper. We also introduce an alternative framework to simplify the
process of verifying whether a quantifier is a proper measure. We present three
imaginarity measures of quantum channels via on the robustness, the trace norm
and entropy, respectively. Some properties are also given.
