  Doubletalk detector (DTD) is essential to keep adaptive filter from diverging
in the presence of near-end speech in acoustic echo cancellation (AEC), and
there was a receiver operating characteristic (ROC) to characterize DTD
performance. However, the traditional ROC for evaluating DTD used a static
time-invariant room acoustic impulse response and could not evaluate DTDs which
distinguish echo path change from doubletalk. We solve these problems by
extending the traditional binary detection ROC to three class, and simulations
show the efficiency of the proposed method.
