  Most previously proposed dual-channel coherent-to-diffuse-ratio (CDR)
estimators are based on a free-field model. When used for binaural signals,
e.g., for dereverberation in binaural hearing aids, their performance may
degrade due to the influence of the head, even when the direction-of-arrival of
the desired speaker is exactly known. In this paper, the head shadowing effect
is taken into account for CDR estimation by using a simplified model for the
frequency-dependent interaural time difference and a model for the binaural
coherence of the diffuse noise field. Evaluation of CDR-based dereverberation
with measured binaural impulse responses indicates that the proposed binaural
CDR estimators can improve PESQ scores.
