Direction of arrival estimation in front of a reflective plane using a circular microphone array

The presence of reflecting surfaces inside an enclosure is generally known to have an adverse effect in acoustic source localization and Direction of Arrival (DOA) estimation performance. In this paper, we focus on the problem of indoor multi-source DOA estimation along the horizontal plane, considering a circular sensor array which is placed just in front of one of the vertical walls of the room. We present a modification in the propagation model, which traditionally accounts for the direct path only, by incorporating also the contribution of the earliest reflection introduced by the adjacent vertical wall. Based on the traditional and the modified model, a Matched Filter and a Minimum Variance Distortionless Response beamformer are designed and tested for DOA estimation. Results with simulated and real data demonstrate the validity of the proposed model and its superiority in comparison to the traditional one.