Enabling directional human-robot speech interface via adaptive beamforming and spatial noise reduction

This paper introduces a home robot application of multi-channel based spatial noise reduction for creating human-robot speech interfaces. A microphone array is employed first to create a speech-only directional conduit, which is realized through adaptive beamforming. Through the directional conduit, the intended speech signal from the desired direction is processed for detection and recognition, while unintended speech-like-sources or undesirable noise from other angles is suppressed. If speech signal is absent among the incoming signals through the conduit, further attenuation of undesirable signals is achieved by using a spatial noise reduction filter. Experimental validation of the technique was conducted using a computer simulation and also an online Samsung AnyBot test. Although the environments exhibited highly non-stationary noise, the method achieved an average speech recognition rate of 87.4% in the case of the computer simulation and 81.6% for the online Samsung AnyBot test. From the cases tested so far, the proposed implementation seems to be effective for practical robot applications in highly non-stationary noise environment.