Head orientation estimation of a speaker by utilizing kurtosis of a DOA histogram with restoration of distance effect

In this paper, we propose a head-orientation estimation method from multichannel acoustic signals. Sharpness of a DOA histogram which is extracted by using the sparseness based DOA estimation method varies depending on the head orientation of a speaker. The proposed method utilizes this phenomenon to estimate the head orientation of the speaker. The proposed method uses more than two microphone arrays. In addition to estimation of the speaker location, the proposed method estimates kurtosis of the DOA histogram of each array. Kurtosis is regarded as a measure of sharpness of a DOA histogram in the proposed method. However, kurtosis also depends on the distance between the speaker and the microphone array (distance effect). The distance effect is experimentally revealed by the regression analysis. The head orientation of a speaker is estimated by the restored kurtosis which is free from the distance effect. Experimental results on a reverberant environment show that the proposed method can estimate the head orientation of a speaker more accurately than a conventional head-orientation estimation method.