2010 Volume 31 Issue 5 Pages 309-319
In this work, the perception of the position and orientation of a directional acoustic source in a real enclosed environment by blindfolded listeners is investigated and compared with a method that automatically estimates the position and orientation of the source using a T-shaped microphone array. In the subjective experiment using blindfolded listeners, a human speaker acted as an acoustic source and listeners judged the speaker’s facing angle (one out of four possible orientations shifted by 90°) and position after listening to a spoken sentence. This procedure was performed twice, before and after a training phase. In the training, listeners were allowed to remove the blindfold and verify the speaker’s position and orientation. After the training, the correct orientation ratio increased from 75.0 to 76.5% and the average position error decreased from 66.2 to 60.6 cm. In addition, a subjective experiment on orientation estimation with eight orientations shifted by 45° in the same real environment showed that orientation estimation in a real environment was more difficult than that in an anechoic environment. Artificial neural networks (ANNs) were used in the automatic estimation method. A correct orientation ratio of 68.1% and an average position error of 48.0 cm were obtained by the T-shaped microphone array located nearest to the blindfolded listener among an array network consisting of eight T-shaped microphone arrays, enabling a rough comparison between human auditory perception and the automatic estimation method (a correct orientation ratio of 67% and a better average position error of 38.6 cm were the best results obtained by a T-shaped array in the network). It was clarified that the automatic estimation method cannot surpass the auditory system in terms of correct orientation ratio; however, it yielded better results in terms of the average position error.
