Automatic classification of the telephone listening environment in a hearing aid

An algorithm is developed for automatic classification of the telephone-listening environment in a hearing instrument. The system would enable the hearing aid to automatically change its behavior when it is used for a telephone conversation (e.g., decrease the amplification in the hearing aid, or adapt the feedback suppression algorithm for reflections from the telephone handset). Two listening environments are included in the classifier. The first is a telephone conversation in quiet or in traffic noise and the second is a face-to-face conversation in quiet or in traffic. Each listening environment is modeled with two or three discrete Hidden Markov Models. The probabilities for the different listening environments are calculated with the forward algorithm for each frame of the input sound, and are compared with each other in order to detect the telephone-listening environment. The results indicate that the classifier can distinguish between the two listening environments used in the test material: telephone conversation and face-to-face conversation. [Work supported by GN ReSound.]