Disambiguation in determining phonemes of sound-imitation words for environmental sound recognition

Onomatopoeia, or sound-imitation words (SIWs) are important in informing sound events in human-computer communication. One problem is listener-dependency in recognizing environmental sounds by means of SIWs, that is, different listener hears the same environmental sound as a different SIW even under the same condition. Therefore, the use of usual Japanese phonemes is not adequate to express SIWs. To cope with this ambiguity problem of phoneme determination, we designed a set of new phonemes, referred to as the basic phoneme-groups, to represent environmental sounds. The basic phoneme-group consists of one or more Japanese phonemes, and thus the ambiguity problem is resolved based on it by generating one or more SIWs for a sound event. An HMM-based scheme is adopted to recognize SIWs using the phoneme-groups. Listening experiments with seven subjects showed that automatic SIW recognition based on the basic phoneme-groups outperformed ones based on the other types of phonemes. The recall and precision rate were 56.4% and 72.2%, respectively.