Probabilistic extraction and discovery of fundamental units in dolphin whistles

The study of dolphin cognition involves intensive research of animal vocalizations. Marine mammalogists commonly study a specific sound type known as the whistle found in dolphin communication. However, one of the main problems arises from noisy underwater environments. Often waves and splash noises will partially distort the whistle making analysis or extraction difficult. Another problem is discovering fundamental units that allow research of the composition of whistles. We propose a method for whistle extraction from noisy underwater recordings using a probabilistic approach. Furthermore, we investigate discovery algorithms for fundamental units using a mixture of hidden Markov models. We evaluate our findings with a marine mammalogist on data collected in the field. Furthermore, we have evidence that our algorithms enable researchers to form hypotheses about the composition of whistles.