Paper No: 74
Probabilistic Amplitude Demodulation
Author(s): Richard Turner, Maneesh Sahani
Auditory scene analysis is extremely challenging. One approach, perhaps that
adopted by the brain, is to shape useful representations of sounds on prior
knowledge about their statistical structure. For example, sounds with harmonic
sections are common and so time-frequency representations are efficient.
Most current representations concentrate on the shorter components. Here,
we propose representations for structures on longer time-scales, like the
phonemes and sentences of speech. We decompose a sound into a product of
processes, each with its own characteristic time-scale. This demodulation
cascade relates to classical amplitude demodulation, but traditional algorithms
fail to realise the representation fully. A new approach, probabilistic amplitude
demodulation, is shown to out-perform the established methods, and to easily
representation of a full demodulation cascade.