Time-frequency distribution of partial phonetic information measured using mutual information

This paper uses the method of mutual information to estimate the distribution of partial phonetic information in the time-frequency plane relative to an acoustic landmark. TIMIT transcriptions are parsed to estimate the locations of consonant closure landmarks, consonant release landmarks, manner change landmarks, and vowel or glide pivot landmarks. A mel-scale spectrogram is computed over the 250ms centered at each landmark, and the logarithmic energy of each point in time-frequency space is linearly quantized. The phoneme label associated with a landmark determines the values of 25 binary distinctive features. Finally, coincidences between feature and spectral energy values are counted, and the average log probabilities are calculated in order to produce an "infogram" of each distinctive feature: a measurement of the mutual information between the value of the feature and the energy of each point in the time-frequency plane.