Knuedge, Inc.

Friday Harbor LLC

Sean Michael O'Connor

Yao H Morin

David C Bradley

Massimo Mascaro

Ellisha Natalie Marongelli

Janis Intoy

Robert Nicholas Hilton

Nick Hilton

An input signal may be classified by computing correlations between feature vectors of the input signal and feature vectors of reference signals, wherein the reference signals correspond to a class. The feature vectors of the input signal and/or the reference signals may be segmented to identify portions of the signals before performing the correlations. Multiple correlations of the segments may be combined to produce a segment score corresponding to a segment. The signal may then be classified using multiple segment scores, for example by comparing a combination of the segment scores to a threshold.

Classifying signals using correlations of segments

An estimate of a fractional chirp rate of a signal may be computed by using multiple frequency representations of the signal. A first frequency representation may be computed using a first fractional chirp rate and a first score may be computed using the first frequency representation that indicates a match between the first fractional chirp rate and a fractional chirp rate of the signal. A second frequency representation may be computed using a second fractional chirp rate and a second score may be computed using the second frequency representation that indicates a match between the second fractional chirp rate and the fractional chirp rate of the signal. The fractional chirp rate of the signal may be estimated using the first score and the second score, for example, by selecting a fractional chirp rate corresponding to a highest score.

Estimating fractional chirp rate with multiple frequency representations

Features that may be computed from a harmonic signal include a fractional chirp rate, a pitch, and amplitudes of the harmonics. A fractional chirp rate may be estimated, for example, by computing scores corresponding to different fractional chirp rates and selecting a highest score. A first pitch may be computed from a frequency representation that is computed using the estimated fractional chirp rate, for example, by using peak-to-peak distances in the frequency distribution. A second pitch may be computed using the first pitch, and a frequency representation of the signal, for example, by using correlations of portions of the frequency representation. Amplitudes of harmonics of the signal may be determined using the estimated fractional chirp rate and second pitch. Any of the estimated fractional chirp rate, second pitch, and harmonic amplitudes may be used for further processing, such as speech recognition, speaker verification, speaker identification, or signal reconstruction.

Determining features of harmonic signals

An estimate of a pitch of a signal may be computed by using correlations of frequency portions of a frequency representation of the signal. An initial pitch estimate may be obtained and frequency portions of the frequency representation may be identified using multiples of the initial pitch estimate. Correlations of the frequency portions may be computed, and a score for the initial pitch estimate may be determined using the correlations. A second pitch estimate may be determined using the first score, and the process may be repeated.

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Sean Michael O'Connor