Methods and apparatus for generating audio fingerprints for calls using power spectral density values

A system for processing an audio signal comprising:

• an audio fingerprinting device including a first processor, said first processor controlling the audio fingerprinting device to perform the following operations:
• removing silence from the audio signal, said audio signal being from a first call;
• after the silence has been removed from the audio signal, determining, for a plurality of time segments of the audio signal, power spectral density values of the audio signal for each of a plurality of N different frequency bins, N being an integer greater than 1;
• identifying (i) a plurality of dominant frequency peaks based on the determined power spectral density values, and (ii) positions in the audio signal corresponding to the identified peaks;
• generating a first audio fingerprint from at least some of the identified plurality of dominant frequency peaks and the identified positions in the audio signal corresponding to the identified peaks, said first audio fingerprint being an ordered set of information including:
• a first frequency bin value, a second frequency bin value, and a delta time, said first frequency bin value corresponding to a first dominant frequency peak, said first dominant frequency peak being one of the identified dominant frequency peaks, said second frequency bin value corresponding to a second dominant frequency peak, said second dominant frequency peak being one of the identified dominant frequency peaks, said first dominant frequency peak and said second dominant frequency peak being different dominant frequency peaks, said delta time being a time difference between a second identified location in the audio signal corresponding to the second dominant frequency peak and the first identified location in the audio signal corresponding to the first dominant frequency peak;
• generating a first set of fuzzy audio fingerprints from the first audio fingerprint by modifying one or more of:
• the first frequency bin value or the second frequency bin value, said first frequency bin value identifying a first range of frequencies corresponding to a first frequency bin, said second frequency bin value identifying a second range of frequencies corresponding to a second frequency bin;
• and
• using the first audio fingerprint and the first set of fuzzy audio fingerprints to determine whether the first call is a robocall;
• and
• wherein said modifying includes performing one of the following:
• (i) changing the first frequency bin value to a third frequency bin value, said third frequency bin value identifying a third range of frequencies corresponding to a third frequency bin, said third range of frequencies being different than said first range of frequencies,
• (ii) changing the second frequency bin value to a fourth frequency bin value, said fourth frequency bin value identifying a fourth range of frequencies corresponding to a fourth frequency bin, said fourth range of frequencies being different than said second range of frequencies, or
• (iii) changing the first frequency bin value to the third frequency bin value, said third frequency bin value identifying the third range of frequencies corresponding to the third frequency bin, said third range of frequencies being different than said first range of frequencies and changing the second frequency bin value to the fourth frequency bin value, said fourth frequency bin value identifying the fourth range of frequencies corresponding to the fourth frequency bin, said fourth range of frequencies being different than said second range of frequencies;
• and
• wherein said plurality of N different frequency bins includes said first frequency bin, said second frequency bin, said third frequency bin, and said fourth frequency bin.

A non-transitory computer readable medium including a first set of computer executable instructions which when executed by a processor of a computing device cause the computing device to:

• remove silence from an audio signal, said audio signal being from a first call;
• determine, for a plurality of time segments of the audio signal, power spectral density values of the audio signal for each of a plurality of N different frequency bins, N being an integer greater than 1;
• identify (i) a plurality of dominant frequency peaks based on the determined power spectral density values, and (ii) positions in the audio signal corresponding to the identified peaks;
• generate a first audio fingerprint from at least some of the identified plurality of dominant frequency peaks and the identified positions in the audio signal corresponding to the identified peaks, said first audio fingerprint being an ordered set of information including:
• a first frequency bin value, a second frequency bin value, and a delta time, said first frequency bin value corresponding to a first dominant frequency peak, said first dominant frequency peak being one of the identified dominant frequency peaks, said second frequency bin value corresponding to a second dominant frequency peak, said second dominant frequency peak being one of the identified dominant frequency peaks, said first dominant frequency peak and said second dominant frequency peak being different dominant frequency peaks, said delta time being a time difference between a second identified location in the audio signal corresponding to the second dominant frequency peak and the first identified location in the audio signal corresponding to the first dominant frequency peak;
• generate a first set of fuzzy audio fingerprints from the first audio fingerprint by modifying one or more of:
• the first frequency bin value or the second frequency bin value, said first frequency bin value identifying a first range of frequencies corresponding to a first frequency bin, said second frequency bin value identifying a second range of frequencies corresponding to a second frequency bin;
• and
• use the first audio fingerprint and the first set of fuzzy audio fingerprints to determine whether the first call is a robocall;
• and
• wherein said modifying includes performing one of the following:
• (i) changing the first frequency bin value to a third frequency bin value, said third frequency bin value identifying a third range of frequencies corresponding to a third frequency bin, said third range of frequencies being different than said first range of frequencies,
• (ii) changing the second frequency bin value to a fourth frequency bin value, said fourth frequency bin value identifying a fourth range of frequencies corresponding to a fourth frequency bin, said fourth range of frequencies being different than said second range of frequencies, or
• (iii) changing the first frequency bin value to the third frequency bin value, said third frequency bin value identifying the third range of frequencies corresponding to the third frequency bin, said third range of frequencies being different than said first range of frequencies and changing the second frequency bin value to the fourth frequency bin value, said fourth frequency bin value identifying the fourth range of frequencies corresponding to the fourth frequency bin, said fourth range of frequencies being different than said second range of frequencies;
• and
• wherein said plurality of N different frequency bins includes said first frequency bin, said second frequency bin, said third frequency bin, and said fourth frequency bin.

A method of processing an audio signal comprising:

• removing silence from the audio signal, said audio signal being from a first call;
• after the silence has been removed from the audio signal, determining, for a plurality of time segments of the audio signal, power spectral density values of the audio signal for each of a plurality of N different frequency bins, N being an integer greater than 1;
• identifying (i) a plurality of dominant frequency peaks based on the determined power spectral density values, and (ii) positions in the audio signal corresponding to the identified peaks;
• generating a first audio fingerprint from at least some of the identified plurality of dominant frequency peaks and the identified positions in the audio signal corresponding to the identified peaks, said first audio fingerprint being an ordered set of information including:
• a first frequency bin value, a second frequency bin value, and a delta time, said first frequency bin value corresponding to a first dominant frequency peak, said first dominant frequency peak being one of the identified dominant frequency peaks, said second frequency bin value corresponding to a second dominant frequency peak, said second dominant frequency peak being one of the identified dominant frequency peaks, said first dominant frequency peak and said second dominant frequency peak being different dominant frequency peaks, said delta time being a time difference between a second identified location in the audio signal corresponding to the second dominant frequency peak and the first identified location in the audio signal corresponding to the first dominant frequency peak;
• generate a first set of fuzzy audio fingerprints from the first audio fingerprint, said generating the first set of fuzzy audio fingerprints from the first audio fingerprint including modifying one or more of the following of the first audio fingerprint:
• the first frequency bin value or the second frequency bin value;
• and
• using the first audio fingerprint and the first set of fuzzy audio fingerprints to determine whether the first call is a robocall;
• and
• wherein said generating the first set of fuzzy audio fingerprints from the first audio fingerprint including modifying one or more of the following of the first audio fingerprint:
• the first frequency bin value or the second frequency bin value includes:
• generating a first fuzzy audio fingerprint and a second fuzzy audio fingerprint, said generating the first fuzzy audio fingerprint and the second fuzzy audio fingerprint including:
• generating the first fuzzy audio fingerprint by adding 1 to the first frequency bin value when the first frequency bin value is a value greater than 1 and less than 64;
• and
• generating the second fuzzy audio fingerprint by subtracting 1 from the first frequency bin value when the first frequency bin value is a value greater than 1 and less than 64;
• and
• generating the first fuzzy audio fingerprint by adding 2 to the first frequency bin value when the first frequency bin value is a value equal to or greater than 64 and less than 128;
• and
• generating the second fuzzy audio fingerprint by subtracting 2 from the first frequency bin value when the first frequency bin value is a value equal to or greater than 64 and less than 128;
• and
• generating the first fuzzy audio fingerprint by adding 4 to the first frequency bin value when the first frequency bin value is a value equal to or greater than 128 and less than 256;
• and
• generating the second fuzzy audio fingerprint by subtracting 4 from the first frequency bin value when the first frequency bin value is a value equal to or greater than 128 and less than 256.