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US 8,507,781 B2Granted
Rhythm recognition from an audio signal
AssigneeHarman International Industries Canada Limited
InventorsPeter R. Lupini, Glen A. Rutledge, William Norman Campbell
Life of this patent
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Abstract
A guitar delay engine such as a multi-tap delay pedal or other rhythm engine such as a vocal multi-tap delay pedal, a drum machine, or any other device that requires setting a rhythmic pattern (i.e. level and timing information) for operation is provided. In a guitar delay device, the guitarist can hold down a foot pedal, play a rhythmic pattern on their guitar, and then release the foot pedal and have the rhythmic pattern just played emulated in the delay pattern on the device.
Claims29
A method, comprising:
- receiving a digital audio signal from a musical instrument;
- analyzing the received digital audio signal to detect events in the digital audio signal;
- selecting events from the detected events based on a score associated with the events;
- extracting a rhythmic pattern based on the selected events;
- and
- generating an acoustic signal based on the extracted rhythmic pattern so as to accompany an acoustic signal from the musical instrument.
3 more elements
A method for determining rhythms, comprising:
- receiving a digital audio signal from a musical instrument;
- analyzing the received digital audio signal to detect events in the digital audio signal;
- selecting events from the detected events based on a score associated with the events;
- extracting a rhythmic pattern based on the selected events;
- and
- communicating the rhythmic pattern, wherein events are detected by:
- estimating an energy envelope of the received digital audio signal in one or more frequency bands;
- estimating a derivative of the energy envelope in one or more frequency bands;
- identifying at least two peaks in the derivative;
- and
- associating the at least two peaks with corresponding events, wherein timing information is extracted based on times associated with the peaks.
8 more elements
A method for determining rhythms, comprising:
- receiving a digital audio signal from a musical instrument;
- analyzing the received digital audio signal to detect events in the digital audio signal;
- selecting events from the detected events based on a score associated with the events;
- extracting a rhythmic pattern based on the selected events, wherein the extracted rhythmic pattern includes at least one pattern period and beat time location within the rhythmic pattern and the rhythmic pattern is extracted by locating at least one pattern period repetition, wherein the at least one pattern period repetition is located by:
- grouping events into candidate repeating periods;
- matching events between the repeating periods;
- establishing a cost for each set of matched events based on a temporal distance between the matching events;
- increasing the cost for each set of matched events based on a number of events that are unmatched between the repeating periods;
- determining overall costs based on the established costs and the increased costs;
- and
- selecting at least one repeating pattern based on the determined costs.
8 more elements
At least one computer readable storage medium having computer-executable instructions for a method comprising:
- analyzing a received digital audio signal from a musical instrument to detect events in the digital audio signal;
- selecting events from the detected events based on scores associated with the events;
- and
- extracting a rhythmic pattern based on the selected events;
- and
- generating a rhythmic acoustic signal based on the extracted rhythm pattern so as to accompany an acoustic signal from the musical instrument.
3 more elements
An apparatus, comprising:
- an input configured to receive a digital audio signal from a musical instrument;
- a processor configured to
- analyze the received digital audio signal to detect events in the digital audio signal,
- select events from the detected events based on scores associated with the events, and
- extract a rhythmic pattern based on the selected events;
- and
- an output configured to deliver the rhythmic pattern so as to produce an accompaniment acoustic signal based on the extracted rhythmic pattern.
4 more elements
An apparatus, comprising:
- an input configured to receive a digital audio signal from a musical instrument;
- a processor configured to
- analyze the received digital audio signal to detect events in the digital audio signal,
- select events from the detected events based on scores associated with the events, and
- extract a rhythmic pattern based on the selected events;
- and
- an output configured to deliver the rhythmic pattern, wherein the processor is configured to search for a repeating pattern by:
- grouping events into candidate repeating periods;
- matching events between the repeating periods;
- establishing a cost for each set of matched events based on a temporal distance between the matching events;
- increasing the cost for each set of matched events based on a number of events that are unmatched between the repeating periods;
- determining overall costs based on the established costs and the increased costs;
- and
- selecting at least one repeating pattern based on the determined costs.
11 more elements
An apparatus, comprising:
- an input configured to receive a digital audio signal from a musical instrument;
- a processor configured to:
- analyze the received digital audio signal to detect events in the digital audio signal,
- select events from the detected events based on scores associated with the events, and
- extract a rhythmic pattern based on the selected events;
- wherein the processor is configured to detect events by:
- estimating an energy envelope of the received digital audio signal in one or more frequency bands;
- estimating a derivative of the energy envelope in one or more frequency bands;
- identifying at least two peaks in the derivative;
- and
- associating the at least two peaks with corresponding events, wherein timing information is extracted based on times associated with the peaks;
- and
- an output configured to deliver the rhythmic pattern.
10 more elements
A method, comprising:
- receiving a digital audio signal associated with a musical instrument;
- analyzing the received digital audio signal to detect events in the digital audio signal;
- selecting events from the detected events based on a score associated with the events;
- extracting a rhythmic pattern based on the selected events;
- and
- generating an acoustic signal based on the extracted rhythmic pattern and a second audio signal from the musical instrument.
3 more elements
An apparatus, comprising:
- a processor configured to:
- analyze a first digital audio signal from a musical instrument to detect events in the digital audio signal,
- select events from the detected events based on scores associated with the events,
- extract a rhythmic pattern based on the selected events, and
- apply a delay pattern based on the extracted rhythmic pattern to a second audio signal from the musical instrument.
2 more elements
Dependencies are inferred from the claim text.