Source separation using a circular model
AssigneeAnalog Devices, Inc.
InventorsJohannes Traa, Paris Smaragdis
Life of this patent
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Abstract
An approach to separating multiple sources exploits the observation that each source is associated with a linear-circular phase characteristic in which the relative phase between pairs of microphones follows a linear (modulo) pattern. In some examples, a modified RANSAC (Random Sample Consensus) approach is used to identify the frequency/phase samples that are attributed to each source. In some examples, either in combination with the modified RANSAC approach or using other approaches, a wrapped variable representation is used to represent a probability density of phase, thereby avoiding a need to “unwrap” phase in applying probabilistic techniques to estimating delay between sources.
Claims15
A method for separating source signals from a plurality of sources using a plurality of sensors, the method comprising:
- accepting a first signal at each of the sensors, the first signal including a combination of multiple of the source signals, each sensor providing a corresponding first sensor signal representing the first signal;
- for each of a set of pairs of sensors,
- determining phase values for a plurality of frequencies of the pair of the first sensor signals provided by the pair of sensors, and
- estimating a parametric relationship between phase and frequency for each of a plurality of signal sources included in the sensor signals, the parametric relationship characterizing a periodic distribution of phase at each frequency for each source;
- accepting a second signal at each of the sensors, each sensor providing a corresponding second sensor signal representing the second signal;
- for each of a set of pairs of sensors,
- determining phase values for a plurality of frequencies of the pair of the second sensor signals accepted at the pair of sensors;
- and
- forming a frequency mask corresponding to a desired source of the plurality of sources from the determined phase values of the second sensor signals and the periodic distribution of phase characterized by the parametric relationships estimated from the first signals.
A signal processing system comprising:
- an plurality of sensor inputs, each for coupling to a corresponding one of a plurality of sensor and accepting a corresponding sensor signal;
- a computer-implemented processing module configured to, for each of a set of pairs of sensor signals,
- determine phase values for a plurality of frequencies of the pair of first sensor signals accepted at the sensor inputs, and
- estimate a parametric relationship between phase and frequency for each of a plurality of signal sources represented in the first sensor signals, the parametric relationship characterizing a periodic distribution of phase at each frequency for each source,
- determine phase values for a plurality of frequencies of the pair of second sensor signals accepted at the sensor inputs;
- and
- wherein the processing module is further configured to form and store a frequency mask corresponding to a desired source of the plurality of sources from the determined phase values of the second sensor signals and the periodic distribution of phase characterized by the parametric relationships estimated from the first signals.
Software stored on a non-transitory machine-readable medium comprising instructions for causing a signal processor to:
- accept sensor signals at a plurality of sensor inputs;
- for each of a set of pairs of sensor signals,
- determine phase values for a plurality of frequencies of the pair of first sensor signals accepted at the sensor inputs, and
- estimate a parametric relationship between phase and frequency for each of a plurality of signal sources represented in the first sensor signals, the parametric relationship characterizing a periodic distribution of phase at each frequency for each source,
- determine phase values for a plurality of frequencies of the pair of second sensor signals accepted at the sensor inputs;
- and
- to form and store a frequency mask corresponding to a desired source of the plurality of sources from the determined phase values of the second sensor signals and the periodic distribution of phase characterized by the parametric relationships estimated from the first signals.
Dependencies are inferred from the claim text.