In-vehicle noise cancellation adaptive filter divergence control
AssigneeHarman International Industries, Incorporated
InventorsKevin J. BASTYR, David TRUMPY, Shiyu CHEN
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Abstract
A active noise cancellation (ANC) system may include an adaptive filter divergence detector for detecting divergence of the one or more controllable filters as they adapt, based on various temporal or frequency domain amplitude characteristics. Upon detection of a controllable filter divergence, the ANC system may be deactivated, or certain speakers may be muted. Alternatively, the ANC system may modify the diverged controllable filters to restore proper operation of the noise cancelling system. This may include adjusting a leakage value of an adaptive filter controller.
Claims20
A method for controlling stability in an active noise cancellation (ANC) system, the method comprising:
- receiving, from an adaptive filter controller, filter coefficients corresponding to at least one controllable filter;
- computing a parameter based on an analysis of at least a portion of the filter coefficients;
- comparing the parameter from a current adaptation of the at least one controllable filter to an average value of a same parameter from one or more previous adaptations of the at least one controllable filter;
- and
- modifying properties of the at least one controllable filter in response to a difference between the parameter computed from the current adaptation of the at least one controllable filter and the average value of the same parameter from the one or more previous adaptations of the at least one controllable filter exceeding a threshold.
An active noise cancellation (ANC) system comprising:
- at least one controllable filter configured to generate an anti-noise signal based on an adaptive transfer characteristic and a noise signal received from a sensor, the adaptive transfer characteristic of the at least one controllable filter characterized by a set of filter coefficients;
- an adaptive filter controller, including a processor and memory, programmed to adapt the set of filter coefficients based on the noise signal and an error signal received from a microphone located in a cabin of a vehicle;
- and
- a divergence controller in communication with at least the adaptive filter controller, the divergence controller including a processor and memory programmed to:
- receive the set of filter coefficients corresponding to a current adaptation of the adaptive transfer characteristic of the at least one controllable filter;
- compute a parameter based on an analysis of at least a portion of the set of filter coefficients;
- detect divergence of the at least one controllable filter based on a comparison of the parameter to a threshold, wherein the threshold is a dynamic threshold computed from a statistical analysis of the parameter computed from filter coefficients in one or more preceding adaptations of the at least one controllable filter and;
- and
- transmit an adjustment signal to the adaptive filter controller causing it to modify properties of the at least one controllable filter that has diverged.
A computer-program product embodied in a non-transitory computer readable medium that is programmed for active noise cancellation (ANC), the computer-program product comprising instructions for:
- receiving, from an adaptive filter controller, a set of filter coefficients corresponding to a current adaptation of at least one controllable filter;
- computing a parameter based on an analysis of at least a portion of the filter coefficients;
- comparing the parameter to a threshold, wherein the threshold is a dynamic threshold computed from a statistical analysis of the parameter computed from filter coefficients in one or more preceding adaptations of the at least one controllable filter;
- and
- modifying an adaptive transfer characteristic of the at least one controllable filter during the current adaptation in response to the parameter exceeding the threshold.
Dependencies are inferred from the claim text.