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US 9,521,249 B1Granted
Echo path change detector with robustness to double talk
AssigneeAmazon Technologies, Inc.
InventorAmit Singh Chhetri
Life of this patent
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Abstract
An echo path change detector may be used to control the rate of adaptation in an acoustic echo canceller. When echo path change is declared, the rate of adaptation may be increased. However, echo path change should not be declared in the presence of double talk, because rapid adaptation during double talk is undesirable. Accordingly, various features are disclosed for detecting echo path changes while avoiding the declaration of such changes in the presence of double talk.
Claims17
An acoustic echo cancellation device, comprising:
- a loudspeaker configured to generate a first signal;
- a microphone configured to generate a second signal;
- an acoustic echo canceller configured to generate a third signal characterizing an acoustic echo canceller output energy and a fourth signal characterizing an estimated echo energy, the acoustic echo canceller further configured to determine a first statistic characterizing an echo return loss enhancement from the second signal and the third signal;
- an echo path change detector configured to:
- determine a first product by multiplying the fourth signal with a first coefficient;
- determine a second product by multiplying the second signal with a second coefficient;
- determine a ratio of a first value divided by a sum of the first product and the second product;
- and
- determine a second statistic characterizing an echo path change from the third signal, the fourth signal, the second signal, and the ratio;
- and
- a processor configured to:
- determine that the second statistic is above a first threshold;
- determine that the first signal is above a second threshold;
- determine that the second signal is above a third threshold;
- determine that the first statistic is below a fourth threshold;
- and
- determine that an echo path change has occurred.
14 more elements
A method comprising:
- generating a third signal characterizing an acoustic echo canceller output energy and a fourth signal characterizing an estimated echo energy;
- determining a first statistic characterizing an echo return loss enhancement from a second signal generated by a microphone and the third signal;
- determining a first product by multiplying the fourth signal with a first coefficient;
- determining a second product by multiplying the second signal with a second coefficient;
- determining a ratio of a first value divided by a sum of the first product and the second product;
- determining a second statistic characterizing an echo path change from the third signal, the fourth signal, the second signal, and the ratio;
- determining that the second statistic is above a first threshold;
- determining that a first signal generated by a loudspeaker is above a second threshold;
- determining that the second signal is above a third threshold;
- determining that the first statistic is below a fourth threshold;
- and
- determining that an echo path change has occurred.
9 more elements
A system, comprising:
- means for generating a third signal characterizing an acoustic echo canceller output energy;
- means for generating a fourth signal characterizing an estimated echo energy;
- means for determining a first statistic characterizing an echo return loss enhancement from a second signal generated by a microphone and the third signal;
- means for determining a first product by multiplying the fourth signal with a first coefficient;
- means for determining a second product by multiplying the second signal with a second coefficient;
- means for determining a ratio of a first value divided by a sum of the first product and the second product;
- means for determining a second statistic characterizing an echo path change from the third signal, the fourth signal, the second signal, and the ratio;
- means for determining that the second statistic is above a first threshold;
- means for determining that a first signal generated by a loudspeaker is above a second threshold;
- means for determining that the second signal is above a third threshold;
- means for determining that the first statistic is below a fourth threshold;
- and
- means for determining that an echo path change has occurred.
10 more elements
Dependencies are inferred from the claim text.