Method and apparatus for in-ear canal sound suppression
View Patent ↗An earpiece ( 100 ) and acoustic management module for in-ear canal suppression control are provided. A method for suppressing signals for a conference call, a vehicle, and a general communication event is also provided. The earpiece can include an Ambient Sound Microphone ( 111 ) to capture ambient sound, an Ear Canal Receiver ( 125 ) to deliver audio content to an ear canal, an Ear Canal Microphone ( 123 ) configured to capture internal sound, and a processor ( 121 ). The processor can generate a voice activity level ( 622 ) and suppress an echo, spoken voice, and media content in the electronic internal signal, and mix an electronic ambient signal with an electronic internal signal in a ratio dependent on the voice activity level and a background noise level to produce a mixed signal ( 323 ) that is delivered to the ear canal ( 131 ).
1. A method of listening to an audio content signal during a full duplex communication event, the method comprising the steps of:
delivering the audio content signal to an ear canal of a first user by way of an Ear Canal Receiver (ECR) to produce an acoustic audio content;
capturing in the ear canal of the first user by way of an Ear Canal Microphone (ECM) an electronic signal comprising the acoustic audio content and a spoken voice of the first user in a presence of the acoustic audio content;
adaptively filtering the electronic signal using the audio content signal as a reference signal, to suppress the acoustic audio content in the electronic signal while preserving the spoken voice to produce a modified electronic signal;
determining a voice activity level of vowels in the spoken voice of the first user based on the modified electronic signal, the voice activity level indicating a degree of voicing of the vowels in the spoken voice that identifies periodic vibrations of vocal cords by the first user;
adjusting a gain of the audio content signal as a function of a measured background noise level and the voice activity level of the vowels with respect to the measured background noise level to form an adjusted signal, the adjusted signal being provided to the ear canal of the first user via the ECR during the full duplex communication event; and
sending the modified electronic signal to at least one other user so that the acoustic audio content is sufficiently inaudible and simultaneously the spoken voice is audible to the at least one other user during the full duplex communication event.
2. The method of claim 1 where the step of adaptively filtering includes the step of:
suppressing the acoustic audio content in the electronic signal in accordance with the function to produce the modified electronic signal when the voice activity level is above a first predetermined threshold.
3. The method of claim 2 further including a step of adapting a first set of filter coefficients of a Least Mean Squares (LMS) filter to model an inner ear-canal microphone transfer function (ECTF) of the first user.
4. The method of claim 3 further including the steps of:
monitoring the voice activity level of the modified electronic signal; and
freezing an adaptation of the first set of filter coefficients for the modified electronic signal if the voice activity level is above the first predetermined threshold.
5. The method of claim 4 , further including the steps of:
adapting a second set of filter coefficients for a replica of the LMS filter; and
substituting the second set of filter coefficients for the first set of filter coefficients when the voice activity level is below a second predetermined threshold.
6. The method of claim 5 further including suppressing the modified electronic signal when the voice activity level is below the second predetermined threshold to prevent the acoustic audio content from being sent.
7. The method of claim 1 where the voice activity level is determined by an energy level characteristic and a frequency response characteristic of the spoken voice.
8. The method of claim 1 further including a step of controlling a mixing of the audio content signal and a signal received from the at least one other user based on the voice activity level.
9. The method of claim 8 further including the steps of:
increasing the gain of the audio content signal as the voice activity level of the first user decreases, while
decreasing a gain of a signal received from the at least one other user as the voice activity level of the first user decreases, or
decreasing the gain of the audio content signal as the voice activity level of the first user increases, while
increasing the gain of the signal received from the at least one other user as the voice activity level of the first user increases.
10. The method of claim 1 where the audio content signal includes at least one of music, media content or a voice communication signal.
11. A method of listening to audio content comprising the steps of:
providing the audio content to an ear canal of a first user from a first transducer coupled to a communication device to produce acoustic audio content;
engaging in a full duplex voice communication with the communication device where a spoken voice of the first user and the acoustic audio content are captured by a second transducer in the ear canal;
adaptively filtering an output signal of the second transducer using the audio content to produce a modified output signal, to suppress the acoustic audio content from a transmitted signal from the communication device such that participants receiving the transmitted signal hear the spoken voice of the first user of the communication device but simultaneously the acoustic audio content is inaudible to the participants receiving the transmitted signal;
determining a voice activity level of vowels in the spoken voice of the first user based on the modified output signal, the voice activity level indicating a degree of voicing of the vowels in the spoken voice that identifies periodic vibrations of vocal cords by the first user during a full duplex voice communication event; and
adjusting a gain of the audio content as a function of a measured background noise level and the voice activity level of the vowels with respect to the measured background noise level to form an adjusted signal, the adjusted signal being provided to the ear canal via the first transducer during the full duplex voice communication event.
12. The method of claim 11 including:
suppressing the acoustic audio content in the electronic signal in accordance with the function to produce the modified electronic signal, where the audio content includes at least one of music or media content.
13. The method of claim 11 further including sending the modified output signal having no information when the voice activity level of the spoken voice of the user of the communication device is below a predetermined threshold, where the participants receiving the transmitted signal do not hear the audio content being provided by the first transducer coupled to the communication device.
14. The method of claim 11 further including the steps:
enabling an adaptive filter to adaptively filter the output signal for providing the modified output signal for transmission by the communication device when the voice activity level of the spoken voice of the user of the communication device is above a predetermined threshold;
providing the audio content as a reference signal for the adaptive filter;
providing a signal that includes the spoken voice of the user of the communication device and the audio content to the adaptive filter; and
subtracting the audio content from the signal using the adaptive filter to generate the modified output signal.