Abstract:
A method of operating a hearing assistance system that includes a binaural hearing device with first and second earpieces, each earpiece adapted to be worn over, on or in one ear. Each earpiece has an electroacoustic transducer that converts an input electrical audio signal for the ear into sound, and at least one microphone that converts sound into an electrical microphone output signal. The hearing assistance system is adapted to process microphone output signals from both earpieces to create the electrical audio signals that are used to drive the transducers of both earpieces. A situation in which one of the earpieces is not over, on or in an ear is detected, and in response the processing of at least one of the microphone output signals that creates the audio signals is modified.

Description:
BACKGROUND 
       [0001]    This disclosure relates to a hearing assistance system. 
         [0002]    Some binaural hearing assistance systems have two earbuds (or other types of earpieces that deliver sound to an ear), one for each ear. Each earpiece has one or more microphones. The microphones on both ears can be used together to increase the performance of the system, for example by binaural beamforming. Some users, however, prefer a single-ear device due to reduced stigma, ease of conveying social availability, having only a unilateral hearing loss, or other motivation. Users who prefer to use only one earpiece in a system where two earpieces are in some manner connected, be that physically with a wire or through wireless communication, may leave the other earpiece to rest against the neck or shoulder, or hidden under a shirt, or placed in a pocket, or placed in a storage case, or “parked” to neckware that is part of the system via a magnet, mechanical connection, or other means. Doing so, however, creates problems for binaural beamforming and other processing which utilize microphones on both sides of the head to create the output signal for each ear. Namely, the “dropped” earpiece and its microphones are no longer pointing in the “look” direction of the array, and they are no longer in the same plane or position relative to the other-side microphones. These two issues negatively impact performance of the array for the ear audio signal into the assisted ear. Additionally, microphones of the “dropped” earpiece may be in close contact to surrounding objects (e.g., shirt, necklace), and interference with those objects could cause significant and objectionable noise to be generated in the assisted ear. Further, when an earbud is removed from the ear there is increased acoustic coupling between the driver output and external microphone input, which can cause objectionable audible oscillation due to acoustic feedback. Other algorithms, such as binaural steady-state noise suppressors, may also perform in a sub-optimal manner. 
       SUMMARY 
       [0003]    The above problems can be resolved or ameliorated by detecting when an earbud or another type of earpiece of a binaural hearing assistance system is not in, on or over an ear, and in response modifying the processing of the microphone signals that are involved in creating the audio signals. The detection drives a mode change in the beamforming (directional processing) and/or other system algorithms to improve performance for the single-ear assistance case. Improved performance in the single ear case could, for example, include changing the array design to a single-sided beamformer on the non-dropped side, changing the array design such that two-sided arraying is still used but only at frequencies in which the dropped microphones aid performance for the aided ear, modifying a binaural noise reduction algorithm to use data from the dropped ear in a different manner, turning off the output to the dropped earpiece driver so as to stop feedback oscillation, and turning off the microphone bias on the dropped earpiece, if the microphone is not needed, so as to decrease power consumption. Other benefits are possible. 
         [0004]    All examples and features mentioned below can be combined in any technically possible way. 
         [0005]    In one aspect, a method of operating a hearing assistance system that comprises a binaural hearing device that has first and second earpieces, each earpiece adapted to be worn over, on or in one ear, each earpiece comprising an electroacoustic transducer that converts an input electrical audio signal for the ear into sound, and at least one microphone that converts sound into an electrical microphone output signal, where the hearing assistance system is adapted to process microphone output signals from both earpieces to create the electrical audio signals that are used to drive the transducers of both earpieces, includes detecting when one of the first and second earpieces is not over, on or in an ear and in response modifying the processing of at least one of the microphone output signals that creates the audio signals. 
         [0006]    Embodiments may include one of the following features, or any combination thereof. Modifying the processing of at least one of the microphone output signals that creates the audio signals may comprise processing only the microphone output signal from the other of the first and second earpieces to create the audio signal for the transducer of the other earpiece. Modifying the processing of at least one of the microphone output signals that creates the audio signals may comprise processing microphone output signals from both earpieces to create the electrical audio signals that are used to drive the transducers of both earpieces, but only up to a cutoff frequency. Modifying the processing of at least one of the microphone output signals that creates the audio signals may comprise modifying the processing of the microphone output signals from the earpiece that is not over, on or in an ear. In this case the method may further comprise maintaining the processing of the microphone output signals from the other earpiece. Modifying the processing of the microphone output signals from the earpiece that is not over, on or in an ear may comprise band limiting the microphone output signals from the earpiece that is not over, on or in an ear. 
         [0007]    Embodiments may include one of the following features, or any combination thereof. The method may further comprise, in response to detecting when an earpiece is not over, on or in an ear, turning off or reducing the output level of the transducer of the earpiece that is not over, on or in an ear. The earpiece microphones may detect sound external to the earpieces. Modifying the processing of at least one of the microphone output signals that creates the audio signals may comprise turning off a microphone bias of a microphone of the earpiece that is not over, on or in an ear. Modifying the processing of at least one of the microphone output signals that creates the audio signals may comprise modifying a binaural steady-state noise reduction algorithm, which may comprise changing a configuration of internal parameters within the steady-state noise reduction algorithm. 
         [0008]    In another aspect, a method of operating a hearing assistance system that comprises a binaural hearing device that has first and second earpieces, each earpiece adapted to be worn over, on or in one ear, each earpiece comprising an electroacoustic transducer that converts an input electrical audio signal for the ear into sound, and at least one microphone that converts sound into an electrical microphone output signal, where the hearing assistance system is adapted to process microphone output signals from both earpieces to create the electrical audio signals that are used to drive the transducers of both earpieces, includes detecting when one of the first and second earpieces is not over, on or in an ear and in response modifying a processing of the hearing assistance system that uses microphone output signals from both earpieces. 
         [0009]    Embodiments may include one of the following features, or any combination thereof. Modifying a processing of the hearing assistance system that uses microphone output signals from both earpieces may comprise processing only the microphone output signal from the other of the first and second earpieces to create the audio signal for the transducer of the other earpiece. Modifying a processing of the hearing assistance system that uses microphone output signals from both earpieces may comprise processing microphone output signals from both earpieces to create the electrical audio signals that are used to drive the transducers of both earpieces, but only up to a cutoff frequency. Modifying a processing of the hearing assistance system that uses microphone output signals from both earpieces may comprise modifying the processing of the microphone output signals from the earpiece that is not over, on or in an ear while maintaining the processing of the microphone output signals from the other earpiece. Modifying the processing of the microphone output signals from the earpiece that is not over, on or in an ear may comprise band limiting the microphone output signals from the earpiece that is not over, on or in an ear. 
         [0010]    Embodiments may include one of the following features, or any combination thereof. The method may further comprise, in response to detecting when an earpiece is not over, on or in an ear, turning off or reducing the output level of the transducer of the earpiece that is not over, on or in an ear. Modifying a processing of the hearing assistance system that uses microphone output signals from both earpieces may comprise changing a configuration of internal parameters within a binaural steady-state noise reduction algorithm. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is schematic diagram of a person using a binaural hearing assistance system. 
           [0012]      FIG. 2  is a schematic block diagram of a binaural hearing assistance system. 
           [0013]      FIG. 3  is a schematic block diagram of an earbud for a binaural hearing assistance system. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Binaural hearing assistance devices have two earpieces, one for each ear. Some such devices use binaural microphone algorithms such as beamforming to improve performance. Binaural microphone algorithms are discussed in U.S. patent application Ser. No. 14/618,889, entitled “Conversation Assistance System,” the disclosure of which is incorporated herein by reference. At times when only one earpiece is in an ear the input to binaural microphone algorithms (e.g., beamforming for directional processing) changes, since the microphones of the earpiece that is not in an ear are no longer pointing the same direction as the others (e.g., in the look direction of a binaural microphone array), and they are no longer in the same plane or position relative to the microphones of the earpiece that is in an ear. Any processing that uses microphones from both sides for the earpiece that is in an ear suffers as a result. 
         [0015]    A binaural hearing assistance system with two earpieces can be operated so as to lessen the impacts associated with single ear operation. In part, this result is accomplished by, in response to detecting when one of the earpieces is not over, on or in an ear, modifying the processing of at least one of the microphone output signals that creates the audio signals. For example, the system can be modified so that only the microphone output signals from the earpiece in an ear are used to create the audio signal for the transducer of the earpiece that is in an ear. Or, the microphones from both earpieces can be used, but only up to a cutoff frequency. Another option is to modify the processing of the microphone output signals from the dropped earpiece such as by band-limiting them. Oscillation can be reduced or eliminated by either reducing the output level or turning off the transducer of the dropped earpiece that is not over, on or in an ear. 
         [0016]    There are many ways by which to detect when an earpiece is not on, over or in an ear, i.e., it has been “dropped.” Non-limiting examples include earpiece parking detectors that detect proximity of a parked earpiece to a charging case or neckware such as with a hall effect sensor, switch-based sensing triggered by mechanical capture or electrical contact of the parked earpiece with a charging case or neckware, and acoustic-based sensing of the earpiece no longer placed in the ear, to name a few. However, this disclosure is not limited by the manner in which a dropped earpiece is detected. Once a dropped earpiece has been detected, the system enables one or more changes to its operation that will reduce the negative effects of the dropped earpiece. System changes can be reversed when the dropped earpiece is placed back in, on or over an ear. 
         [0017]    Binaural hearing assistance system  10 ,  FIG. 1 , includes an audio source  12  that is operatively connected e.g., with wire  14 , or wirelessly (for example using Bluetooth technology) to left earpiece  16  that is designed to be used in, on or over left ear  17 , and right earpiece  18  that is designed to be used in, on or over right ear  19 . In this non-limiting example earpiece  18  (which is illustrated as an earbud) has been removed from ear  19  and has been coupled (“parked”) to neckwear  20  that is designed to hold an earpiece that is not in use. Neckwear  20  may include some mechanism or device that detects a dropped earpiece (such as but not limited to the mechanism used in the “Tone”™ line of wireless headsets available from LG Electronics USA), or as described above system  10  may include or be used with another means of detecting when an earpiece is not in, on or over an ear. Detection of a dropped earpiece drives a mode change in the system such as alternate beamforming modes and other algorithm modes or tunings to improve the performance of the system. 
         [0018]    The electrical and electronic components of an exemplary binaural hearing assistance system  30  are schematically depicted in  FIG. 2 . Audio source  12  in this case includes Bluetooth radio  32  that has antenna  34 . Audio source signals are provided to left and right digital signal processors (DSPs)  36  and  42 , whose digital outputs are provided to left and right codecs  38  and  44 . The resulting analog audio signals are provided to left and right earpieces (earbuds)  16  and  18 , which have drivers  45  and  47  and microphone(s)  46  and  48 , respectively. In some cases, the microphones alone are used to provide signals for output, perhaps processed by DSPs  36  and  42 , i.e., like a conventional hearing aid, and no additional source is provided. 
         [0019]    An exemplary earbud  50  is shown in highly schematic block diagram form in  FIG. 3 . Earbud  50  is held in ear canal  48 . Effective acoustic baffle  60  separates the outside environment from driver  52  and feedback microphone  54 , which is used for feedback-based active noise reduction. Acoustic baffle  60  (shown schematically in  FIG. 3 ) is typically effectively created by the combination of an ear tip, transducer, and mechanical enclosure combining those elements. Feed forward and array microphones  56  are used for feed-forward active noise cancellation and can be placed at the ear, proximate to the ear in the concha, or proximate, ideally above, the pinna. Combinations of feed forward and array microphones  56  are also used for environmental sound detection including as inputs to directional processing, dynamic range compression, and other hearing-related algorithms. 
         [0020]    The components of the present binaural hearing assistance system are known in the art. The system is operated in accordance with the present disclosure so as to lessen the impacts associated with single-ear operation. These operational advantages are mostly accomplished via DSPs  36  and  42  ( FIG. 2 ), which can be operated in a manner such that when a dropped earpiece is detected (e.g., using another component such as a switch (not shown) that is part of source  12 , or using signals received by source  12  from one or more earpiece microphones), the processing of the output signals of one or more of microphones  54  and  56  that are used to create the audio signals that are provided to one or both of earpieces  16  and  18 , is modified. In some cases the DSPs are controlled by a microprocessor (not shown). 
         [0021]    In one example, the DSP operation can be modified for single-ear use so that the system operates as a single-sided beamformer on the non-dropped side, which can be accomplished by using only the microphone output signals from the earpiece in use (i.e., the earpiece that is located in, on or over an ear) to create the audio signal for the transducer of that earpiece. In another example the microphones from both earpieces can be used to create both audio signals (i.e., binaural beamforming operation remains), but only up to a cutoff frequency. The cutoff frequency can be selected such that the microphones of the dropped earpiece aid performance for the non-dropped earpiece. As one non-limiting example a cutoff frequency could be around 500 Hz; low frequencies that are still used in binaural beamforming in this case are helpful for providing location cues even though the microphones of the earpiece that is not in an ear are no longer pointing in the look direction of the microphone array, and they are no longer in the same plane or position relative to the microphones of the earpiece that is in an ear. 
         [0022]    In another example of modified single-ear operation the processing of the microphone output signals from the dropped earpiece is modified in another way, such as by band limiting (or eliminating) the signals from the microphones of the dropped earpiece. Such modification could be applied to a binaural steady-state noise reduction algorithm, for example. In this example, configuration of internal parameters within the steady-state noise reduction algorithm could also be changed. In cases where microphone(s) are not used, the microphone bias (for microphones that need it) can be turned off, to reduce power consumption. 
         [0023]    When acoustic baffle  60  no longer sufficiently decouples microphones  56  from driver  52 , a potential feedback loop is created, by which the system can oscillate and create audible feedback signals. Such feedback signals can be reduced in amplitude (e.g., such that they are no longer audible to a person) or eliminated by either reducing the output level until the microphone no longer detects it and oscillation stops, or turning off the driver when the earpiece is dropped. Another approach would be to notch-filter the microphone around the frequency of the oscillation. 
         [0024]    Elements of figures are shown and described as discrete elements in a block diagram. These may be implemented as one or more of analog circuitry or digital circuitry. Alternatively, or additionally, they may be implemented with one or more microprocessors executing software instructions. The software instructions can include digital signal processing instructions. Operations may be performed by analog circuitry or by a microprocessor executing software that performs the equivalent of the analog operation. Signal lines may be implemented as discrete analog or digital signal lines, as a discrete digital signal line with appropriate signal processing that is able to process separate signals, and/or as elements of a wireless communication system. 
         [0025]    When processes are represented or implied in the block diagram, the steps may be performed by one element or a plurality of elements. The steps may be performed together or at different times. The elements that perform the activities may be physically the same or proximate one another, or may be physically separate. One element may perform the actions of more than one block. Audio signals may be encoded or not, and may be transmitted in either digital or analog form. Conventional audio signal processing equipment and operations are in some cases omitted from the drawing. 
         [0026]    Embodiments of the systems and methods described above comprise computer components and computer-implemented steps that will be apparent to those skilled in the art. For example, it should be understood by one of skill in the art that the computer-implemented steps may be stored as computer-executable instructions on a computer-readable medium such as, for example, floppy disks, hard disks, optical disks, Flash ROMS, nonvolatile ROM, and RAM. Furthermore, it should be understood by one of skill in the art that the computer-executable instructions may be executed on a variety of processors such as, for example, microprocessors, digital signal processors, gate arrays, etc. For ease of exposition, not every step or element of the systems and methods described above is described herein as part of a computer system, but those skilled in the art will recognize that each step or element may have a corresponding computer system or software component. Such computer system and/or software components are therefore enabled by describing their corresponding steps or elements (that is, their functionality), and are within the scope of the disclosure. 
         [0027]    A number of implementations have been described. Nevertheless, it will be understood that additional modifications may be made without departing from the scope of the inventive concepts described herein, and, accordingly, other embodiments are within the scope of the following claims.