The technology described in this patent application relates generally to the field of hearing instruments. More particularly, the application describes a system and method for detecting the insertion and removal of a hearing instrument from the ear canal. This technology may have utility in any hearing aid, listening device or headset having an output that is delivered into a sealed ear (circumaural earcup) or ear canal (insert earphone, hearing aid, etc.).
When a hearing instrument is removed from the ear canal, the increased acoustic coupling between the receiver (loudspeaker) and the microphone can cause howling or feedback. Furthermore, the device is typically not in use when removed. Therefore, knowledge that the device has been removed can be used to lower the acoustical gain to prevent feedback and/or to reduce power consumption by switching the unit off or entering a low-power standby mode.
Conversely, when the unit is re-inserted, knowledge that the device has been inserted can be used to automatically restore gain and power. In a communications headset, this information can be used to automatically answer an incoming call or to terminate a completed call.
Additionally, a hearing instrument is designed to have an acceptable acoustic response when sealed with a user's ear. However, when initially fitted or when in later use, the hearing instrument may not form a proper seal. Accordingly, an audiologist or user may need to determine whether the hearing instrument has formed a proper seal.
A hearing instrument system for detecting the insertion or removal of a hearing instrument into a space comprises first and second acoustic transducers, first and second level detection circuitry, and signal processing circuitry. The first acoustic transducer is configured to receive a first electrical signal and in response radiate acoustic energy, and the second acoustic transducer is configured to receive radiated acoustic energy and in response generate a second electrical signal. The first level detection circuitry is operable to receive the first electrical signal and generate a first intensity signal, and the second level detection circuitry is operable to receive the second electrical signal and generate a second intensity signal. The signal processing circuitry is operable to receive the first and second intensity signals and compare the first and second intensity signals and determine whether the hearing instrument system is inserted into the space or removed from the space based on the comparison.
An electronically-implemented method of determining whether a hearing instrument is removed from or inserted into a space comprises monitoring the level of acoustic energy radiated by the hearing instrument, monitoring the level of acoustic energy received by the hearing instrument in response to the acoustic energy radiated by the hearing instrument, comparing the level of acoustic energy radiated by the hearing instrument to the level of acoustic energy received by the hearing instrument in response to the acoustic energy radiated by the hearing instrument, and determining whether the hearing instrument is inserted into the space or removed from the space based on the comparison.
A method of determining whether a hearing instrument is removed from or inserted into a space comprises monitoring the level of acoustic energy radiated by the hearing instrument over a frequency band; monitoring the level of acoustic energy received by the hearing instrument over the frequency band in response to the acoustic energy radiated by the hearing instrument when the hearing instrument is inserted into the space; comparing the level of acoustic energy radiated by the hearing instrument to the level of acoustic energy received by the hearing instrument over the frequency band when the hearing instrument is inserted into the space to obtain first comparison data; monitoring the level of acoustic energy received by the hearing instrument over the frequency band in response to the acoustic energy radiated *y the hearing instrument when the hearing instrument is removed from the space; comparing the level of acoustic energy radiated by the hearing instrument to the level of acoustic energy received by the hearing instrument over the frequency band when the hearing instrument is removed from the space to obtain second comparison data; and identifying stable band differentials between the first comparison data and the second comparison data for the monitoring insertion and removal events.
A system for detecting the insertion and removal of a hearing instrument (e.g., a hearing aid, a headset, or other type of hearing instrument) from the ear canal includes a loudspeaker driving into a sealed acoustic cavity, a microphone that is acoustically coupled to this sealed cavity, and signal processing circuitry used to determine if the cavity is sealed or not. The acoustic data associated with the loudspeaker and microphone is processed by the signal processing circuitry to automatically control the power consumption or acoustical gain of the hearing instrument.
In a hearing aid, gain reduction can be used to prevent howling due to feedback when the device is not properly seated in the ear canal, or when the device is removed from the ear canal or loose in the ear canal. This is a convenience feature to the user since the presence of howling is often a nuisance. In addition, power consumption can be reduced because many processing features may be deactivated when the device is outside the ear canal.
In a communications headset, the automatic detection of an insertion can be used to provide a hands-free method of answering an incoming call and the automatic detection of a removal can be used to put the headset into a standby or low-power mode. Both of these actions help eliminate acoustic feedback and extend battery life.
By placing a pressure-sensitive microphone inside the sealed acoustic cavity, the frequency response can be measured as the loudspeaker is operating. One such exemplary circuit is depicted in
The microphone 30 is coupled to a second level detection circuitry 32 that is operable to receive the second electrical signal and generate a second intensity signal IO. In one embodiment, the second level detection circuitry 32 comprises a bandpass filter 34 and a level detector 36.
The bandpass filters 24 and 34 limit the frequency range of the detection circuitry 22 and 32 to those frequencies where a substantial difference in level is expected. A band in which a substantial difference in level is expected may be referred to as a stable band differential β. The magnitude of the difference is such that minor adjustments or changes in the monitored levels should not cause false indications of an insertion or removal.
For example, for the response depicted in
In the embodiments shown, the level detectors 26 and 36 estimate the RMS levels simultaneously present at the input to the loudspeaker 20 and the output of the microphone 30. Other averaging estimations may also be used instead of RMS level averages.
The expected ratio of the signal levels ID and IO under the sealed and unsealed conditions is derived from knowledge of the electro-acoustic transfer function from the loudspeaker 20 to the microphone 30 under the various operating conditions. For example, data related to the signal levels ID and IO may be obtained by monitoring the ID and IO intensity levels during several frequency sweeps of the electrical signal driving the loudspeaker 20 when the hearing instrument 10 is inserted into a cavity and when the hearing instrument 10 is removed from the cavity. Alternatively, the data can be either measured using a system calibration, or derived from models of the transducers, amplifiers and acoustic cavity, or gathered in an adaptive fashion by a processing circuitry that continuously monitors the signal levels.
The data related to the signal levels ID and IO may then be processed to obtain the response ratios of
Upon determining whether the hearing instrument 10 is removed or inserted into a space, correspond gain control signals CG and/or power control signals CP can be generated. The gain controls signal CG may be used to reduce the gain on an output amplifier driving the loudspeaker 20, or reduce the gain on a microphone receiving an input signal to generate a drive signal for the loudspeaker 20 upon detecting that the hearing instrument 10 has been removed from the space, thus preventing howling. Additionally, upon detecting that the hearing instrument 10 has been inserted into the space, the control signal CG may be used to increase the hearing instrument gain to a normal operating parameter. The power control signal CP may be used to deactivate the hearing instrument 10 after the hearing instrument 10 has been removed from the space and after a period of time has elapsed during which the hearing instrument 10 has not been reinserted into the space. Accordingly, automatic gain reduction for the hearing instrument 10 removed from the ear and automatic power reduction for hearing instrument 10 removed from the ear may be realized.
Other functions may also be supported by the detection of the insertion or removal of the hearing instrument 10. For example, automatic calibration checks may be triggered during each insertion of the hearing instrument 10, or may be triggered after a given number of insertions and removals. Adaptive identification of on and off signals levels may also be facilitated to eliminate system calibration.
The signal processing circuitry 40 may be configured to implement one or more processing methods to control the hearing instrument 10 based on the detection of an insertion or removal of the hearing instrument 10 into a space.
If the comparison of step 104 indicates that the hearing instrument has been removed from the space, then in step 108 the gain of the hearing instrument is reduced, and the process returns to step 102. Conversely, if the comparison of step 104 indicates that the hearing instrument has been inserted into the space, then in step 110 the gain of the hearing instrument is increased and the process returns to step 102.
In the embodiment shown, the comparison step is based on a ratio of the intensity levels ID and IO. In one embodiment, the comparison compares the ratio from a previously monitored ratio, and if the compared ratios have changed substantially, then a removal or insertion event has occurred. By way of example, consider the graph of
In another embodiment, the ratio of the intensity levels ID and IO is compared to a threshold. For example, in the graph of
A hysteresis may also be used in the comparison to prevent cycling of gain reduction and increase. For example, if the ratio of the intensity levels ID and IO fall below −13 dB, indicating that the hearing instrument is removed from the space, the signal processing circuitry may then be configured to detect an insertion only if the ratios of the intensity levels ID and IO thereafter rise above −10 dB. Similarly, if the ratio of the intensity levels ID and IO rise above −13 dB, indicating that the hearing instrument is inserted the space, the signal processing circuitry may then be configured to detect a removal only if the ratios of the intensity levels ID and IO thereafter fall below −16 dB. Other hysteresis levels and processes may also be used.
In step 122, the signal processing circuitry monitors the intensity levels ID and IO, and the monitored levels are compared in step 124. In step 126, the signal processing circuitry determines whether the comparison of step 124 indicates that the hearing instrument has been removed, inserted, or if neither of these events have occurred. If neither of these events have occurred, indicating that the hearing instrument has not been removed if it is presently inserted into the space, or that the hearing instrument has not been inserted if it is presently removed from the space, then the process returns to step 122.
If the comparison of step 124 indicates that the hearing instrument has been removed from the space, then in step 128 the gain of the hearing instrument is reduced, and the process returns to step 122. Conversely, if the comparison of step 124 indicates that the hearing instrument has been inserted into the space, then in step 130 the signal processing circuitry waits for an insertion time delay ΔtI, and then in step 132 the gain of the hearing instrument is increased. The process then returns to step 122.
In step 142, signal processing circuitry monitors the intensity levels ID and IO, and the monitored levels are compared in step 144. In step 146, the signal processing circuitry determines whether the comparison of step 144 indicates that the hearing instrument has been removed, inserted, or if neither of these events have occurred. If neither of these events have occurred, indicating that the hearing instrument has not been removed if it is presently inserted into the space, or that the hearing instrument has not been inserted if it is presently removed from the space, then the process returns to step 142.
If the comparison of step 144 indicates that the hearing instrument has been removed from the space, then the processing circuitry waits for a removal time delay ΔtR in step 148, and then monitors the intensity levels ID and IO in step 150, and compares the monitored levels in step 152. In step 154, the processing circuitry determines if the comparison indicates that the hearing instrument is still removed from the space. If so, then the gain is reduced in step 156, and the process returns to step 142. If the processing circuitry, however, determines that the comparison indicates that the hearing instrument is not removed from the space, then the gain remains unchanged and the process returns to step 142.
Returning to step 146, if the comparison of step 144 indicates that the hearing instrument has been inserted into the space, then the processing circuitry waits for an insertion time delay ΔtI in step 158, and then monitors the intensity levels ID and IO in step 160, and compares the monitored levels in step 162. In step 164, the processing circuitry determines if the comparison indicates that the hearing instrument is still inserted into the space. If so, then the gain is increased in step 166, and the process returns to step 142. If, however, the processing circuitry determines that the comparison indicates that the hearing instrument is not inserted the space, then the gain remains unchanged and the process returns to step 142.
Conversely, upon a negative determination in step 176, the processing circuitry determines if a removed clock timeout has occurred in step 180. If a removed clock timeout has not occurred, then the process returns to step 176. If a removed clock timeout has occurred, however, then the hearing instrument is shut down in step 182 to conserve battery power.
Other methods of conserving battery power may also be used. For example, instead of reducing gain upon the detection of a removal event, the hearing instrument may automatically power down upon such detection. Alternatively, if the monitoring band is in the low frequency range, such as the band β shown in
While the frequency bands to be monitored may be selected during a configuration of the hearing instrument, such as when an audiologist first fits a user with an hearing aid, the processing circuitry may also be configured to automatically adjust or automatically select the frequency bands to be monitored.
In step 192, the signal processing circuitry monitors the intensity levels IO and ID in an inserted state over a wide frequency band, and stores the averaged inserted IO/ID ratio data.
In step 196, the signal processing circuitry identifies stable band differentials between the averaged inserted IO/ID ratio data and the averaged removed IO/ID ratio data. A stable band differential is a region in which there is a substantial difference in ratio levels. For example, the data of
The systems and methods herein may also be used to detect or measure how well a hearing instrument forms a seal with a user's ear. The seal may be measured by monitoring the frequency response ratio of IO and ID and comparing the monitored ratio to an ideal ratio or a previously measured known ratio. For example, during the fitting of a hearing instrument, and audiologist may obtain a mold of a user's ear canal and the hearing instrument may be constructed to according to the mold. Upon receiving the completed hearing instrument, the audiologist may test the hearing instrument in a controlled setting, such as an adjustable test mold, to obtain an ideal, or near ideal, frequency response ratio of IO and ID of the hearing instrument. This controlled frequency response ratio of IO and ID may then be used to establish a baseline by which to measure the actual fit within the user's ear canal.
For example,
In one embodiment, the comparison is made over a low frequency band β3. The “sealed actual response” is an example actual response within a threshold level of the baseline response over the band β3 and indicates a well-sealed hearing instrument. Conversely, the “unsealed actual response” is an example actual response this is not within the threshold level of the baseline response over the band β3 and indicates a poorly-sealed hearing instrument. An unsealed actual response may be due to the hearing instrument needing adjustment in the ear canal to close the seal, or may be due to the hearing instrument dimensions not matching the user's ear canal so that a seal cannot be obtained. In the latter case, the audiologist may need to take another mold of the ear canal and have another hearing instrument constructed.
In the embodiment shown, the determination of a sealed response or an unsealed response is based on the actual response being within a threshold intensity level ΔdB of the baseline response, e.g., −3 dB. If the response is not within the threshold ΔdB over the entire band β3, or a substantial portion of the band β3, then the hearing instrument is determined to be unsealed. Conversely, if the response is within the threshold ΔdB over the entire band β3, or a substantial portion of the band β3, then the hearing instrument is determined to be sealed. While the threshold ΔdB has been illustrated as constant threshold over the band β3, the threshold β3 may also vary over the band ΔdB, e.g., ΔdB may be −6 dB at the lower cutoff frequency, and may be −3 dB at the upper cutoff frequency.
In another embodiment, the system and method described with respect to
In another embodiment, the system and method described with respect to
While the system and methods of
The embodiments described herein are examples of structures, systems or methods having elements corresponding to the elements of the invention recited in the claims. This written description may enable those of ordinary skill in the art to make and use embodiments having alternative elements that likewise correspond to the elements of the invention recited in the claims. The intended scope of the invention thus includes other structures, systems or methods that do not differ from the literal language of the claims, and further includes other structures, systems or methods with insubstantial differences from the literal language of the claims.
This patent application claims the benefit of priority to U.S. Provisional Application Ser. No. 60/459,565, filed on Apr. 1, 2003, the entire disclosure of which is incorporated herein by reference.
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