Processing signals representative of sound based on the identity of an input element

Systems and techniques for processing signals representative of sound for conveyance to the auditory system of a subject based on the identity of an input device. In one implementation, a method includes identifying an input element to an audiological system that conveys sound information directly to a subject's auditory system, automatically setting parameters for processing the signal based on the identity of the input element, and processing the signal in accordance with the processing parameters. The input element is configured to generate a signal representative of sound.

BACKGROUND

This disclosure relates to processing signals representative of sound for conveyance directly to the auditory system of a subject based on the identity of an input device.

Humans have traditionally perceived sound using the physiological auditory system. This perception of sound can now be supplemented by man-made audiological systems that convey sound information directly to a subject through components of the auditory system. Such audiological systems convey sound information directly to a subject's auditory system by stimulating the subject's auditory system without significant dissemination of sound waves into the surroundings. Audiological systems include hearing aids, cochlear implants, and other devices that include a microphone or other input element.

When such input elements are stimulated, they produce signals representative of sound. Such signals often are not immediately compatible with the auditory system and must be processed so that the sound information in the signal can be conveyed to the auditory system.

Such sound processing may include any of a number of different changes to the signal, including amplification, filtering, mixing, and encoding changes. The nature and extent of the changes can be based on factors such as the nature of the sound represented in the signal, the state of the auditory system, the nature of the interface between the auditory system and the audiological system, the characteristics of the input element, and the like.

SUMMARY

The inventors recognized that the processing of signals representative of sound for conveyance directly to the auditory system of a subject can be changed automatically (i.e., without human intervention) depending on the identity of an active sound input element. For example, in one implementation, a method includes identifying an input element to an audiological system that conveys sound information directly to a subject's auditory system, automatically setting parameters for processing a signal representative of sound based on the identity of the input element, and processing the signal in accordance with the set processing parameters. The input element is configured to generate the signal representative of sound. The method is implemented by a machine.

This and other implementations can include one or more of the following features. The input element can be identified by recognizing an electrical characteristic of the input device. For example, an electrical response of the input device can be sampled to recognize the electrical characteristic. The sample of the electrical response can be compared to a library of expected responses. As another example, at least one of a power-on transient, a power-off transient, a characteristic impedance of the input element, and a unique identifier of the input element can be recognized to recognize the electrical characteristic.

Processing the signal in accordance with the processing parameters can include mixing the signal with a second signal representative of sound. The second signal can be generated by a second input element to the audiological system. The input element can be uniquely identified or the input element can be identified as a member of a class of input elements. For example, the input element can be identified as an audio frequency induction loop receiver, as a low source impedance signal generator (such as a CD/MP3 player), or as a direct input, pressure-sensitive element (such as a microphone).

The method can also include conveying the processed signal directly to the subject's auditory system. Interchangeable input element can be identified. Input elements can be identified based on a response of the input element to one or more of a power-on event and a power-off event. The identification of the input element can be in response to a triggering event such as a prompt by a user. Processing the signal in accordance with the processing parameters can include processing the signal for direct electrical stimulation of a cochlea in the subject's auditory system.

In another implementation, an apparatus includes an audiological system configured to convey sound information to a subject's auditory system. The audiological system includes an input element configured to generate a signal representative of sound, a library of associations of processing parameters, and a selection processor configured to automatically select an association of processing parameters based on an identity of the input element. The associations of processing parameters each include processing parameters that are coordinated to improve processing of certain classes of signals representative of sound.

This and other implementations can include one or more of the following features. The library of associations can include a program category identifier that identifies certain associations in the library as belonging to a particular program category. The audiological system can include a user selection input configured to receive a user selection of a program category desired by a user or a second input element configured to generate a signal representative of sound.

The associations can be programs of processing parameters. The parameters can be coordinated to improve processing of signals representative of sound from certain classes of input devices. A first program can include processing parameters coordinated to improve processing of signals representative of sound from an audio frequency induction loop receiver, from a low source impedance signal generator, or from a direct input, pressure-sensitive element.

The audiological system can include a portion dimensioned to be borne by a subject. The borne portion can include a memory device that stores the library of associations. The audiological system can include a device configured to directly stimulate a subject's nerve cells, such as a subject's cochlear nerve cells.

In another implementation, an apparatus includes an audiological system configured to convey sound information to a subject's auditory system. The system includes a processor having inputs to receive a first signal representative of sound generated by a first input element and a second signal representative of sound generated by a second input element. The processor includes identification logic to identify at least one of the first input element and the second input element, setting logic to set processing parameters based on the identification by the identification logic, and signal processing logic to process at least one of the first signal and the second signal in accordance with the processing parameters.

This and other implementations can include one or more of the following features. The processor can include identification logic to identify a class of at least one of the first input element and the second input element. For example, the identification logic can compare a characteristic of the at least one of the first input element and the second input element with expected values from different classes of input elements.

The audiological system can also include a transient sampling device arranged to sample at least one of a power-on transient and a power-off transient and to provide the sample to the processor. The audiological system can include a device configured to directly stimulate a subject's nerve cells, such as a subject's cochlear nerve cells.

In another implementation, an audiological system can include an implanted portion and an unimplanted portion. The implanted portion can include a receiver configured to receive information, and electrodes arranged to convey the received information directly to nerve cells in a subject's auditory system. The unimplanted portion can include a first input element configured to generate a first signal representative of sound, a second input element configured to generate a second signal representative of sound, a processor configured to identify at least one of the first input element and the second input element and process at least one of the first signal and the second signal in accordance with the identification, and a transmitter configured to transmit the information to the receiver of the implanted portion, the transmitted information reflecting the processing by the processor.

These and other implementations can be implemented to realize one or more of the following advantages. The signature of an auxiliary input to the front end of a sound processor can be automatically sensed. The signature can be used to identify the class of accessory or input device connected to the processor, and signal processing can be adjusted in light of the identified class.

The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description, the drawings, and the claims.

DETAILED DESCRIPTION

FIG. 1shows an audiological system105that conveys sound information110directly to a subject's auditory system115. Audiological system105includes input elements120,125, a processor130, and an interface with the auditory system135. Input elements120,125are devices that generate signals representative of sound. Input elements120,125can be direct input devices in that they transduce sound waves directly to generate a signal representative of sound (e.g., pressure-sensitive elements such as microphones). Input elements120,125can alternatively be indirect input elements in that they respond to something other than sound waves to generate a signal representative of sound. For example, input elements120,125can receive an audio component of a television or radio signal to generate a signal representative of sound. Thus, input elements120,125can be, e.g., a compact disk player or an MP3 player or other player of stored or streaming digital data. Input elements120,125output the signals representative of sound to processor130.

Processor130receives signals representative of sound from input elements120,125. Processor130is a device that processes information. For example, processor130processes the signals generated by input elements120,125for conveyance to the auditory system in accordance with logic embodied in hardware and/or software. Processor130can include analog and/or digital electronic circuitry, or combinations thereof. Processor130can also include one or more data storage devices that store logic and/or parameters for the processing of signals. Processor130outputs the processed sound signals to auditory system interface135.

Auditory system interface135receives the processed sound signals from processor130. Auditory system interface135is a device that conveys the processed sound signals as information110directly to the subject's auditory system115. Information110is compatible with the subject's auditory system115. In a typical human subject, auditory system115includes an eardrum140, ossicles145, cochlea150, and auditory nerve155, along with portions of the brain that process sound information (not shown). Auditory system interface135can convey information110directly to these or other portions of auditory system115. For example, auditory system interface135can be a speaker in a hearing aid that generates sound waves of sufficient amplitude to mechanically stimulate auditory system115. As another example, auditory system interface135can be an electrode array that electrically stimulates nerve cells in a portion of auditory system115. The conveyed information110includes at least a portion of the information processed by processor130.

FIG. 2shows another audiological system205that conveys sound information110directly to a subject's auditory system115. Audiological system205is designed to convey sound information by directly stimulating nerve cells in cochlea150of a subject's auditory system. Audiological system205can be dimensioned to be borne by a subject.

Audiological system205includes an implanted portion210and an unimplanted portion215. Implanted portion210acts as interface135in stimulating cochlea150to convey information110to the subject. Implanted portion210includes a receiver220, a lead225, and a collection of electrode contacts230. Receiver220is a device that receives power and information235from outside the body. For example, receiver220can include a metal coil sheathed in a biocompatible cover. Lead225conveys power and information235received by receiver220to electrode contacts230. Electrode contacts230directly stimulate nerve cells in cochlea150in accordance with the information235received by receiver220. For example, individual electrode contacts230can change the local electrical potential, inject current, and/or otherwise stimulate the depolarization of selected nerve cells in cochlea150to convey information110to a subject. In one implementation, implanted portion210can be the HiRes™ 90K Implant from Advanced Bionics Corporation (Sylmar, Calif.).

Unimplanted portion215includes a transmitter240and a behind-the-ear (BTE) unit245. Transmitter240is a device for conveying power and information235to receiver220from outside the body. For example, transmitter240can include a metal coil sheathed in a cover.

Behind-the-ear unit245can be dimensioned to be mounted and supported on a subject's ear. Behind-the-ear unit245includes a power supply250, an input element housing255, and a processor housing260. Power supply250can be a battery or other source of energy. Power supply250supplies power to the rest of behind-the-ear unit245and to transmitter240over one or more power lines (not shown).

Input element housing255houses input element125. Input element125conveys the signal representative of sound to processor130over one or more signal lines. In one implementation, input element housing255and input element125can be interchangeable by a user. With an interchangeable input element125, a user can exchange the input element housing255that houses input element125for a different input element housing255that houses a different input element125. The various interchangeable input elements125can be different devices of the same class or different devices of different classes.

Processor housing260houses processor130and input element120. Processor housing260also includes a power input from supply250, a signal input from input element125, and an output to transmitter240. Divider element265serves as a junction between input element housing255and processor housing260. In one implementation, input element120is a direct input device such as a pressure-sensitive microphone that transduces sound directly to generate a signal representative of sound. Processor130processes the signals generated by input elements120,125for conveyance to the auditory system.

FIG. 3is a flowchart of a process300for processing signals representative of sound for conveyance directly to a subject's auditory system. Process300can be performed by a device such as processor130inFIGS. 1 and 2.

The device performing process300identifies one or more input elements from which it is receiving signals representative of sound at305. An input element can be identified either as a member of a class or uniquely (e.g., as an individual device). The input element identification can be performed automatically, i.e., without human intervention. The input element identification can be triggered by certain events such as, e.g., an exchange between different input elements, a power-on or reset of the audiological system, a user request, or the passage of a predetermined period of time.

An input element can be identified by relying on any of a number of different distinguishing characteristics of the input element. Examples of such distinguishing characteristics include the characteristics of the signal received from the element, the responses of the element to interrogative probing, or the characteristics of an identifying label or tag (such as a globally unique ID number) associated with the input element. In one implementation, different classes of input elements have distinguishing electrical characteristics that identify the classes. The distinguishing electrical characteristics can be inherent to the input elements or input elements can be intentionally designed to possess the distinguishing electrical characteristics. In one implementation, the electrical impedance of different classes of input elements can be designed to have certain values, e.g., by endowing different classes of input elements with distinguishing output impedances. In another implementation, the output impedance of different classes of input elements can be inherently distinguishable.

The device performing process300adjusts processing parameters based on the identity of the input element at310. Processing parameters are quantities, values, or instructions that establish the processing of signals representative of sound. The processing parameters can include, e.g., the gain at which a signal from an input element is amplified, the mixing ratio between signals from two or more input elements, the dynamic range, any time or phase delay applied to a signal, the nature of the passband, and other factors that relate to the conveyance of a signal to the auditory system.

An example of such a factor that relates to the conveyance of a signal to the auditory system is a stimulating strategy. A stimulating strategy is a technique for adapting signals representative of sound for conveyance directly to the auditory system by stimulating nerves in the cochlea. A stimulating strategy can include mapping the sound information to different nerve cells in the cochlea. Such a mapping can include identifying the sound content of certain bandwidths and determining the extent to which certain nerve cells are to be stimulated based on that content. Examples of stimulating strategies are described, e.g., in U.S. Pat. No. 6,289,246 to Faltys et al., the contents of which are incorporated herein by reference.

Another example of a factor that relates to the conveyance of a signal directly to the auditory system is an amplification strategy. When sound information is conveyed to the auditory system by amplifying sound that impinges directly upon the eardrum, an amplification strategy can include identifying the sound content of certain bandwidths and determining the amplification of those bandwidths based on the frequency sensitivity of an individual subject's auditory system.

The device performing process300receives and processes signals representative of sound from one or more input elements in accordance with the adjusted processing parameters at315, and outputs the processed signals to an interface with the auditory system at320.

FIG. 4is a flowchart of a process400for identifying an input element that generates signals representative of sound. Process400can be performed in isolation or process400can be performed as part of a larger process. For example, process400can be performed at305in process300(FIG. 3).

The device performing process400powers on and/or off an input element to be identified at405. The device can, e.g., make or break a power feed to the input element or the device can trigger the input element to turn on and/or turn off internally. Rather than causing the powering on and/or off, the device can also identify when an input element is powered on and/or off.

The device performing process400samples the power-on and/or power-off transients on the input from the input element at405. Sampling at410can be performed continuously or sampling at410can be triggered by the occurrence of a particular event, such as the crossing of a predetermined threshold on the input from the input element. The transients can be sampled directly or after processing.

FIGS. 5-8illustrate example transients for different classes of input elements that can be sampled. In particular,FIG. 5includes traces505,510. Trace505is a power-off transient on the output of an example audio frequency induction loop receiver, and trace510is a power-on transient for the output of the example audio frequency induction loop receiver.

FIG. 6includes traces605,610. Trace605is a power-off transient on the output of an example microphone system, namely the T-MIC system from Advanced Bionics Corporation (Sylmar, Calif.), and trace610is a power-on transient for the T-MIC system.

FIG. 7includes traces705,710. Trace705is a power-off transient on the output of an example low source impedance signal generator, and trace710is a power-on transient for the same low source impedance signal generator. Low source impedance signal generators are devices that generally respond to something other than sound to generate a signal representative of sound. Examples of low source impedance signal generators include MP3 players, CD players, CD/MP3 players, tape players, record players, AM and FM receivers, and television and cable receivers.

FIG. 8includes traces805,810. Trace805is a “power-off” transient when no input element in connected to the input of a device performing process400, and trace810is a “power-on” transient for when no input element in connected. In other words, traces805,810reflect the open input response of the device performing process400.

By appropriate sampling of traces505,510,605,610,705,710,805,810, the device performing process400can acquire distinguishing characteristics of traces505,510,605,610,705,710,805,810.

Returning toFIG. 4, the device performing process400compares the samples of the transients with expected values from different classes of input elements at415. Such a comparison can be made in a number of ways, including comparing the magnitude and/or duration of a transient with predetermined average or expected values. As another example, time/value pairs at predetermined times in the power-on/-off transients can be compared with expected values stored, e.g., in a look-up table.

Based, at least in part, on the result of this comparison, the device performing process400determines the class of the input element at420. The class can be determined by selecting a device class with average or expected characteristics that are most closely matched by the actual characteristics of the transients.

FIG. 9is a flowchart of a process900for adjusting processing parameters based on the identity of one or more input elements that generate signals representative of sound. Process900can be performed in isolation or process900can be performed as part of a larger process. For example, process900can be performed at310in process300(FIG. 3).

The device performing process900can receive a user selection of a program category at905. A program category is a collection of one or more programs for the processing of signals representative of sound. The collection of programs in a program category can share common characteristics that define the category. For example, the programs in a program category can all be directed to improving operation under a certain set of operating conditions. An example of such a program category is the “noise program category” which includes programs for improving operation in noisy environments.

The device performing process900can receive the class identity of one or more input elements at910. The class identity of an input element is an identification of the class, or characteristics of the class, of an input element. For example, a class identity can be an indication that a particular input element is a low source impedance signal generator. As another example, a class identity can be an indication that a particular input element has a certain input impedance and bandwidth.

The device performing process900can, based on the received class identity of the input element and user selection of a program category, select a program within the program category at915. A program is a predetermined association of processing parameters for the processing of signals representative of sound. The parameters in a program can be matched to improve the processing of certain types of signals, such as signals generated by a certain class of input elements. The program can be selected from a library of available programs.

FIG. 10shows an implementation of a program library1000where the relationship between program categories and programs is illustrated. Library1000can be stored in any sort of memory device and can be implemented as any sort of data repository including a database, a data table, a linked list, or other association of records. The memory device storing library1000can be included in an audiological system, e.g., by storing library1000in behind-the-ear unit245or by storing library1000in a self-contained memory device that exchanges data with behind-the-ear unit245(FIG. 2).

Library1000includes three program categories1005,1010,1015. Program categories1005,1010,1015are collections of one or more programs that share common characteristics defining the category. Program category1005includes programs1020,1025,1030. Programs1020,1025,1030are predetermined associations of processing parameters that are coordinated to improve the processing of certain types of signals representative of sound. In particular, program1020is an association of instructions and parameters coordinated to improve the processing of “class 1” input elements, program1025is an association of instructions and parameters coordinated to improve the processing of “class 2” input elements, and program1030is an association of instructions and parameters coordinated to improve the processing of “class 3” input elements. Other programs are available in category1005and in categories1010,1015. Other categories may also be available.

Returning toFIG. 9, the device performing process900can also apply a selected program to a signal processor at920. The application of a program to a signal processor can include an indication to the signal processor to retrieve the selected program from a library such as library1000(FIG. 10) or the input the processing parameters from the selected program directly to the signal processor.

A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. For example, pressure-sensitive input elements can include carbon microphones, piezoelectric microphones, crystal microphones, magnetic microphones, dynamic microphones, capacitor microphones, and/or other elements that are stimulated by sound and generate electrical or other signals. Accordingly, other implementations are within the scope of the following claims.