Patent Publication Number: US-2022233105-A1

Title: In-vehicle hearing test

Description:
BACKGROUND 
     Hearing tests are generally conducted by hearing institutes or laboratories, and are performed using specialized medical devices such as audiometers, special headphones and sealed rooms. The most common type of audiometer generates pure tones, with varying amplitudes as chosen by a human operator, typically a hearing specialist, and delivered to the subject&#39;s ears through the headphones. During testing, the subject indicates that a tone was heard by pressing a feedback button or by a visual signal to the operator. The audiometer enables the operator to produce an audiogram, describing the subject&#39;s hearing acuity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of a system for conducting a hearing test in a passenger compartment of a vehicle. 
         FIG. 2  is a block diagram of the system. 
         FIG. 3  is an illustration of a human machine interface (HMI) of the system. 
         FIG. 4  is a flow chart illustrating a process for conducting the hearing test. 
     
    
    
     DETAILED DESCRIPTION 
     A system includes a computer including a processor and a memory storing instructions executable by the processor to detect a position of a head of an occupant within a passenger compartment of a vehicle. The instructions include instructions to conduct a hearing test based on the position of the head of the occupant. The instructions include instructions to output sound at least at one of a specified frequency or amplitude, the specified frequency or amplitude selected based on results of the hearing test. 
     The instructions may include instructions to select a first amplitude of sound for conducting the hearing test, the first amplitude of sound being determined based on the position of the head. 
     The instructions may include instructions to select a second amplitude of sound for conducting the hearing test, the second amplitude of sound being determined based on the position of the head and different than the first amplitude of sound. 
     The instructions may include instructions to output the first amplitude of sound at a right side of the passenger compartment and the second amplitude of sound at a left side of the passenger compartment. 
     The instructions may include instructions to display, via a human machine interface in the vehicle, the position of the head and a specified head position, and to conduct the hearing test while the position of the head matches the specified head position. 
     The instructions may include instructions to conduct the hearing test while the position of the head matches a specified head position. 
     The instructions may include instructions to detect the position of the head based on data from a camera. 
     The instructions may include instructions to conduct the hearing test in response to determining an ambient noise level in the passenger compartment is below a predetermined threshold. 
     The instructions may include instructions to conduct the hearing test in response to determining an ambient noise level in the passenger compartment has been below a predetermined threshold for a specified amount of time. 
     The instructions may include instructions to estimate the ambient noise level in the passenger compartment based on a speed of the vehicle. 
     The instructions may include instructions to store results of a plurality of hearing tests and to notify the occupant when the results of the plurality of hearing tests indicate deterioration of hearing of the occupant. 
     The instructions may include instructions to limit an amplitude of sound output in the passenger compartment based on the results of the hearing test. 
     The instructions may include instructions to store and associate the results of the hearing test with a profile of the occupant. 
     A method includes detecting a position of a head of an occupant within a passenger compartment of a vehicle. The method includes conducting a hearing test based on the position of the head of the occupant. The method includes outputting sound at least at one of a specified frequency or amplitude, the specified frequency or amplitude selected based on results of the hearing test. 
     The method may include selecting a first amplitude of sound for use while conducting the hearing test, the first amplitude of sound determined based on the position of the head. 
     The method may include selecting a second amplitude of sound for use while conducting the hearing test, the second amplitude of sound determined based on the position of the head and different than the first amplitude of sound. 
     The method may include outputting the first amplitude of sound at a right side of the passenger compartment and the second amplitude of sound at a left side of the compartment. 
     The method may include conducting the hearing test while the position of the head matches a specified head position. 
     The method may include conducting the hearing test after determining an ambient noise level in the passenger compartment has been below a predetermined threshold for a specified amount of time. 
     The method may include estimating the ambient noise level in the passenger compartment based on a speed of the vehicle. 
     The method may include storing results of a plurality of hearing tests and to notify the occupant when the results of the plurality of hearing tests indicate deterioration of hearing of the occupant. 
     The method may include displaying, via a human machine interface in the vehicle, the position of the head and a specified head position, and to conduct the hearing test while the position of the head matches the specified head position. 
     The method may include detecting the position of the head based on data from a camera. 
     The method may include conducting the hearing test in response to determining an ambient noise level in the passenger compartment is below a predetermined threshold. 
     The method may include limiting an amplitude of sound output in the passenger compartment based on the results of the hearing test. 
     A memory may store instructions executable by a processor to perform the method. 
     A system may include a processor and a memory storing instructions executable by the processor to perform the method. 
     With reference to  FIGS. 1 and 2 , wherein like numerals indicate like parts throughout the drawings, a system  10  for controlling sound within a passenger compartment  12  of a vehicle  14  is shown. The system  10  comprises a computer  16  including a processor and a memory storing instructions executable by the processor to detect a position of a head H of an occupant within a passenger compartment  12  of a vehicle  14 . The instructions include instructions to conduct a hearing test based on the position of the head H of the occupant. The instructions include instructions to output sound at least at one of a specified frequency or amplitude, the specified frequency or amplitude selected based on results of the hearing test. 
     In the present description, relative vehicular orientations and directions (by way of example, top, bottom, front, rear, outboard, inboard, inward, outward, lateral, left, right, etc.) are from the perspective of an occupant seated in the vehicle  14  facing forward, e.g., toward a forward instrument panel  18  and/or forward windshield of the vehicle  14 . The forward direction of the vehicle  14  is the direction of movement of the vehicle  14  when the vehicle  14  is engaged in forward drive with wheels of the vehicle  14  straight. 
     Conducting the hearing test based on the position of the head H of the occupant provides more robust and accurate hearing test results, e.g., compared to a hearing test conducted without information indicating the position of the head H of the occupant. For example, a sound output at a right side  20  of the vehicle  14  may be more perceptible to the occupant when seated at the right side  20  than at a left side  22  of the vehicle  14 , and vice versa. Conducting the hearing test based on the position of the head H enables this difference in perception to be accounted for to achieve more accurate hearing test results. 
     The vehicle  14  may be any suitable type of automobile, e.g., a passenger or commercial automobile such as a sedan, a coupe, a truck, a sport utility, a crossover, a van, a minivan, a taxi, a bus, etc. The vehicle  14 , for example, may be autonomous. In other words, the vehicle  14  may be autonomously operated such that the vehicle  14  may be driven without constant attention from a driver, i.e., the vehicle  14  may be self-driving without human input. 
     The vehicle  14  defines the passenger compartment  12 . The passenger compartment  12  houses occupants, if any, of the vehicle  14 . The passenger compartment  12  may extend across the vehicle  14 , i.e., from the right side  20  to the left side  22  of the vehicle  14 . The passenger compartment  12  includes a front end  24  and a rear end  26  with the front end  24  being in front of the rear end  26  during forward movement of the vehicle  14 . 
     The vehicle  14  defines a longitudinal axis A 1  extending between the front and the rear of the vehicle  14 . The vehicle  14  defines a cross-vehicle axis A 2  extending between the right side  20  and the left side  22  of the vehicle  14 . The longitudinal axis A 1  and the cross-vehicle axis A 2  are perpendicular relative to each other. The longitudinal axis A 1  and the cross-vehicle axis A 2  are generally shown extending through a center of the vehicle  14 , however, the longitudinal axis A 1  and the cross-vehicle axis A 2  do not necessarily define lateral or cross-vehicle centers. 
     The vehicle  14  may include one or more speakers  28 RF,  28 RR,  28 LF,  28 LR that can convert an electrical signal to sound, i.e., each speaker  28 RF,  28 RR,  28 LF,  28 LR may include a transducer that converts the electric signal to vibrations to generate sound at a desired frequency. Each speaker  28 RF,  28 RR,  28 LF,  28 LR can receive the electrical signal from an audio amplifier. The audio amplifier, as is known, can amplify an electric signal provided to drive one or more of the speakers  28 RF,  28 RR,  28 LF,  28 LR. The amplifier can be used to control amplitude of a signal, e.g., amplitude of a sound (e.g., in decibels) of a sound to be output by the speakers  28 RF,  28 RR,  28 LF,  28 LR. One or more of the speakers  28 RF,  28 RR,  28 LF,  28 LR may be actuated to generate sound, e.g., in response to a command from the computer  16 . The speakers  28 RF,  28 RR,  28 LF,  28 LR may be supported by the vehicle  14  at various positions within the passenger compartment  12 . For example, a right-front speaker  28 RF supported at the right side  20  and the front end  24 , a right-rear speaker  28 RR supported the right side  20  and the rear end  26 , a left-front speaker  28 LF supported at the left side  22  and the front end  24 , and a left-rear speaker  28 LR supported at the left side  22  and the rear end  26 . 
     The vehicle  14  includes sensors  30  that can obtain one or more measurements of one or more physical phenomena. Often, but not necessarily, a sensor includes a digital-to-analog converter to converted sensed analog data to a digital signal that can be provided to a digital computer, e.g., via a network. Sensors  30  can include a variety of devices, and can be disposed to sense an environment, provide data about a machine, etc., in a variety of ways. For example, sensors  30  could include cameras, short range radar, long range radar, LIDAR, and/or ultrasonic transducers, weight sensors, accelerometers, motion detectors, etc., i.e., sensors  30  to provide a variety of data. To provide just a few non-limiting examples, sensor data could include data for determining a position of a component, a location of an object, a speed of an object, a type of an object, a slope of a roadway, a temperature, an presence or amount of moisture, a fuel level, a data rate, etc. The sensors  30  may provide sensor data to the computer  16 . 
     One or more of the sensors  30  may be vehicle speed sensors that output a vehicle speed, i.e., a rate of movement of the vehicle  14 , typically in the forward direction, with respect to a ground surface such as a road. For example, one or more wheel speed sensors can be provided as is known to detect a rate of rotation of vehicle wheels, from which a speed of the vehicle  14  can be determined. Alternatively or additionally, a vehicle speed sensor can detect a rate of rotation of a crankshaft, from which the vehicle  14  speed can be determined. 
     One or more of the sensors  30  may be occupant sensors that detect the position of the head H of the occupant relative to the passenger compartment  12 . For example, one or more image sensors may be supported within the passenger compartment  12 , e.g., by the instrument panel  18  or the like, and be orientated toward a top portion of one of the seats. An image sensor could include one or more cameras, CCD image sensors, CMOS image sensors, etc. As another example, proximity sensors, such as a capacitive proximity sensor, a photoelectric sensor, an infrared proximity sensor, etc., may be supported by a pillar, roof, etc., and orientated toward a top portion of one of the seats to detect a distance to the head H. Other sensors  30  may be used to detect the position of the head H. 
     The system  10  can include one or more human-machine-interfaces (HMIs)  32 A,  32 B. The HMIs  32 A,  32 B may provide information to, and/or receive information from, the occupant. The HMIs  32 A,  32 B may include, e.g., one or more of a display, a touchscreen display, a microphone, a speaker, etc. The HMI  32 A may be supported by the vehicle  14 , e.g., fixed to the instrument panel  18 . The HMI  32 B may be separate from vehicle  14 , e.g., a smart phone, tablet computer, etc., which the occupant may bring into the passenger compartment  12 . The HMI  32 A,  32 B may provide information to, and/or receive information from, the computer  16 . 
     The computer  16  is a microprocessor-based controller implemented via circuits, chips, or other electronic components. The computer  16  includes a processor and a memory such as are known. The memory includes one or more forms of computer readable media, and stores instructions executable by the computer  16  for performing various operations, including as disclosed herein. The computer  16  may be programmed to execute operations disclosed herein. Specifically, the memory stores instructions executable by the processor to execute the operations disclosed herein and electronically stores data and/or databases. For example, the computer  16  may include one or more dedicated electronic circuit including an ASIC (Application Specific Integrated Circuit) that is manufactured for a particular operation. In another example, the computer  16  may include an FPGA (Field Programmable Gate Array) which is an integrated circuit manufactured to be configurable by a customer. As an example, a hardware description language such as VHDL (Very High Speed Integrated Circuit Hardware Description Language) is used in electronic design automation to describe digital and mixed-signal systems such as FPGA and ASIC. For example, an ASIC is manufactured based on VHDL programming provided pre-manufacturing, and logical components inside an FPGA may be configured based on VHDL programming, e.g. stored in a memory electrically connected to the FPGA circuit. In some examples, a combination of processor(s), ASIC(s), and/or FPGA circuits may be included inside a chip packaging. The computer  16  may be a set of computers communicating with one another. 
     The computer  16  is generally arranged for communications on the communication network  34  that can include a bus in the vehicle  14  such as a controller area network (CAN) or the like, and/or other wired and/or wireless mechanisms. Via the communication network  34 , the computer  16  may transmit messages to various devices in the vehicle  14 , and/or receive messages (e.g., CAN messages) from the various devices, e.g., the HMI  32 A supported on the instrument panel  18 , the speakers  28 RF,  28 RR,  28 LF,  28 LR, the various sensors  30 , etc. Alternatively or additionally, in cases where the computer  16  comprises a plurality of devices, the communication network  34  may be used for communications between devices represented as the computer  16  in this disclosure. 
     The computer  16  can communicate, typically via a wireless connection, with one or more remote computers that are physically separate, and typically geographically remote, from the vehicle  14 , such as communicating with the HMI  32 B that is a tablet computer, etc. The computer  16  may provide data to, and receive data from, the remote computers via a network. The network represents one or more mechanisms by which the computer  16  of the vehicle  14  may communicate with the remote computers. Accordingly, the network can be one or more of various wired or wireless communication mechanisms, including any desired combination of wired (e.g., cable and fiber) and/or wireless (e.g., cellular, wireless, satellite, microwave, and radio frequency) communication mechanisms and any desired network topology (or topologies when multiple communication mechanisms are utilized). Exemplary networks include wireless communication networks (e.g., using Bluetooth®, Bluetooth® Low Energy (BLE), IEEE 802.11, Dedicated Short Range Communications (DSRC), etc.), local area networks (LAN) and/or wide area networks (WAN), including the Internet, providing data communication services. The network can be a vehicle-to-everything network (V2X), where “X” signifies an entity with which the computer  16  of the vehicle  14  can communicate with, e.g., a vehicle (V2V), infrastructure (V2I), a pedestrian (V2P), etc. The computer  16  can communicate with one or more devices over the V2X network, e.g., with another vehicle, with a device mounted to infrastructure, to a user device separate from the vehicle  14  (such as the HMI  32 B), etc. One example of a V2X network is a cellular-V2X (C-V2X) network. The C-V2X network is a band of frequencies dedicated to V2X communications, e.g., between vehicles, portable devices, etc. For example, the C-V2X network can include frequencies between 5.90 and 5.99 gigahertz (GHz) (e.g., 5.85-5.925 GHz). 
     The computer  16  is programmed to, i.e., the memory stores instructions executable by the processor to, detect the position of the head H of the occupant within the passenger compartment  12  of the vehicle  14 . The detected position of the head H is relative to the passenger compartment  12 , e.g., relative to the right side  20 , the left side  22 , the front end  24 , the rear end  26 , one or more or the speakers  28 RF,  28 RR,  28 LF,  28 LR, etc. The detected position of the head H may be identified as coordinates along the longitudinal axis A 1  and/or cross-vehicle axis A 2 . The computer  16  may detect the position of the head H with data from the sensors  30 , e.g., from a camera and/or a proximity sensor. For example, pixels values of image data from a camera fixed relative to the passenger compartment  12  may be analyzed to identify the head H of the occupant in such image data, e.g., using any suitable image analysis technique, e.g., techniques are known for determining an orientation or pose of a part of a human body, e.g., as described in  Face - from - Depth for Head Pose Estimation on Depth Images  dated 12 Dec. 2017 and other papers available at https://paperswitcode.com/task/head-pose-estimation/codeless (accessed on 20 Jan. 2021). The computer  16  may determine the position of the head H relative to the passenger compartment  12  based on a position of the head H identified in the image data. For example, the computer  16  may store a look-up table, formula, or the like that correlates positions of the head H identified in the image data (e.g., as pixel coordinate data) with actual positions within the passenger compartment  12  (e.g., as coordinates along the longitudinal axis A 1  and/or the longitudinal axis A 2 ). As another example, distance data from a proximity sensor fixed to one of the pillars may indicate a distance of the head H from the right side  20  or the left side  22 . 
     The computer  16  is programmed to conduct a hearing test. The hearing test provides results that indicate an ability (or deficiency) of ears of the occupant to perceive various amplitudes (i.e., volumes) and frequencies (i.e., pitches) of sound. The hearing test may be a “pure tone” type test. For example, the computer  16  may command one or more of the speakers  28 RF,  28 RR,  28 LF,  28 LR to output a series of sounds at progressively increasing amplitudes and at various frequencies, e.g., between 125 Hz-8 kHz. The sound may be output at the right side  20  and not the left side  22 , and vice versa. While the sound is being output the computer  16  may command the HMI  32 A,  32 B to output an indication requesting feedback from the occupant, e.g., the computer  16  may command a screen  36  of the HMI  32 A,  32 B to display text specifying that input is needed when the occupant perceives the sound. The occupant may provide an input to the HMI  32 A,  32 B when the sound is perceived, e.g., via a touch screen, steering wheel buttons, etc. The input from the occupant may specify whether the sound is perceived from the right side  20  or the left side  22 . The computer  16  may store the results of the hearing test, e.g., which amplitudes and frequencies of sound the occupant indicated perceiving from the right side  20  and/or the left side  22 . The stored results may include a time and date at which the test results were generated. The computer  16  may associate the results of the hearing test with an occupant profile that includes information about the occupant. The computer  16  may select which occupant profile to associate the results of the hearing test with from among a plurality occupant profiles by receiving information from the HMI  32 A,  32 B (e.g., indicating the occupant has selected a specific occupant profile), by establishing a connection with a certain key fob, smart phone, or other electronic device, or with other conventional structure and methods. 
     The computer  16  is programmed to conduct the hearing test based on the position of the head H of the occupant, e.g., as detected by the sensor  30 . The computer  16  may conduct the hearing test, for example, in response to receiving data from the HMI  32 A,  32 B indicating the occupant has requested the hearing test, upon initial setup of a new occupant profile, and/or after a predetermined amount of time (e.g., 6 months) has lapsed since previously conducting the hearing test. 
     The computer  16  may conduct the hearing test based on the position of the head H using specified amplitudes for the hearing testing that are determined based on the position of the head H. Conducting the hearing test based on the position of the head H enables compensation for a distance between the head H of the occupant and the various speakers  28 RF,  28 RR,  28 LF,  28 LR, e.g., when testing with sound generated from a specific one of the sides and such that the amplitude generated by the speakers  28 RF,  28 RR, at the right side  20  or the speakers  28 LF,  28 LR at the left side  22  can perceived at the position of the head H at a certain amplitude. Conducting the hearing test based on the position of the head H enables the sound generated by the speakers  28 RF,  28 RR,  28 LF,  28 LR to be balanced at the head H position, e.g., such that the sound perceived at the position of the head H is similar from each of the speakers  28 RF,  28 RR,  28 LF,  28 LR. 
     As one example, when the hearing test is being conducted at the right side  20 , the computer  16  may select an amplitude of sound for generation by the speakers  28 RF,  28 RR at the right side  20  based on a distance between the right side  20  and the position of the head H of the occupant. Similarly, when the hearing test is being conducted at the left side  22 , the computer  16  may select an amplitude of sound for generation by the speakers  28 LF,  28 LR at the left side  22  based on a distance between the left side  22  and the position of the head H of the occupant, e.g., according to a formula or table as described below. The amplitude of the sound generated for the hearing test by the speakers  28 RF,  28 RR at the right side  20  may be relatively lower when the head H is relatively closer to such speakers  28 RF,  28 RR and relatively higher when the head H is relatively farther from such speakers  28 RF,  28 RR. Similarly, the amplitude of the sound generated for the hearing test by the speakers  28 LF,  28 LR at the left side  22  may be relatively lower when the head H is relatively closer to such speakers  28 LF,  28 LR and relatively higher when the head H is relatively farther from such speakers  28 LF,  28 LR. 
     As another example, when conducting the hearing test with the speakers  28 RF,  28 RR,  28 LF,  28 LR at the right side  20  and the left side  22 , the computer  16  may select various amplitudes for the speakers  28 RF,  28 RR,  28 LF,  28 LR such that the amplitude of sound from the speakers  28 RF,  28 RR,  28 LF,  28 LR is perceived at the position of the head H to be generally the same. For example, the computer  16  may select, based on the position of the head H, a first amplitude and a second amplitude of sound that are different from each other. During the hearing test, the computer  16  may output sound at the first amplitude with the speakers  28 RF,  28 RR on the right side  20  of the passenger compartment  12  and sound at the second amplitude with speakers  28 LF,  28 LR at the left side  22  of the compartment. As the position of the head H moves away from the right side  20  and toward the left side  22  the first amplitude is relatively increased, and the second amplitude is relatively decreased. Conversely, as the position of the head H moves towards the right side  20  and away from the left side  22 , the first amplitude is relatively decreased, and the second amplitude is relatively increased. 
     The computer  16  may select amplitudes for the hearing test with a look up table, formula, or the like that associates various distances from the right side  20  and/or the left side  22  with various amplitudes, and/or associates various positions along the cross-vehicle axis A 2  with various first amplitudes and second amplitudes. The look-up table, the formula, etc., provide selected amplitudes that increase along with an increase in distance from the respective side. The look-up table, the formula, etc., provide selected first and second amplitudes that balance the sound at the position of the head H. The look up table, formula, or the like may be populated, derived, or otherwise determined based on empirical testing, computer modeling, and/or other analysis of sound within the passenger compartment  12 . For example, sound may be output at a specified amplitude by one of the speakers  28 RF,  28 RR,  28 LF,  28 LR and decibel levels of such sound at various positions within the passenger compartment  12  may then be measured. compartment  12 . As another example, decibel levels at various locations may be measured while an amplitude of the sound output by one of the speakers  28 RF,  28 RR,  28 LF,  28 LR is varied. The measured decibel levels indicate perceptible amplitudes of the sound at the various positions when output at the various amplitudes. Differences between the known amplitude of the sound as output and the decibel levels measured at the various positions indicates a relationship of the respective distances between the speakers  28 RF,  28 RR,  28 LF,  28 LR and the various measurement positions, taking into account acoustical properties of the passenger compartment  12 . The amplitudes in a look up table, or determined from a formula, or the like can account for the distance of a speaker  28 RF,  28 RR,  28 LF,  28 LR taking into account acoustical properties of a cabin in which the speaker  28 RF,  28 RR,  28 LF,  28 LR is located. For example, the field of audiology can provide amplitudes appropriate for evaluating hearing, and such amplitudes may be adjusted, i.e., increased or decreased, for inclusion in a lookup table based on the differences between the known amplitude of the sound as output and the decibel levels measured at the various positions such that an occupant with a head H at one of the various positions perceives sound output by the speakers as the amplitudes provided by the audiologist. Alternatively or additionally, a formula may be derived using the amplitudes provided by the audiologist and based on the differences between the known amplitude of the sound as output and the decibel levels measured at the various positions such that the occupant with the head H at one of the various positions perceives sound output by the speakers as the known amplitudes. 
     The computer  16  may conduct the hearing test based on the position of the head H by conducting the hearing test while the position of the head H matches a specified head position. The specified position may be prestored in memory, e.g., generally centered relative to the seat supporting the occupant and along the cross-vehicle axis A 2 . The specified position may be the detected position of the head H at initiation of the hearing test, e.g., as detected by the occupant sensor. The computer  16  may command the speakers  28 RF,  28 RR,  28 LF,  28 LR to generate sound for the hearing test while the head H is at the specified position, and may control the speakers  28 RF,  28 RR,  28 LF,  28 LR such that sound for the hearing test is not generated while the head H is spaced from the specified position. In other words, the computer  16  may only initiate the hearing test when the head H is at the specified position, and/or may pause the hear test when the head H is not at the specified position and then resume when the head H is at the specified position. 
     To assist the occupant in placing their head H at the specified position, the computer  16  may display, via the HMI  32 A,  32 B in the vehicle  14 , an indication of the detected position of the head H and the specified position of the head H. For example, and as shown in  FIG. 3 , the computer  16  may command the screen  36  of the HMI  32 A,  32 B to display the head H of the occupant as captured by a camera and an outline  38  indicating the specified head position. The occupant may then move their head H to be within the outline  38 . 
     The computer  16  may be programmed to determine an ambient noise level in the passenger compartment  12 , i.e., a level of noise (e.g., typically specified as a combination of frequency and amplitude, e.g., in Hertz and decibels) in the passenger compartment  12  other than from sound generated for the hearing test. The computer  16  may determine the ambient noise level based on data from one or more of the sensors  30 , e.g., data from a microphone or pressure transducer may indicate the ambient noise level while the speakers  28 RF,  28 RR,  28 LF,  28 LR are not generating sound for the hearing test. The computer  16  may determine the ambient noise level with an estimation based on a speed of the vehicle  14 , e.g., as detected by the sensors  30 . For example, the computer  16  may store a look up table, formula, or the like that associates various vehicle speeds with ambient noise levels. The look up table, formula, etc., may be determined based on empirical testing, e.g., measuring and storing a level of detected ambient noise in the passenger compartment  12  at various speeds of the vehicle  14 . 
     The computer  16  may be programmed to determine whether the ambient noise level is below a first predetermined threshold. The first predetermined threshold is set such that ambient noise at a level below the first predetermined threshold is unlikely to interfere with the hearing test. For example, ambient sound above the first predetermined threshold may interfere with sound generated by the speakers  28 RF,  28 RR,  28 LF,  28 LR for the hearing test and result in relatively less accurate results. The computer  16  may determine whether the ambient noise level is below the first predetermined threshold by comparing such values with each other. For example, the computer  16  may compare data from the microphone indicating the level of ambient noise with the first predetermined threshold. The computer  16  may conduct the hearing test after determining the ambient noise level in the passenger compartment  12  is below the first predetermined threshold. 
     The computer  16  may be programmed to determine whether the ambient noise level is below a second predetermined threshold for a specified amount of time. The second predetermined threshold and specified time are set such that exposure the ambient sound above the second predetermined for the specified amount of time is likely to degrade the occupant&#39;s ability to perceive sounds. For example, results for a hearing test conducted on the occupant directly after being exposed to ambient noise at the second predetermined threshold for the specified amount of time may be inaccurate and indicate degraded hearing compared to results of a hearing test conducted when such occupant has not been exposed to ambient noise at the second predetermined threshold for the specified amount of time. 
     The first threshold, the second threshold, and the specified amount of time may be empirically determined. For example, results of various hearing tests conducted with various levels of ambient noise and/or with occupants exposed to various levels of ambient noise for various lengths of time before taking the hearing tests may be compared to results of hearing test conducted without exposure to such ambient noise. The comparison may indicate what level of ambient noise, and/or, what length of time of exposure to ambient noise, interferes with obtaining accurate results with the hearing test. 
     The computer  16  may be programmed to actuate the speakers  28 RF,  28 RR,  28 LF,  28 LR, the HMI  32 A,  32 B, etc., to output sounds at specified frequencies and/or amplitudes based on the results of the hearing test. For example, the results of the hearing test may indicate that the occupant is relatively more likely to perceive sound at a first frequency and relatively less likely to perceive sound at a second frequency. The computer  16  may actuate the speakers  28 RF,  28 RR,  28 LF,  28 LR, the HMI  32 A,  32 B, etc., to output sounds at the first frequency identified by the test to be more likely perceptible by the occupant, e.g., to notify the occupant that a fuel reserve is low, that a check engine light has illuminated, that air pressure in a tire of the vehicle  14  may be low, etc. 
     The computer  16  may be programmed to limit an amplitude of sound output in the passenger compartment  12  based on the results of the hearing test. The computer  16  may limit a maximum amplitude of sound output by the speakers  28 RF,  28 RR,  28 LF,  28 LR, the HMI  32 A,  32 B, etc., by commanding only the speakers  28 RF,  28 RR,  28 LF,  28 LR, the HMI  32 A,  32 B, etc., to generate sounds below the maximum amplitude. For example, results of one or more of the hearing test may indicate hearing loss of the occupant, e.g., the results may indicate that the occupant does not perceive certain frequencies of sounds at amplitudes that are typically perceivable by a human and/or that the perceptibility of certain frequencies of sound by the occupant has degraded across multiple hearing tests. When the results indicate hearing loss, limiting the amplitude of the sound to below the maximum amplitude may reduce a rate of such hearing loss of the occupant. The maximum amplitude may be determined by standard audiology techniques, e.g., indicating what levels of amplitude of sounds are either unlikely or likely to contribute to hearing loss. The computer  16  may limit amplitude at specific frequencies. For example, the results of the hearing test may indicate that the occupant only has difficulty perceiving certain frequencies of sounds. In such case, the computer  16  may limit the amplitude of sound generated at those certain frequencies. 
     The computer  16  may be programed to notify the occupant when results of a plurality of hearing tests, e.g., stored in memory and associated with the occupant&#39;s user profile, indicate deterioration of hearing of the occupant. The computer  16  may determine whether the results of the plurality of hearing test indicate hearing deterioration by comparing results of respective hearing tests with each other. For example, the computer  16  may determine that hearing of the occupant has deteriorated when the likelihood of perception of sounds at various frequencies and amplitudes is shown by the results to have decreased over time. The computer  16  may indicate such deterioration of hearing to the occupant, e.g., by commanding the screen  36  of the HMI  32 A,  32 B to display such information, by sending a message to an email address associated with the user profile, etc. 
       FIG. 4  shows a process flow diagram illustrating an exemplary process  400  for operating the system  10 . The process  400  begins in a block  405  in which the computer  16  collects data, e.g., received from the sensors  30 , the HMI  32 A,  32 B, etc. The computer  16  may receive data substantially continuously or at intervals, e.g., periodically such as every  100  milliseconds. The computer  16  may store the data, e.g., in memory. 
     At a block  410  the computer  16  receives a request to initiate a hearing test, e.g., from the HMI  32 A,  32 B, via the communication network. The HMI  32 A,  32 B may send the request to the computer  16  in response to receiving input, e.g., by the occupant. Alternatively or additionally, the computer  16  may include and could execute programming to determine to initiate a hearing test, e.g., based on an amount of time since the previous hearing test, etc. 
     Next at a block  415  the computer  16  determines whether an ambient noise level in the passenger compartment  12  is below a first predetermined threshold, e.g., based on data from one or more sensors  30  such as a microphone. The first predetermined threshold is set such that ambient noise at a level below the first predetermined threshold is unlikely to interfere with the hearing test, e.g., as described herein. In response to determining the ambient noise in the passenger compartment  12  is not below the first predetermined threshold the computer  16  may command the HMI  32 A,  32 B to indicate that the ambient noise level is too high for conducting a hearing test and return to the block  405 . In response to determining the ambient noise in the passenger compartment  12  is below the first predetermined threshold, the computer  16  may move to a block  420 . 
     At the block  420  the computer  16  determines whether the ambient noise level in the passenger compartment  12  has been below a second predetermined threshold for a specified amount of time, e.g., with data from the microphone, with an estimate the based on a speed of the vehicle  14 , etc. The second predetermined threshold and specified amount of time may be set such that exposure to the ambient sound above the second predetermined for the specified amount of time is likely to degrade the occupant&#39;s ability to perceive sound, e.g., as described herein. In response to determining the ambient noise level in the passenger compartment  12  has not been below the second predetermined threshold for the specified amount of time, the computer  16  may command the HMI  32 A,  32 B to indicate to the user that the ambient noise level has been too high for too long to conduct the test and the computer  16  may return to the block  405 . In response to determining the ambient noise level in the passenger compartment  12  has been below the second predetermined threshold for the specified amount of time, the computer  16  may move to a block  425 . 
     At the block  425  the computer  16  detects a position, e.g., an initial position, of the head H of an occupant within the passenger compartment  12  of the vehicle  14 , e.g., based on data from one or more of the sensors  30 , such as data from an occupant sensor, and as described herein. The computer  16  may, for example, detect a distance from the head H to the right side  20  and/or the left side  22 , a position of the head H along the cross-vehicle axis A 2  and/or the longitudinal axis A 1 , etc. The computer may store the detected position of the head in memory. 
     Next at a block  430  the computer  16  conducts a hearing test based on the position of the head H of the occupant detected at the block  425 . For example, the computer  16  may select various amplitudes for the speakers  28 RF,  28 RR,  28 LF,  28 LR such that the amplitude of sound from the speakers  28 RF,  28 RR,  28 LF,  28 LR is perceived at the position of the head H to be generally the same. As another example, the computer  16  may select an amplitude of sound for generation by the speakers  28 RF,  28 RR at the right side  20  based on a distance between the right side  20  and the position of the head H of the occupant. The computer  16  may select the amplitudes with a look up table, formula, or the like, e.g., as described herein. After selecting the amplitudes, the computer  16  command one or more of the speakers  28 RF,  28 RR,  28 LF,  28 LR to output a series of sounds at the selected amplitudes (e.g., the computer  16  may conduct a “pure type” type test with the selected amplitudes). The computer  16  may command the screen  36  of the HMI  32 A,  32 B to display text specifying that input is needed when the occupant perceives the sound at the selected amplitudes while such sounds are output. The computer  16  may receive, e.g., from the HMI  32 A,  32 B, indicating that the sounds have been perceived by the occupant. 
     The computer may continue to conduct the hearing test only while the position of the head H matches a specified head position. The specified head position may be the initial position of the head detected at the block  425 . For example, the computer  16  may continue to detect the head position while conducting the hearing test, e.g., substantially continuously or at intervals such that the computer  16  receives a generally current position of the head, and may compare the current position with the specified head position. Upon determining that the current head position and the specified head position match, the computer  16  may continue to generate sounds for the hearing test. Upon determined the current head position and the specified head position do not match, the computer  16  may pause generation of sound for the hearing test, resuming when the current position matches the specified position. To assist the occupant in maintaining their head H at the specified head position while conducting the hearing test, the computer may display the position of the head H and the specified head position to the occupant, e.g., as an image of the head H and an outline  38  indicating the specified head position on the screen  36  of the HMI  32 A,  32 B, as illustrated in  FIG. 3 . The computer may associate the results of the hearing test with a profile of the occupant and save the results and association in memory. 
     At a block  435 , the computer may output sound at least at one of a specified frequency or amplitude, the specified frequency and/or amplitude selected based on results of the hearing test conducted at the block  430 , e.g., by commanding one or more of the speakers  28 RF,  28 RR,  28 LF,  28 LR to generates sound at such frequency and/or amplitude. For example, the computer  16  may command the speakers  28 RF,  28 RR,  28 LF,  28 LR to generate sound at a certain frequency to alert the occupant and/or may limit a maximum amplitude of the sound generated in the passenger compartment  12 , e.g., as described herein. 
     At a block  440 , the computer may to notify the occupant when the results of the hearing test conducted at the block  430  and results of one or more previously conducted and stored hearing tests indicate deterioration of hearing of the occupant, e.g., as described herein. The computer may, for example, notify the occupant via the HMI  32 A,  32 B. 
     In the drawings, the same reference numbers indicate the same elements. Further, some or all of these elements could be changed. With regard to the media, processes, systems, methods, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain embodiments, and should in no way be construed so as to limit the claimed invention. 
     Computer executable instructions may be compiled or interpreted from computer programs created using a variety of programming languages and/or technologies, including, without limitation, and either alone or in combination, Java™, C, C++, Visual Basic, Java Script, Perl, HTML, etc. In general, a processor (e.g., a microprocessor) receives instructions, e.g., from a memory, a computer readable medium, etc., and executes these instructions, thereby performing one or more processes, including one or more of the processes described herein. Such instructions and other data may be stored and transmitted using a variety of computer readable media. A file in a networked device is generally a collection of data stored on a computer readable medium, such as a storage medium, a random access memory, etc. 
     A computer readable medium includes any medium that participates in providing data (e.g., instructions), which may be read by a computer. Such a medium may take many forms, including, but not limited to, non volatile media, volatile media, etc. Non volatile media include, for example, optical or magnetic disks and other persistent memory. Volatile media include dynamic random access memory (DRAM), which typically constitutes a main memory. Common forms of computer readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD ROM, DVD, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, an EPROM, a FLASH EEPROM, any other memory chip or cartridge, or any other medium from which a computer can read. 
     Use of “in response to,” “based on,” and “upon determining” herein indicates a causal relationship, not merely a temporal relationship. 
     The disclosure has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described.