Patent Grant
7529545
1. Field of the Invention
The present invention relates the field of sound enhancement for mobile phones and other products which produce audio for users, and more particularly to techniques for enhancing sound based upon an individual's hearing profile, based upon environmental factors like noise-induced hearing impairment, and based on personal choice.
2. Description of Related Art
Assessing an individual's hearing profile is important in a variety of contexts. For example, individuals with hearing profiles that are outside of a normal range, must have their profile recorded for the purposes of prescribing hearing aids which fit the individual profile. Typically hearing profile assessments are made by professional audiologists using calibrated and specialized equipment. Therefore, hearing profile assessments have been relatively difficult to obtain and expensive.
A variety of uses for hearing profiles, other than for the purposes of prescribing hearing aids and assistive listening devices, is being developed. For example, hearing profiles of individuals can be utilized for producing customized audio products, such as pre-recorded music that has been modified according to the hearing profile of the listener. One medium for delivering customized audio products is the Internet. See, commonly owned and copending U.S. patent application Ser. No. 09/464,036, filed Dec. 15, 1999, by Pluvinage, et al., entitled “System and Method for Producing and Storing Hearing Profiles and Customized Audio Data Based on Such Hearing Profiles.”
The mobile phone is a unique class of personal audio device, which presents difficulties to persons with hearing profiles that do not fall within the normal ranges. The most common approach to enabling use of mobile phones for hearing impaired persons involves the use of hearing aids. However, digital mobile phones can cause electromagnetic and acoustic interference with digital hearing aids, forcing removal of aids during mobile phone usage, leaving the user with no compensatory signal processing. In one innovative example, mobile phones can be coupled to inductive neck-worn loops as phone accessories, which deliver signals to electromagnetic receivers called “Telecoils” within hearing aids. However the inconvenience and small market penetration of Telecoils in hearing aids makes them a limited solution. Simply increasing amplification in cell phones is another approach with obvious drawbacks.
Previous people have suggested systems that compensate for apparent hearing loss due to background noise masking. Such prior systems are dependent on the use of microphone input signals to determine the amount of background noise. Some of these systems also teach the use of compression for such compensation. Background information including the use of compression in phones is described in Goldberg (U.S. Pat. No. 4,829,565) and Allen & Youtkas (U.S. Pat. No. 5,553,134), although primarily for noise compensation; other patents include: U.S. Pat. No. 5,802,164, U.S. Pat. No. 5,539,806, U.S. Pat. No. 6,061,431, U.S. Pat. No. 5,737,719, U.S. Pat. No. 5,388,185, U.S. Pat. No. 5,896,449 for telephone signal enhancement; U.S. Pat. No. 4,964,304, U.S. Pat. No. 6,071,236, U.S. Pat. No. 3,974,335, and U.S. Pat. No. 5,737,389 for hearing testing over a phone or telecommunications network.
Mobile phones are inherently personal communication devices. Innovations in microelectronics have allowed mobile phones to become extremely portable and wearable, affording access to telecommunications services wherever the service infrastructure is available. Future generation mobile phones may also incorporate entertainment features such as streaming audio and video, playback of stored audio or video, radio reception and presentation, and many other features that deliver audio to the user. It is desirable to enhance the reception of mobile phone system audio by the user, accommodating personal hearing needs, personal choice, or optimization to the noise environment surrounding the user.
The invention disclosed herein is designed to enhance the reception of audio by the listener using a personal communication device, based upon measuring a person's hearing impairment, environmental factors which are modeled as induced hearing loss, and personal choice, and then utilizing signal processing to accommodate for lost functionality of the cochlea suggested by the hearing profile, and to enhance the sound based upon environmental factors, like background noise, and personal choice.
According to the present invention, a mobile phone or other personal communication device includes resources applying measures of an individual's hearing profile, personal choice profile, and induced hearing loss profile, separately or in combination, to build the basis of sound enhancement.
A personal communication device according to the present invention comprises a transmitter/receiver coupled to a communication medium for transmitting and receiving audio signals; control circuitry that controls transmission, reception and processing of call and audio signals; a transducer such as an internal speaker, an external speaker, and a speaker in an attached headset; and an internal microphone, an external microphone, and a microphone in an attached headset. The control circuitry includes logic applying one or more of a hearing profile of the user, a user preference related hearing, and environmental noise factors in processing the audio signals. In various embodiments of the invention, the control circuitry includes instruction memory and an instruction execution processor such as a digital signal processor.
In another embodiment, a personal communication device according to the present invention includes an input device adapted to indicate a volume level for the speaker, and wherein said control circuitry is responsive to volume level to vary multi-band compression parameters applied the audio signals.
In one embodiment, a personal communication device includes control circuitry which applies a composite profile in processing the audio signals, where the composite profile comprises a set of parameters based upon more than one of the hearing profile of the user, the user preference related hearing, and environmental noise factors. In various embodiments, the control circuitry applies more than one of the hearing profile of the user, the user preference related hearing, and environmental noise factors independently in processing the audio signals. Such processing may be done in series by the control circuitry, or in parallel.
In various embodiments, background noise levels are detected using the microphone, an extra sensor which is coupled to the device for sensing environmental noise, and by indirect measures such as the position of a volume control knob, or an indication of a location of use of the device.
In yet another embodiment, the device includes resources for obtaining a hearing profile for a user from a remote source, such as a server coupled to the communication medium. Alternatively, the device may include resources to prompt a user to provide information specifying the hearing profile of the user. In addition, the device may include resources for prompting the user to enter user preference information. In various embodiments, this device includes resources to prompt a user to provide information for use in defining a hearing profile, such as by prompting the user through a hearing test, in which audio stimuli used in the test are produced using transducers, such as the speaker on the device, a speaker attached to the device, or a speaker in a headset coupled to the device.
According to one embodiment of the invention, the personal communication device comprises a mobile phone including an antenna. In this embodiment, the transmitter/receiver comprises a radio coupled to the antenna, and the communication medium is wireless.
According to yet another embodiment of the invention, a telephone communication system is provided which comprises a service provider and a mobile phone.
Other aspects and advantages of the present invention can be seen upon review of the figures, the detailed description and claims which follow.
a-12c are graphs showing various techniques for combining hearing threshold parameters in support of an explanation of processing according to the present invention.
A detailed description of embodiments of the present invention is provided with respect to the Figures, in which
Next generation mobile phones are incorporating features that intersect with the functionality of a small computer, music player, and organizer, and include processing resources for customizing the audio as shown in
The term “personal communication device,” of which the mobile phone is a preferred example, is used throughout this disclosure to indicate a system that has the capability to send and receive a wide variety of audio signals between a remote system and a network infrastructure. The personal communication device could be a very simple system designed to only send and receive voice information, or a complex system that has computational capabilities integrated with or connected to a phone sub-system. The personal communication device could also incorporate phone system attributes combined with audio playback means, where the audio is digitally stored or streamed audio, analog audio playback or other system sound generation. Mobile phones with various combinations of features displays, audio transducers, headsets, and computational tools (e.g. calendar programs, contact list programs, audio playback programs, digital image displays, etc.) in addition to phone call processing are examples of personal communication devices.
Common network protocols for sending and receiving information to and from the mobile phone include AMPS (analog signal), TDMA (time division multiple access) including GSM (general system for mobile), CDMA (code division multiple access), and GPRS (general packet radio service). There are other standards that comprise a sub- or super-set of these general classification; the standards are mentioned here to include signal means between network and mobile phone that span analog, circuit-switched, analog, digital and packet based wireless services. Mobile phones adapted to communication with these protocols are provides with signal processing capability that is increasing in power and flexibility.
Irrespective of the mode of information transmission, the primary function of a personal communication device is audio signal transmission and reception.
Read only program memory 207 stores instructions, parameters and other data for execution by the processing section 203. In addition, a read/write memory 208 stores instructions, parameters and other data for use by the processing section 203. There may be multiple types of read/write memory on the device 200, such as non volatile read/write memory 208 (flash memory or EEPROM for example) and volatile read write memory 209 (DRAM or SRAM for example), as shown in
An input/output controller 210 is coupled to a display 211, to user input devices 212, such as a numerical keypad, a function keypad, and a volume control switch, and to an accessory port (or ports) 213. The accessory port or ports 213 are used for other types of input/output devices, such as binaural and monaural headphones, connections to processing devices such as PDAs, or personal computers, alternative communication channels such as an infrared port or Universal Serial Bus USB port, a portable storage device port, and other things. The controller 210 is coupled to the processing section 203. User input concerning call set up and management, and concerning use of the hearing profile, user preference and environmental noise factors is received via the input devices 212 and optionally via accessories. User interaction is enhanced, and the user is prompted to interact, using the display 211 and optionally other accessories. Input may also be received via the microphone 205 supported by voice recognition programs, and user interaction and prompting may utilize the speaker 206 for various purposes.
In this embodiment of the present invention, the composite or resultant hearing profile 104 of
At any given frequency, the threshold of audibility of a tone can be elevated by a hearing loss at that frequency and by masking of that frequency by competing noise. For normal hearing listeners, the amount of masking at any frequency can be calculated by filtering the amount of noise power out of an auditory filter centered at the frequency of interest. When someone has a hearing loss, there are two factors that can affect audibility at that frequency: the hearing loss and the masking from the noise. Accurately determining the combined result of these two effects is important in order to properly set the parameters of the signal processing algorithm that compensates for reduced audibility. Given the spectral density of a noise, the masked threshold can be calculated for someone with normal hearing by the application of normal auditory filters. The masked threshold of someone with a hearing impairment will depend on the combination of the masking level of the noise and the level of the impairment at each frequency. The threshold from the combined effect (THtot) should be predictable from the threshold due to the impairment (THi) and the masked threshold for normals (THm). In alternative systems, the threshold due to impairment THi could be replaced by, or supplemented with, a threshold parameter THc provided in response to information about a users personal choice, where the subscript “c” represents personal choice for profile.
The solid line in
Three possible ways of combining the hearing loss threshold and the normal masked threshold to predict the combined effect demonstrated in
THtot=max(THi, THm)
and is represented by the dotted line, which has been displaced upwards by 1 dB in order to see the curve in the presence of the other two.
A second possibility is shown by the dotted line in
THtot=10log10[10^(THi/10)+10^(THm/10)].
With this function, the combined eff effect is primarily to take the maximum except in the region where the thresholds are equal where there is an elevating of the combined threshold.
The third and preferred implementation is to combine them in a way that takes into account the compressive properties of the auditory system. This is demonstrated with the dotted line in
THtot=10log10[{10^(p*THi/10)+10^(p*THm/10)−10^(p*THn/10)}^(1/p)]
where THn is the threshold of the normal hearing listener. This function is from Jesteadt et. al (1995). The parameter p represents the amount of compression used during the summation and in the example given has a value of 0.2. This method of calculating the combined effect is consistent with experimental data obtained with hearing impaired subjects.
As mentioned before, THc could also be used in these and similar equations for providing an effective combined profile of a user in a noisy environment.
The effect environmental noise on auditory perception is to reduce the dynamic range available for sounds above the masking level of the environmental noise and to cause abnormal loudness perception of sound heard simultaneously with the noise. Sound ID's Full Frequency Dynamic Compression (FFDC) replicates the compressive function of the healthy cochlea, compressing sound such that the audio signal is no longer distorted in the auditory system and perception is restored to normal.
Compression is functionally an automatic gain control (AGC) within the personal communication device, where the gain reduces as the signal level increases. In order to properly compensate for reduced audibility from the environmental noise, the compression processes the signal in the same way that the cochlea's AGC processes sound in a quiet environment. The input-output function of such a compressor when measured with a quasi-steady-state pure-tone will have a compressive region that has a slope less than or equal to one over a wide dynamic input range (>40 dB), with possible linear regions below and above the compressive region. The gain and compression ratio can vary with frequency and will be monotonic with the noise power in that frequency region. The slope of the compressive region can have values that restore loudness perception to normal in that frequency region, and will have slopes that range from 1 (no compression) to 1/3 (3:1 compression). Because the amount of gain added at any frequency is a function of the power of the signal in that frequency region, the compressor calculates power and applies gain using auditory filter bandwidths that replicate normal critical bands in human hearing. The AGC may be implemented using software executed by a processor in the personal communication device, or by dedicated circuits, or by a combination of these techniques.
The processing system 4 shown in
The processing system 4 could also be the source of profile algorithm control, acoustic stimuli generation, user feedback collection and computation of the hearing profile. The resources of 4 could be used to provide the user or the mobile phone with a PIN code, or directly transfer a profile to the mobile phone through wireless means 7 or direct connection 9. The processing resources of the mobile phone 1 and the processing system 4 could be used in multiple combinations to separate functions such as test protocol control, acoustic stimuli generation, user feedback collection, and profile calculation on either subsystem in any combination. The instructions for such functions can be provided with the phone, downloaded to the phone for execution, or stored and executed in a server which communicates with the phone during the processing, or a provided using a combination of these architectures.
Accessories 10 to the mobile phone may be used in conjunction with the mobile phone and any of the aforementioned subsystems. Accessories 10 may include, for example, monaural or binaural headphones worn by the user. The binaural headphones would allow for gathering of a hearing profile for each ear, which may become more prevalent as mobile phones become stereo audio playback devices. The accessories 10 could communicate with the mobile phone either through direct wire link or wireless link, as shown in
Several strategies for obtaining a measure of the background noise and its concomitant induced hearing impairment are described in the schematic of
Other strategies illustrated with respect to
For some environments, it may be possible to create a common induced profile 15 that could be pre-determined based on knowledge of the environment in question. This could be send to the local processing system 14 and transmitted to the phone through a wireless network 17, an EIN 18 or a direct link 19, or it may be send via the remote processing resources 13 via the cellular transceiver 12. Additionally, a pre-determined induced profile 15 may be transferred to a mobile phone 11 through an external memory system 16.
Accessories 20 to the mobile phone 11 may be used to sense noise, calculate an induced hearing impairment, or even provide computational resources to customize audio. Accessories 20 such as headsets may be used to sense the local noise environment at the user's ear, and send that information to the mobile phone 11 either via a wire link or a wireless link, as shown on the diagram.
The personal choice of an individual may be important in setting customization parameters for delivery of enhanced audio. Similar to the audio delivery section to follow, the creation of personal choice of audio requires generation of example audio sections to allow the user to choose preferences.
Two alternative forced choice (2AFC) test protocols involve presentation of two audio choices, and forcing the user to select the one which sounds better. This choice could be followed by other 2AFC presentations, or upon satisfactory determination of preference setting the preference profile to the last selection of the user. Three alternative forced choice (3AFC) presents the user with three alternatives, two of which are the same and the third which is different. Again, navigation through the forced choices will allow, at the conclusion of the test, determination of the user's preference profile.
Matrix navigation would be presentation of audio that is customized in one or several variables, and depending on user choice, establishing that choice as a vector in personalization. Subsequent presentations of audio customization choices may explore further modification on that vector, and allowing the user to fine tune either one or more variables at each selection of preference.
Staircase test protocols involve presentation of an audio choice, then providing the means for the user to adjust the sound until the user picks a setting that sounds best to the user. The adjustment means on a mobile phone could, for example, be the volume control buttons (physical or logical) or other up/down adjustment means to allow the user to scroll through selections.
As shown in
Customized audio data could be presented to the user through the mobile phone or through accessories 30 such as headsets.
The transfer of a hearing profile can either be automated, or depend on user interaction. In addition, the profile can be either stored locally or transferred to a remote system. These variables combine to make at least six different methods of transferring and storing the hearing profile.
Customization of audio data can be accomplished by using systems remote from the mobile phone, and delivering the customized or personalized audio to the mobile phone for playback. The alternative is to deliver unprocessed audio to the mobile phone, and use the resources of the mobile phone or an accessory to personalize the audio.
The compensation scheme for induced hearing impairment can be active, passive or no monitoring of the environment. Once the environment is monitored, whether actively or passively, compensation can be dynamic or continuously changed, changed in an incremental fashion, or a single setting that is either on or off. If there is no monitoring, then the environmental compensation algorithm can be always on for products that are know to be used in noisy environments.
Customization of audio data can be accomplished by using systems remote from the mobile phone, and delivering the customized or noise compensated audio to the mobile phone for playback. The alternative is to deliver unprocessed audio to the mobile phone, and use the resources of the mobile phone or an accessory to customize the audio to compensate for environmental noise.
Once the hearing profile is acquired and stored for future use, the audio data can be customized or personalized either at the network system resource and transmitted to the phone, or delivered then personalized at a processor on the mobile phone.
Once the induced hearing profile is acquired and stored for use, the audio data can be customized or personalized either at the network system resource and transmitted to the phone, or delivered then customized at a processor on the mobile phone.
A system is provided, suitable for use with wireless communication or portable entertainment devices, that compensates for the apparent hearing loss that is known to manifest itself when listening in a noisy environment. This system is of great interest especially for wireless communication devices because wireless usage patterns naturally include environments that are substantially noisier than the environments typical in traditional PSTN (Public Switched Telephone Network) usage. Such noisy environments include public social environments (restaurants, bars), in-automobile environments, public transportation environments (subways, trains, airports) and other common situations (shopping locations and city/traffic noise).
The system applies a psychoacoustic principle that listeners in noisy environments perceive signals (speech, music . . . the sounds one is trying to hear) as if they had a hearing loss. Hence, the use of techniques well known in the hearing aid industry can be applied to listening in noisy environments as a method of returning intelligibility to normal. Compression algorithms are one such well known technique. Since compression represents a distortion, indiscriminate application of compression will lead to less natural speech. As a result, it becomes important to apply the appropriate amount of compression for a given listening situation.
The process includes:
A number of possibilities of the mapping between volume control knob and coefficient mapping, include the following:
A number of differentiators of this aspect of the present invention include:
Coincidentally, it is recognized that compression solves problems of other difficult listening situations also. In some situations, the speaker may generate a speech signal that has larger than normal dynamic range. In such situation, the listener would want to adjust the volume such that the quietest sounds have a large effective gain while the loud sounds have less gain. This difference in desired gain levels as a function of signal level can be provided through the use of compression. The following situations are likely to lead to large dynamic range speech signals: communication to a speaker phone system, communication with individuals who are actively engaged during communication (i.e. they are on a wireless communication device and doing something), background noise in the speakers environment is changing significantly during the communication.
Similar to a mobile phone handset, portable entertainment systems are often used in high noise environments, for example exercising, outdoor urban activities, etc. Compression of high dynamic range audio entertainment signals, whether received by the audio system or generated from representative digital or analog storage representative of audio, by systems within the portable entertainment system would provide compensation for the noise induced hearing changes experienced by the listener.
Mapping of coefficients could take into account base coefficient values that are representative of a hearing impaired individual's requirements for hearing in quiet. Additional compression, whether in frequency ranges where an individual has impairment, or in frequency bands where no impairment compensation in quiet is required, would be beneficial for the additional hearing changes induced by background noise.
While the present invention is disclosed by reference to the preferred embodiments and examples detailed above, it is to be understood that these examples are intended in an illustrative rather than in a limiting sense. It is contemplated that modifications and combinations will readily occur to those skilled in the art, which modifications and combinations will be within the spirit of the invention and the scope of the appended claims.
This application is a continuation of U.S. patent application Ser. No. 09/957,344 filed 20 Sep. 2001. This application is related to co-pending application number 1121316 filed on Jul. 28, 2005.
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