System and Method for Spectral Personalization of Sound

• US 20130136282A1
• Filed: 06/05/2012
• Published: 05/30/2013
• Est. Priority Date: 11/30/2011
• Status: Abandoned Application

• Current Assignee: David Mcclain
• Original Assignee: David Mcclain
• Inventors: McClain, David
• Application Number:
  US13/489,281
• Publication Number:
  US 20130136282A1
• Time in Patent Office: Days
• US Class Current: 381/316
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level
• CPC Class Codes: H03G 9/005 of digital or coded signals
• CPC Class Codes: H03G 9/025 frequency-dependent volume compression or expansion, e.g. multiple-band systems H03G9/10, H03G9/18 take precedence

Abstract

The present invention features systems for enhancing audio signals to correct across a spectrum of frequencies according to a model of the spectral characteristics of hearing loss. The methods of the present invention estimate hearing loss using a linear function of the critical band center frequency. The systems of the present invention compute a user-determined degree of correction to sounds at varying frequencies, allowing a listener to hear sounds, across varying frequencies, as the listener wishes to hear them without needing to raise the volume of the sounds to potentially damaging levels. Systems may be incorporated into apparatuses including but not limited to personal communications devices, virtual audio ports/channels and media players.

Claims

1. An apparatus 700, effective for selecting a plurality of threshold elevations for a given user, without requiring individual measurement of each threshold elevation, where the apparatus calculates a plurality of spectrally varying threshold elevations across a plurality of channels and where the threshold elevations are computed from a single parameter set by a user-adjustable input device 703, each of the threshold elevations being represented as X₀, in dBHL at a given frequency F, and where each of the threshold elevations can be used to determine corresponding correction gains, the apparatus comprising:

a. the input device 703, which allows a user to set the single parameter for a personalized sound adjustment model 706; and

b. a microprocessor 701, in electronic communication with the input device 703, the microprocessor 701 configured to execute an application comprising the personalized sound adjustment model 706, where the personalized sound adjustment model 706 generates a spectrum of threshold elevations corresponding to a plurality of frequency components, based on the parameter set to the input device 703;

wherein the user sets the single parameter via the input device 703, and thereafter, the input device 703 transmits information about the single parameter to the microprocessor 701, whereupon the microprocessor 701 applies the parameter to the personalized sound adjustment model 706, whereupon the personalized sound adjustment model 706, using the single parameter, generates a spectrum of threshold elevations, per frequency component, and where said threshold elevations are effective for identifying threshold levels of hearing for users with impaired hearing or for users with normal hearing who wish to optimize their perceived hearing.

3. The apparatus of claim 1-2, wherein the apparatus further comprises:

a. an audio device 702, 802, configured to identify an audio signal x(t) where the audio signal is a broadband audio signal of interest, the audio device operatively connected to the microprocessor 702, 802;

b. a frequency analysis module 704, 804 configured to extract a plurality of frequency components from the audio signal;

c. a kHz frequency to critical band center frequency converter component 705, 805;

d. a psychoacoustic model 707, 807 which, using the threshold elevation for each frequency component, computes corresponding gains for each frequency component of the audio signal;

e. a gain block component 708, 808 which applies gains to each frequency component of the audio signal; and

a

f. a frequency synthesis module 709, 809 which reconstitutes the audio signal from the frequency components, with the corrected gains;

wherein the audio device 702, 802 extracts the audio signal x(t), which is then input to the microprocessor 701, 801 through an analog to digital converter,

whereupon, the microprocessor 701, 801 uses the frequency analysis module 704, 804, to decompose the audio signal into a plurality of frequency components,

whereupon, for each component, the equivalent critical band center frequency F is computed 705, 805,

and whereupon, the personalized sound adjustment model 706, 806 generates, for each frequency component, a threshold elevation value for X₀,

whereupon the microprocessor 701, 801 calculates, for each frequency component, a correction gain Δ

X for the audio signal, using the psychoacoustic model 707, 807 and the corresponding threshold elevation,

whereupon the microprocessor 701, 801 applies the corrective gain to each frequency component of the audio signal,

whereupon the microprocessor 701, 801 reconstitutes the corrected audio signal by summing the frequency components, producing x_out(t) 709, 809.

5. The apparatus of claims 3-4, wherein the Frequency Analysis Module comprises a digital filter bank of filters, which decompose the signal of interest into separate frequency sub-bands.

6. The apparatus of claim 5, where the frequency sub-bands correspond to critical bands of hearing.

7. The apparatus of claim 3-4, where the Frequency Analysis Module is an FFT co-processor, which provides Fourier transform components of the signal of interest.

8. The apparatus of claim 5, where the frequency components are grouped together to approximate sub-bands correspond to critical bands of hearing.

9. The apparatus of claim 1 and 4, where the input device 203 allows the user to select a parameter b, which parameterizes the personalized sound adjustment model 206, thereby allowing the user to modify the output of the personalized sound adjustment model 206.

10. The apparatus of claims 1, 2 and 4, wherein the personalized sound adjustment model is a linear function of the critical band center frequency F, where the Linear Slope equation is

X₀=[F−

Y]×

b

where X₀ is the threshold elevation at the Frequency F, the parameter, b, adjustable by the user input parameter b, represents the slope of the line in dBHL/critical band, where Y is a value selected from a range of 2-3 Bark, and where F is the critical band center frequency.

11. The apparatus of claims 1, 2 and 4, wherein the personalized sound adjustment model is composed of a pattern library which is stored in long term memory, where the patterns are comprised of points which measure threshold elevations, X₀, with respect to frequency, of which 2/3 are within +/−

5 dBHL of a mean squared error linear fit to the pattern with respect to critical band center frequency, where the parameter b is used to select a pattern or interpolate between points in the pattern, and the frequency is used to select an element of the pattern or interpolate between elements, and where the user adjustable input (b) bears a monotonic relationship to the selected X₀ for each critical band center frequency.

12. The apparatus of claims 1, 2 and 4, wherein the personalized sound adjustment model is composed of a lookup table indexed by values of the parameter b and frequency, where the threshold elevation, X₀ is found by selecting the corresponding element of the lookup table or interpolating between points in the lookup table.

14. The apparatus of claim 3-4, wherein the corrective gains are computed in parallel for multiple channels using multiple processing units.

15. The apparatus of claim 3-4, wherein the apparatus includes a speaker and an amplifier for outputting the audio signal.

16. The apparatus, of claim 3 or 4 wherein the apparatus is a mobile phone, media player, headset, or virtual audio port.

17. The apparatus of claim 3 and 4, wherein the psychoacoustic model comprises a formula which computes the gain as a function of the signal and ambient noise levels which is needed to make the sound appear as loud as if the noise was not present, the formula comprising:

2. An apparatus 800, effective for measuring the power spectrum of the ambient noise in the environment of the listener where the apparatus calculates a plurality of spectrally varying threshold elevations across a plurality of channels, where the threshold elevations are derived from the power spectrum of the ambient noise, each of the threshold elevations being represented as X₀, in dBHL at a given frequency F, and where each of the threshold elevations can be used to determine corresponding correction gains, the apparatus comprising:

a microprocessor 801 configured to execute an application comprising a sound adjustment model 806, where the sound adjustment model 806 generates a spectrum of threshold elevations corresponding to a power spectrum of an ambient noise;

wherein the microprocessor 801 executes the personalized sound adjustment model 806 and generates a spectrum of threshold elevations corresponding a power spectrum of an ambient noise and where said threshold elevations are effective for determining appropriate gains to be applied to an audio signal of interest in order to correct the audio signal to account for the ambient noise.

13. The apparatus of claim 2, wherein the personalized sound adjustment model computes the threshold elevation by estimating a power spectrum of an ambient noise environment in which the user is situated.

4. An apparatus 200, effective for selecting a plurality of threshold elevations for a given user, without requiring individual measurement of each threshold elevation, and thereafter applying a plurality of correction gains to an audio signal where the gains correspond to the threshold elevations, where the threshold elevations are computed from a single parameter set by a user-adjustable input device 203, each of the threshold elevations being represented as X₀, in dBHL at a given frequency F, the apparatus comprising:

a. an audio device 202, configured to identify the audio signal x(t), where the audio signal is a broadband audio signal of interest, the audio device operatively connected to a microprocessor 201;

b. the input device 203, operatively connected to the microprocessor 201, controllable by a user, which allows the user to adjust a parameter;

c. the microprocessor 201, configured to execute applications for;

i. a frequency analysis module 204 configured to extract a plurality of frequency components from the audio signal;

ii. a kHz frequency to critical band center frequency converter component 205;

iii. a personalized sound adjustment model 206, parameterized by the user adjustable input 203 and the parameter, chosen by the user, which establishes threshold elevations per frequency component and where said threshold elevations are effective for users with impaired hearing or for users with normal hearing who wish to optimize their perceived hearing;

iv. a psychoacoustic model 207 which, using the threshold elevations for each frequency component, computes corresponding gains per each frequency component of the audio signal;

v. a gain block component 208 which applies gains to each frequency component of the audio signal;

vi. a frequency synthesis module 209 which reconstitutes the audio signal from the frequency components, with the correction gains;

whereupon, the audio device 202 extracts the audio signal x(t), which is then input to the microprocessor 201 through an analog to digital converter,

whereupon, the microprocessor 201 uses the frequency analysis module 204, to decompose the audio signal into a plurality of frequency components,

whereupon, for each component, the equivalent critical band center frequency F is computed 205,

whereupon, the personalized sound adjustment model 206 generates, for each frequency component, a threshold elevation value for X₀, using the user adjustable input 203 as a parameter b of the model,

whereupon the microprocessor 201 calculates, for each frequency component, a correction gain Δ

X for the audio signal, using the psychoacoustic model 207,

whereupon the microprocessor 201 applies the corrective gain to each frequency component of the audio signal 208,

whereupon the microprocessor 201 reconstitutes the corrected audio signal by summing the frequency components, producing x_out(t) 209.

18-39. -39. (canceled)