Enhancing audio using a mobile device

• US 9,706,305 B2
• Filed: 05/17/2016
• Issued: 07/11/2017
• Est. Priority Date: 08/01/2013
• Status: Active Grant

• Current Assignee: Caavo Inc
• Original Assignee: Caavo Inc
• Inventors: Aggarwal, Ashish Dharmpal, Satheesh, Sharath Hariharpur
• Primary Examiner(s): Nguyen, Khai N
• Application Number:
  US15/157,135
• Publication Number:
  US 20160261953A1
• Time in Patent Office: 420 Days
• Field of Search: 381 941, 381 942, 381 95, 381 96, 381 99, 381103
• CPC Class Codes: G06F 3/165 Management of the audio stream, e.g. setting of volume, audio stream path
• CPC Class Codes: G10L 21/0232 Processing in the frequency domain
• CPC Class Codes: G10L 25/51 for comparison or discrimination
• CPC Class Codes: H03G 3/20 Automatic control H03G3/005 takes precedence; combined with volume compression or expansion H03G7/00
• CPC Class Codes: H03G 3/3005 in amplifiers suitable for low-frequencies, e.g. audio amplifiers H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level
• CPC Class Codes: H03G 5/005 of digital signals
• CPC Class Codes: H03G 5/165 Equalizers; Volume or gain control in limited frequency bands
• CPC Class Codes: H03G 7/002 in untuned or low-frequency amplifiers, e.g. audio amplifiers H03G7/007, H03G7/001, H03G7/008, H03G7/02, H03G7/06 take precedence
• CPC Class Codes: H03H 17/04 Recursive filters
• CPC Class Codes: H03H 2017/0472 based on allpass structures
• CPC Class Codes: H04R 1/08 Mouthpieces; Microphones; Attachments therefor
• CPC Class Codes: H04R 2430/01 Aspects of volume control, not necessarily automatic, in sound systems
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 25/50 Customised settings for obtaining desired overall acoustical characteristics
• CPC Class Codes: H04R 25/505 using digital signal processing
• CPC Class Codes: H04R 29/00 Monitoring arrangements; Testing arrangements for hearing aids H04R25/30; detection of loudspeaker connection H04R5/04; sound-field adaptation dependent on speaker detection H04S7/308
• CPC Class Codes: H04R 29/001 for loudspeakers H04R29/007 takes precedence
• CPC Class Codes: H04R 29/004 for microphones H04R29/007 takes precedence
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones
• CPC Class Codes: H04R 3/04 : for correcting frequency response

Abstract

Embodiments disclosed herein enable detection and improvement of the quality of the audio signal using a mobile device by determining the loss in the audio signal and enhancing audio by streaming the remainder portion of audio. Embodiments disclosed herein enable an improvement in the sound quality rendered by rendering devices by emitting an test audio signal from the source device, measuring the test audio signal using microphones, detecting variation in the frequency response, loudness and timing characteristics using impulse responses and correcting for them. Embodiments disclosed herein also compensate for the noise in the acoustic space by determining the reverberation and ambient noise levels and their frequency characteristics and changing the digital filters and volumes of the source signal to compensate for the varying noise levels.

Claims

1. A method, performed by a mobile device, for improving quality of an audio signal being played back by an audio system that includes a source device and at least one rendering device, the method comprising:

detecting a period of silence in the audio signal;

measuring ambient noise characteristics of an acoustic space responsive to detecting the period of silence;

calculating a frequency response of the ambient noise characteristics;

calculating a digital filter based on the calculated frequency response; and

communicating the digital filter to the source device, the source device being configured to perform adjustments to improve the audio signal based on the digital filter.

2. The method of claim 1, wherein the ambient noise characteristics comprise frequency characteristics and a loudness level of noise during the period of silence.

3. The method of claim 2, wherein the loudness level is measured using a weighting filter based at least on A-weights or C-weights.

4. The method of claim 2, further comprising:

estimating a volume level of the audio signal based on the loudness level; and

communicating settings related to the volume level to the source device.

5. The method of claim 1, wherein the calculating the frequency response of the ambient noise characteristics comprises calculating the frequency response using a Fast Fourier Transform (FFT) of the ambient noise characteristics.

6. The method of claim 1, wherein the calculating the digital filter based on the calculated frequency response comprises calculating the digital filter using an inverse of the calculated frequency response.

7. The method of claim 1, wherein the digital filter is a least one of an infinite impulse response filter or a finite impulse response filter.

8. A computer program product comprising computer executable program code recorded on a computer readable non-transitory storage medium, said computer executable program code when executed, performing a method for improving quality of an audio signal being played back on an audio system that includes a source device and at least one rendering device, the method comprising:

detecting a period of silence in the audio signal;

measuring ambient noise characteristics of an acoustic space responsive to detecting the period of silence;

calculating a frequency response of the ambient noise characteristics;

calculating a digital filter based on the calculated frequency response; and

communicating the digital filter to the source device, the source device being configured to perform adjustments to improve the audio signal based on the digital filter.

9. The computer program product of claim 8, wherein the ambient noise characteristics comprise frequency characteristics and a loudness level of noise during the period of silence.

10. The computer program product of claim 9, wherein the loudness level is measured using weighting filter based at least on A-weights or C-weights.

11. The computer program product of claim 9, further comprising:

estimating a volume level of the audio signal based on the loudness level; and

communicating settings related to the volume level to the source device.

12. The computer program product of claim 8, wherein the calculating the frequency response of the ambient noise characteristics comprises calculating the frequency response using a Fast Fourier Transform (FFT) of the ambient noise characteristics.

13. The computer program product of claim 8, wherein the calculating the digital filter based on the calculated frequency response comprises calculating the digital filter using an inverse of the calculated frequency response.

14. A mobile device configured to obtain a digital filter for improving quality of an audio signal being played back by an audio system that includes a source device and at least one rendering device, comprising:

at least one microphone configured to detect the audio signal; and

a processing unit configured to;

detect a period of silence in the detected audio signal;

measure ambient noise characteristics of an acoustic space responsive to detecting the period of silence;

calculate a frequency response of the ambient noise characteristics;

calculate a digital filter based on the calculated frequency response; and

communicate the digital filter to the source device, the source device being configured to perform adjustments to improve the audio signal based on the digital filter.

15. The mobile device of claim 14, wherein the ambient noise characteristics comprise frequency characteristics and a loudness level of noise during the period of silence.

16. The mobile device of claim 15, wherein the loudness level is measured using weighting filter based at least on A-weights or C-weights.

17. The mobile device of claim 14, wherein the processing unit is further configured to:

estimate a volume level of the detected audio signal based on the loudness level; and

communicate settings related to the volume level to the source device.

18. The mobile device of claim 14, wherein the processing unit is further configured to:

calculate the frequency response of the ambient noise characteristics using a Fast Fourier Transform (FFT) of the ambient noise characteristics.

19. The mobile device of claim 14, wherein the processing unit is further configured to:

calculate the digital filter using an inverse of the calculated frequency response.

20. The mobile device of claim 14, wherein the digital filter is a least one of an infinite impulse response filter or a finite impulse response filter.