Proximity detecting apparatus and method based on audio signals

1. An apparatus comprising:

at least one processor; and

at least one memory including computer code, the at least one memory and the computer code configured, with the at least one processor, to cause the apparatus to:

transmit from a first speaker a first audio signal;

transmit from a second speaker a second audio signal;

receive at least one audio signal using at least one microphone, wherein the at least one audio signal comprises a combination of a direct pathway and a reflected pathway first and second audio signals;

determine a distance value based on the received at least one audio signal; and

determine a presence of an object from the distance value.

2. The apparatus as claimed in claim 1 , wherein determine a presence of an object comprises:

determine at least one impulse response model;

determine an object reflection delay value; and

determine an object reflection distance based on the object reflection delay value.

3. The apparatus as claimed in claim 2 , wherein determine a presence of an object further comprises:

determine the object reflection distance is less than a first defined value; and

control a function of the apparatus dependent on the determined object reflection distance.

4. The apparatus as claimed in claim 3 , wherein control a function of the apparatus comprises at least one of:

control a speaker output level; and

wake the apparatus from standby.

5. The apparatus as claimed in claim 2 , wherein determine at least one impulse response model comprises determine at least two distinguishable signal impulse models, and wherein determine a presence of an object from the at least one impulse model comprises:

determine an object reflection delay value for each impulse model;

determine an object location based on the object reflection delay value for each impulse model; and

determine a motion of the object based on the determined object location.

6. The apparatus as claimed in claim 2 , wherein determine the at least one impulse response model comprises:

transform the at least one audio signal into a sparse representation domain; and

sparse sense the at least one audio signal in the sparse representation domain to determine the impulse response model.

7. The apparatus as claimed in claim 6 , wherein transform the at least one audio signal into the sparse representation domain comprises at least one of:

cross-correlate the at least one audio signal against a reference signal; and

frame the at least one audio signal before the at least one audio signal is cross-correlated.

8. The apparatus as claimed in claim 6 , wherein sparse sense comprises at least one of:

discrete Fourier transform the cross-correlated at least one audio signal;

organize the discrete Fourier transform products into a Toeplitz form;

determine the annihilating filter roots associated with the Toeplitz form discrete Fourier transform products; and

determine the impulse response model pulse times and amplitudes based on the annihilating filter root values.

9. The apparatus as claimed in claim 8 , wherein the at least one memory and the computer code are further configured, with the at least one processor, to cause the apparatus to:

denoise the Toeplitz form discrete Fourier transform products before determining the annihilating filter roots.

10. A method comprising:

transmitting from a first speaker a first audio signal;

transmitting from a second speaker a second audio signal;

receiving at least one audio signal using at least one microphone, wherein the at least one audio signal comprises combination of a direct pathway and a reflected pathway first and second audio signals;

determining a distance value based on the received at least one audio signal; and

determining a presence of an object from the distance value.

11. The method as claimed in claim 10 , wherein determining a presence of an object comprises:

determining at least one impulse response model;

determining an object reflection delay value; and

determining an object reflection distance based on the object reflection delay value.

12. The method as claimed in claim 11 , wherein determining a presence of an object further comprises:

determining the object reflection distance is less than a first defined value; and

controlling a function of an apparatus dependent on determining the object reflection distance.

13. The method as claimed in claim 12 , wherein controlling a function of an apparatus comprises at least one of:

controlling a speaker output level; and

waking the apparatus from standby.

14. The method as claimed in claim 11 , wherein determining at least one impulse response model comprises determining at least two distinguishable signal impulse models, and wherein determining a presence of an object from the at least one impulse model comprises:

determining an object reflection delay value for each impulse model;

determining an object location based on the object reflection delay value for each impulse model; and

determining a motion of the object based on determining object locations.

15. The method as claimed in claim 11 , wherein determining the at least one impulse response model comprises:

transforming the at least one audio signal into a sparse representation domain; and

sparse sensing the at least one audio signal in the sparse representation domain to determine the impulse response model.

16. The method as claimed in claim 15 , wherein transforming the at least one audio signal into the sparse representation domain comprises at least one of:

cross-correlating the at least one audio signal against a reference signal; and

framing the at least one audio signal before cross-correlating.

17. The method as claimed in claim 15 , wherein sparse sensing comprises at least one of:

discrete Fourier transforming the cross-correlated at least one audio signal;

organizing the discrete Fourier transform products into a Toeplitz form;

determining the annihilating filter roots associated with the Toeplitz form discrete Fourier transform products; and

determining the impulse response model pulse times and amplitudes based on the annihilating filter root values.

18. The method as claimed in claim 17 , further comprising:

denoising the Toeplitz form discrete Fourier transform products before determining the annihilating filter roots.