Using ultrasound to detect an environment of an electronic device
In one embodiment, a method includes transmitting, from a first transducer of an electronic device, a first audio signal to a surface near the electronic device. The first audio signal is generated based on a frequency sweep across a range of frequencies. The method also includes receiving, at a second transducer of the electronic device, a second audio signal that is at least partly reflected off the surface. The method then determines an attribute of the surface based on the received second audio signal.
1. A method comprising:
transmitting, from a first transducer of an electronic device, a first audio signal to a surface near the electronic device, wherein the first audio signal is generated based on a frequency sweep across a range of frequencies;
receiving, at a second transducer of the electronic device, a second audio signal, wherein at least part of the second audio signal is reflected off the surface; and
determining, based on the received second audio signal, an attribute of the surface based on a comparison of amplitudes of the received second audio signal at a plurality of frequencies to frequency signatures corresponding to attributes of objects.
2. The method of claim 1 , wherein the range of frequencies includes ultrasonic frequencies.
3. The method of claim 2 , wherein there is no ultrasonic couplant between the first transducer and the surface.
4. The method of claim 1 , wherein the range of frequencies comprises frequencies in a range of 18 kHz to 24 kHz.
5. The method of claim 1 , wherein:
the range of frequencies comprises a plurality of subranges; and
the method further comprises tuning, based on the received second audio signal, the first transducer to transmit at one or more of the plurality of subranges.
6. The method of claim 1 , wherein:
the first transducer comprises a speaker; and
the second transducer comprises a microphone.
7. The method of claim 1 , wherein the first transducer is the second transducer.
8. The method of claim 1 wherein:
at least part of the second audio signal is a result of coupling between the first transducer and the second transducer; and
determining, based on the received second audio signal, the attribute of the surface comprises determining the attribute of the surface based at least on:
the part of the second audio signal that is the result of coupling between the first transducer and the second transducer; and
the part of the second audio signal that is reflected off the surface.
9. The method of claim 1 , wherein determining, based on the received second audio signal, the attribute of the surface comprises:
analyzing the received second audio signal in a frequency space;
dividing the frequency space into a plurality of bins, each bin corresponding to a frequency band;
comparing an amplitude of the received second audio signal in one or more of the plurality of bins to one or more corresponding bins in a signature, each signature corresponding to one or more acoustic properties of one or more objects; and
determining, based on the comparison, the attribute of the surface.
10. The method of claim 1 , wherein determining, based on the received second audio signal, the attribute of the surface comprises:
determining, by a machine-learning classifier, one or more attributes of the received second audio signal; and
associating the one or more attributes of the received second audio signal with the attribute of the surface.
11. The method of claim 10 , wherein associating the one or more attributes of the received second audio signal with the attribute of the surface comprises receiving, from a user of the electronic device, an identification of the attribute of the surface.
12. The method of claim 10 , wherein associating the one or more attributes of the received second audio signal with the attribute of the surface comprises accessing, from a database of signatures, an identification of the attribute of the surface associated with a signature corresponding to the one or more attributes of the received second audio signal, wherein each signature corresponds to one or more acoustic properties of one or more objects.
13. The method of claim 1 , wherein determining the attribute of the surface comprises determining a type of material of the surface.
14. The method of claim 1 , further comprising determining, based on the attribute of the surface, a context of the electronic device.
15. The method of claim 14 , wherein:
the electronic device comprises one or more sensors; and
the context of the device is determined based on output from at least one of the sensors and the attribute of the surface.
16. The method of claim 14 , wherein the context comprises a location of the electronic device.
17. The method of claim 16 , further comprising enabling or disabling, based on the location of the electric device, one or more functionalities of the electronic device.
18. The method of claim 17 , wherein the functionality comprises a functionality of an application on the electronic device.
19. The method of claim 17 , wherein the functionality comprises a particular mode of the electronic device.
20. The method of claim 1 , wherein determining the attribute of the surface comprises determining the presence of an object comprising the surface.
21. The method of claim 20 , further comprising determining, based on the received second audio signal, a distance between the object and the electronic device.
22. The method of claim 1 , wherein determining the attribute of the surface comprises identifying an object comprising the surface.
23. An apparatus comprising:
a first transducer;
a second transducer; and
one or more non-transitory storage media embodying instructions and one or more processors operable to execute the instructions to:
initiate transmission, from the first transducer, of a first audio signal to a surface near the apparatus, wherein the first audio signal is generated based on a frequency sweep across a range of frequencies;
process a second audio signal, wherein the second audio signal is received by the second transducer and at least part of the second audio signal is reflected off the surface; and
determine, based on the second audio signal, an attribute of the surface based on a comparison of amplitudes of the received second audio signal at a plurality of frequencies to frequency signatures corresponding to attributes of objects.
24. One or more non-transitory computer-readable storage media embodying instructions that when executed by one or more processors cause the one or more processors to:
initiate transmission, from a first transducer of an electronic device, of a first audio signal to a surface near the apparatus, wherein the first audio signal is generated based on a frequency sweep across a range of frequencies;
process a second audio signal, wherein the second audio signal is received by a second transducer of the electronic device and at least part of the second audio signal is reflected off the surface; and
determine, based on the second audio signal, an attribute of the surface based on a comparison of amplitudes of the received second audio signal at a plurality of frequencies to frequency signatures corresponding to attributes of objects.