US 12,615,473 B1Granted

Device-specific calibration for ultrasound emissions

AssigneeAmazon Technologies, Inc.

InventorsKrishna Kamath Koteshwara, Chad A. Jackman, Trausti Thor Kristjansson

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Abstract

Techniques for calibrating user devices to account for device-specific factors that can affect the user devices' abilities to detect user movement. User devices detect user movement by emitting ultrasonic signals, and characterizing changes in signal characteristics of reflections of the ultrasonic signals off the person caused by the movement of the person. Device-specific factors may negatively affect the ability of the user devices to detect user movement. To account for these factors, device-specific frequency responses for each device may be determined across bandwidths in an ultrasonic frequency range, and the device-specific calibration data may be stored on each user device. Upon being placed in user environments, the user devices emit ultrasonic sweep signals that span the different bandwidths in the ultrasonic frequency range to determine environmental factors. The user devices may use the device-specific and environmental factors to determine optimal carrier frequencies and gain values for subsequent ultrasonic signal transmissions.

Claims20

Dependent claims

A user device comprising:

a loudspeaker;
a microphone;
memory storing:
a first gain value that is associated with a first frequency response of the user device in a first ultrasonic frequency range;
and
a second gain value that is associated with a second frequency response of the user device in a second ultrasonic frequency range;
and
one or more processors;
and
one or more computer-readable media storing computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
causing the loudspeaker to emit, during a first period of time, an ultrasonic sweep signal into an environment of the user device, the ultrasonic sweep signal being emitted at different frequencies in an overall ultrasonic frequency range, the overall ultrasonic frequency range including the first and second ultrasonic frequency ranges;
generating, at least partly using the microphone, first data representing a noise signal in the environment and reflection signals associated with reflections of the ultrasonic sweep signal off objects in the environment;
stopping emission of the ultrasonic sweep signal for a second period of time;
receiving, during the second period of time, the noise signal at the microphone;
generating, at least partly using the microphone, second data representing the noise signal;
determining, using the first data, the second data, and the first gain value, a first signal-to-noise ratio (SNR) value for the first ultrasonic frequency range;
determining, using the first data, the second data, and the second gain value, a second SNR value for the second ultrasonic frequency range;
determining that the first SNR value is greater than the second SNR value;
and
causing the loudspeaker to emit an ultrasonic signal at a carrier frequency that is within the first ultrasonic frequency range.

17 more elements

A computer-implemented method comprising:

emitting, by a computing device and during a first period of time, an ultrasonic sweep signal into an environment, the ultrasonic sweep signal being emitted at different frequencies within a frequency range;
generating, by the computing device and during the first period of time, first data representing reflected signals and a noise signal, the reflected signals corresponding to the ultrasonic sweep signal;
generating, by the computing device and during a second period of time, second data representing the noise signal;
identifying a first gain value associated with a first frequency response of the computing device emitting ultrasonic signals in a first frequency range that is within the frequency range;
determining, using the first data and the first gain value, a first signal-to-noise ratio (SNR) value for the first frequency range;
identifying a second gain value associated with a second frequency response of the computing device emitting ultrasonic signals in a second frequency range that is within the frequency range;
determining, using the first data and the second gain value, a second SNR value for the second frequency range;
determining that the first SNR value is greater than the second SNR value;
and
emitting, by the computing device, an ultrasonic signal at a carrier frequency that is within the first frequency range.

7 more elements

A computing device comprising:

a loudspeaker;
a microphone;
one or more processors;
and
one or more computer-readable media storing computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
storing a first gain value associated with a first frequency response of the computing device emitting ultrasonic signals in a first ultrasonic frequency range;
storing a second gain value associated with a second frequency response of the computing device emitting ultrasonic signals in a second ultrasonic frequency range;
emitting, by the loudspeaker, an ultrasonic sweep signal into an environment, the ultrasonic sweep signal being emitted at least in the first frequency range and the second frequency range;
generating, at least partly using the microphone, first data representing reflected signals corresponding to the ultrasonic sweep signal;
receiving, from an application running on the computing device, an indication of a particular ultrasonic frequency range in which the application emits ultrasonic signals;
determining, using the first data, a first signal-metric value for the first ultrasonic frequency range, the first ultrasonic frequency range corresponding to the particular ultrasonic frequency range;
determining, using the first data, a second signal-metric value for the second ultrasonic frequency range, the second ultrasonic frequency range corresponding to the particular ultrasonic frequency range;
selecting, based at least in part on the first and second signal-metric values, the first ultrasonic frequency range;
determining, using the first gain value, an third gain value at which to emit an ultrasonic signal in the first ultrasonic frequency range;
and
emitting, by the loudspeaker, an ultrasonic signal using the third gain value and at a carrier frequency that is within the first ultrasonic frequency range.

13 more elements

Dependencies are inferred from the claim text.