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US 10,241,581 B2Granted
RF-based micro-motion tracking for gesture tracking and recognition
AssigneesGoogle Inc., The Board of Trustees of the Lealand Stanford Junior University
InventorsJaime Lien, Erik M. Olson, Patrick M. Amihood, Ivan Poupyrev
Life of this patent
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Abstract
This document describes techniques for radio frequency (RF) based micro-motion tracking. These techniques enable even millimeter-scale hand motions to be tracked. To do so, radar signals are used from radar systems that, with conventional techniques, would only permit resolutions of a centimeter or more.
Claims20
A computer-implemented method comprising:
- receiving a radar signal representing a superposition of reflections of two or more points of a hand within a radar field provided by a radar system, a first of the two or more points having a first movement and a second of the two or more points having a second movement;
- determining a velocity profile from the radar signal, the velocity profile indicating energies at multiple velocities, a first of the energies representing a reflection of the first point of the hand having the first movement and a second of the energies representing a reflection of the second point of the hand having the second movement;
- extracting, from the velocity profile determined from the radar signal and one or more prior-determined or later-determined velocity profiles determined from radar signals over time, relative velocities between the first and second points of the hand;
- and
- determining a displacement trajectory by integrating the relative velocities between the first and second points of the hand, the displacement trajectory representing a relative displacement between the first and second points of the hand.
2 more elements
One or more non-transitory computer-readable storage media having instructions stored thereon that, responsive to execution by one or more computer processors, implement a micro-motion tracking module and a recognition module:
- the micro-motion tracking module configured to:
- receive a radar signal representing a superposition of reflections of two or more points of a hand within a radar field provided by a radar system, a first of the two or more points having a first movement and a second of the two or more points having a second movement;
- determine a velocity profile from the radar signal, the velocity profile indicating energies at multiple velocities, a first of the energies representing a reflection of the first point of the hand having the first movement and a second of the energies representing a reflection of the second point of the hand having the second movement;
- extract, from the velocity profile determined from the radar signal and one or more prior-determined or later-determined velocity profiles determined from radar signals over time, relative velocities between the first and second points of the hand;
- and
- determine a displacement trajectory by integrating the relative velocities between the first and second points of the hand, the displacement trajectory representing a relative displacement between the first and second points of the hand, and
- the recognition module configured to:
- determine, based on the displacement trajectory, a gesture of the first and second points of the hand;
- and
- pass the gesture effective to control or alter a display, function, or capability of a device.
7 more elements
An apparatus comprising:
- one or more computer processors;
- a radar system comprising:
- one or more radar-emitting elements configured to provide a radar field;
- and
- one or more antenna elements configured to receive a radar signal representing a superposition of reflections of two or more points of a hand within the radar field;
- and
- one or more computer-readable storage media having instructions stored thereon that, responsive to execution by the one or more computer processors, implement a micro-motion tracking module and a recognition module:
- the micro-motion tracking module configured to:
- receive the radar signal representing the superposition of reflections of the two or more points of the hand within the radar field provided by the radar system, a first of the two or more points having a first movement and a second of the two or more points having a second movement;
- determine a velocity profile from the radar signal, the velocity profile indicating energies at multiple velocities, a first of the energies representing a reflection of the first point of the hand having the first movement and a second of the energies representing a reflection of the second point of the hand having the second movement;
- extract, from the velocity profile determined from the radar signal and one or more prior-determined or later-determined velocity profiles determined from radar signals over time, relative velocities between the first and second points of the hand;
- and
- determine a displacement trajectory by integrating the relative velocities between the first and second points of the hand, the displacement trajectory representing a relative displacement between the first and second points of the hand, and
- the recognition module configured to:
- determine, based on the displacement trajectory, a gesture of the first and second points of the hand;
- and
- pass the gesture to an application of the apparatus or a remote or peripheral device effective to control or alter a display, function, or capability of the apparatus or the remote or peripheral device.
14 more elements
Dependencies are inferred from the claim text.