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US 2019/0155396 A1Published application
RF-Based Micro-Motion Tracking for Gesture Tracking and Recognition
AssigneesGoogle Inc., The Board of Trustees of the Leland 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
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 first radar signal representing reflections of a radar field off first and second points of a hand at a first time, the first and second points of the hand moving relative to one another within the radar field;
- determine, based on energies of the first radar signal, velocities of the first and second points of the hand at the first time;
- receive a second radar signal representing reflections of the radar field off the first and second points of the hand at a second time;
- determine, based on energies of the second radar signal, velocities of the first and second points of the hand at the second time;
- calculate, based on the velocities of the first and second points of the hand at the first and second times, a relative velocity between the first and second point of the hand;
- and
- determine, based on the relative velocity between the first and second point of the hand and an elapsed time between the first and second times, a millimeter-scale change in displacement between the first and second points of the hand;
- and
- the recognition module configured to:
- determine, based on the change in displacement, 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.
10 more elements
A computer-implemented method comprising:
- receiving a first radar signal representing reflections of a radar field off first and second points of a hand at a first time, the first and second points of the hand moving relative to one another within the radar field;
- determining, based on energies of the first radar signal, velocities of the first and second points of the hand at the first time;
- receiving a second radar signal representing reflections of the radar field off the first and second points of the hand at a second time;
- determining, based on energies of the second radar signal, velocities of the first and second points of the hand at the second time;
- calculating, based on the velocities of the first and second points of the hand at the first and second times, a relative velocity between the first and second points of the hand;
- and
- determining, based on the relative velocity between the first and second points of the hand and an elapsed time between the first and second times, a millimeter-scale change in displacement between the first and second points of the hand.
4 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 radar signals representing reflections of the radar field off two or more points of a hand that are moving relative to one another 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:
- cause the radar-emitting elements to provide the radar field;
- receive a first radar signal from the antenna elements representing reflections of the radar field off the first and second points of a hand at a first time;
- determine, based on energies of the first radar signal, velocities of the first and second points of the hand at the first time;
- receive a second radar signal from the antenna elements representing reflections of the radar field off the first and second points of the hand at a second time;
- determine, based on energies of the second radar signal, velocities of the first and second points of the hand at the second time;
- calculate, based on the velocities of the first and second points of the hand at the first and second times, a relative velocity between the first and second point of the hand;
- and
- determine, based on the relative velocity between the first and second point of the hand and an elapsed time between the first and second times, a millimeter-scale change in displacement between the first and second points of the hand;
- and
- the recognition module configured to:
- determine, based on the change in displacement, 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.
18 more elements
Dependencies are inferred from the claim text.