Method of Temporal Segmentation of an Instrumented Gesture, Associated Device and Terminal

• US 20140232642A1
• Filed: 02/17/2014
• Published: 08/21/2014
• Est. Priority Date: 02/15/2013
• Status: Active Grant

• Current Assignee: Orange S.A.
• Original Assignee: Orange S.A.
• Inventors: Lefebvre, Gregoire, Roux, Sebastien, Petit, Eric
• Granted Patent: US 10,078,373 B2
• Time in Patent Office: Days
• US Class Current: 345/156
• CPC Class Codes: G06F 1/1694 the I/O peripheral being a single or a set of motion sensors for pointer control or gesture input obtained by sensing movements of the portable computer
• CPC Class Codes: G06F 2200/1637 Sensing arrangement for detection of housing movement or orientation, e.g. for controlling scrolling or cursor movement on the display of an handheld computer
• CPC Class Codes: G06F 3/017 Gesture based interaction, e.g. based on a set of recognized hand gestures interaction based on gestures traced on a digitiser G06F3/04883
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry

Abstract

Temporally segmenting an instrumented gesture executed by a user with a terminal having an inertial navigation module, which measures a vector of inertial characteristics representative of movement of the terminal. Segmenting includes, at each current instant: calculating an instantaneous power value of the vector; estimating a gesture indicator based on variation between the instantaneous power value and a mean power value estimated over a preceding time window; determining a start of gesture at a first instant, when the estimated gesture indicator is greater than or equal to a first threshold during a time interval greater than or equal to a first interval; and determining an end of gesture at a second instant when, at the current instant, the estimated gesture indicator is less than or equal to a second threshold during a time interval greater than or equal to a second time interval.

Claims

1. A method of temporal segmentation of an instrumented gesture in the course of execution by a user with the aid of a terminal equipped with an inertial navigation module, able to measure, during the execution of the gesture, a vector of inertial characteristics {right arrow over (V)} representative of a movement of said terminal, wherein said method comprises the following steps, implemented at each current instant (t_n):

calculation of an instantaneous power value (P(t_n)) of said vector {right arrow over ((V)}(t_n)) at the current instant;

estimation of a gesture indicator (I(t_n)) on the basis of a variation between said instantaneous power value and a mean power value estimated over a time window (F[t₀,t_n]) preceding the current instant;

determination of a first instant (t_n1), termed start of gesture, corresponding to the current instant, when the estimated gesture indicator takes a value greater than or equal to a first predetermined threshold during a time interval greater than or equal to a first predetermined interval;

subsequent to the detection of a start of gesture at the first current instant (t_n1), determination of a second instant (t_n2), termed end of gesture when, at the current instant, the estimated gesture indicator takes a value less than or equal to a second predetermined threshold during a time interval greater than or equal to a second predetermined time interval.

2. The method of temporal segmentation of an instrumented gesture according to claim 1, wherein the method comprises a step of positive decision of segmentation of a gesture when the first and the second current instants (t_n1, t_n2) are separated by a time interval greater than a third predetermined threshold.

3. The method of temporal segmentation of an instrumented gesture according to one of claim 1, wherein estimating a gesture indicator comprises estimation of a first estimator of mean power of the instantaneous powers over said window, said instantaneous powers being weighted according to a first weighting, estimation of a second estimator of mean power of the instantaneous powers over said window, said instantaneous powers being weighted according to a second weighting, and calculation of the gesture indicator as a function of the absolute value of the difference between the estimated values of the first and of the second estimator.

4. The method of temporal segmentation of an instrumented gesture according to claim 3, wherein the second weighting applies a higher weight to the instantaneous power value calculated at the current instant (t_n) than the first weighting.

5. The method of temporal segmentation of an instrumented gesture according to claim 3, wherein the first and the second estimators are calculated in a recursive manner on the basis of the value estimated at the previous instant (t_n−

1) and of the instantaneous power value (P(t_n)) calculated at the current instant (t_n).

6. The method of temporal segmentation of an instrumented gesture according to claim 1, wherein the method comprises initializing the step of estimating the gesture indicator, at an initial instant (t₀), whose value belongs to the group consisting of:

an instant of power-up of the terminal equipment;

an instant of launching of a predetermined application;

the current instant (t_n) decreased by a predetermined time-window size.

7. The method of temporal segmentation of an instrumented gesture according to claim 1, wherein subsequent to the determination of a second instant (t_n2) of end of gesture, the method triggers a validation step comprising the following sub-steps of:

calculation of a measure of inertial variation between the instantaneous values of the vector of inertial characteristics at the current instant (t_n) and of the estimated mean values of said characteristics over a time window (F[t₀,t_n]) preceding the current instant;

comparison of the calculated variation value with a predetermined threshold during a predetermined time interval;

validation of the instant (t_n2) of end of gesture determined when the calculated measure is less than said threshold at least during the predetermined time interval.

8. A device for temporal segmentation of an instrumented gesture in the course of execution by a user with the aid of a terminal equipped with an inertial navigation module, able to measure, during the execution of the gesture, a vector of inertial characteristics representative of a movement of said terminal, wherein the device comprises the following modules, implemented at each current instant:

a module configured to calculate an instantaneous power value of said vector {right arrow over (V)}(t_n)) at the current instant;

a module configured to estimate of a gesture indicator (I(t_n)) on the basis of a variation between said instantaneous power value and a mean power value estimated over a time window (F(t₀,t_n)) preceding the current instant;

a module configured to determine first instant (t_n1), termed start of gesture, corresponding to the current instant, when the estimated gesture indicator takes a value greater than or equal to a first predetermined threshold during a time interval greater than or equal to a first predetermined interval;

a module configured to, subsequent to the detection of a start of gesture at the first current instant (t_n1), determine a second instant (t_n2), termed end of gesture when, at the current instant, the estimated gesture indicator takes a value less than or equal to a second predetermined threshold during a time interval greater than or equal to a second predetermined time interval.

9. The device of claim 8, wherein the device is implemented within the terminal, which is equipped with an inertial navigation module (NAV) configured to measure, during the execution of a gesture, a vector {right arrow over (V)}(t_n)) of the inertial characteristics representative of the movement of said terminal.

10. A non-transitory computer-readable medium comprising a computer program recorded thereon and comprising instructions for implementation of a method of temporal segmentation of an instrumented gesture in the course of execution by a user with the aid of a terminal equipped with an inertial navigation module, able to measure, during the execution of the gesture, a vector of inertial characteristics {right arrow over (V)} representative of a movement of said terminal, when the instructions are executed by a processor, wherein the method comprises the following steps, implemented at each current instant (t₀):

calculation of an instantaneous power value (P(t_n)) of said vector {right arrow over ((V)}(t_n)) at the current instant;

estimation of a gesture indicator I(t_n)) on the basis of a variation between said instantaneous power value and a mean power value estimated over a time window (F[t₀,t_n]) preceding the current instant;

determination of a first instant (t_n1), termed start of gesture, corresponding to the current instant, when the estimated gesture indicator takes a value greater than or equal to a first predetermined threshold during a time interval greater than or equal to a first predetermined interval;

subsequent to the detection of a start of gesture at the first current instant (t_n1), determination of a second instant (t_n2), termed end of gesture when, at the current instant, the estimated gesture indicator takes a value less than or equal to a second predetermined threshold during a time interval greater than or equal to a second predetermined time interval.

11. (canceled)