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1. (WO2016107653) SYSTEM AND METHOD FOR MONITORING THE MOVEMENT OF A PART OF A HUMAN BODY
Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

CLAIMS

A method for monitoring the movement of a part of a human body (2), said movement comprising a number N of iterations of a rotation of said part of said human body (2) in a plane (xy), said method comprising:

providing data indicative of said movement of said part of said human body (2);

processing said data so as to generate a rotation signal (0(t)) indicative of said rotation of said part of a human body in said plane (xy); and

identifying a portion of said rotation signal (0(t)) corresponding to a respective iteration of said rotation of said part of said human body in said plane (xy) by determining a start time (ts), an end time (tE) and a peak time (tP) of said respective iteration;

said determining comprising:

determining a plurality of null-velocity instants (t*) wherein an angular velocity of said part of said human body (2) in said plane (xy) is substantially null;

determining, amongst said plurality of null-velocity instants (t*), a set of candidate start/end times and a set of candidate peak times on the basis of at least one condition on relative values of said rotation signal (0(t)) in correspondence of said plurality of null-velocity instants (t*); and

determining said start time (ts), said end time (tE) and said peak time (tP) as a combination of two candidate start/end times and a candidate peak time that fulfils at least one condition on values of said rotation signal (0(t)) in correspondence of said candidate start/end times and said candidate peak times.

The method according to claim 1 , wherein said data comprise:

- first inertial data provided by an accelerometer of a sensing device (1 ) cooperating with said part of said human body;

- second inertial data provided by a gyroscope of said sensing device (1 ); and

- magnetic data provided by a magnetometer of said sensing device (1 )- The method according to claim 2, wherein it comprises:

if a norm of an acceleration detected by said accelerometer is lower than a predetermined threshold, processing said first inertial data and said magnetic data to generate said rotation signal (0(t)); and if a norm of an acceleration detected by said accelerometer is higher than said predetermined threshold, processing said second inertial data to generate said rotation signal (0(t)).

The method according to any of the preceding claims, wherein said processing said data so as to generate said rotation signal (0(t)) comprises filtering said data through an orientation estimation filter providing as output a 4-dimensional array representing an orientation of said sensing device (1 ) in a 3D space, and deriving said rotation signal (0(t)) from said 4-dimensional array.

The method according to any of the preceding claims, wherein said determining said set of candidate start/end times and said set of candidate peak times comprises classifying each null-velocity instant (t*(i)) as either a candidate start/end time or a candidate peak time by comparing the value of said rotation signal (0(t)) in correspondence of said null-velocity instant (t*(i)) to be classified with the value of said rotation signal (0(t)) in correspondence of a further null-velocity instant (t*(i-1 ), t*(i+1 )) preceding or succeeding said null-velocity instant (t*(i)) to be classified.

The method according to claim 5, wherein said determining said set of candidate peak times amongst said plurality of null-velocity instants

(t*) comprises classifying said null-velocity instant (t*(i)) as a candidate peak time if 0(t*(i))>0(t*(i-1 )) and 0(t*(i))>0(t*(i+1 )).

7. The method according to claim 5 or 6, wherein said determining said set of candidate start/end times amongst said plurality of null-velocity instants (t*) comprises classifying said null-velocity instant (t*(i)) as a candidate start/end time if:

0(t*(i))<0(t*(i+1 ), in case said null-velocity instant (t*(i)) is the first null-velocity instant identified subsequently to a last determined end time;

0(t*(i))<0(t*(i-1 )), in case said null-velocity instant (t*(i)) is the last null-velocity instant identified; and

- 0(t*(i))<0(t*(i-1 )) and 0(t*(i))<0(t*(i+1 )) for any other null-velocity instant (t*(i)).

8. The method according to any of the preceding claims, wherein said determining said start time (ts), said end time (tE) and said peak time (tP) comprises finding a combination of two candidate start/end times and a candidate peak time whose chronological order is such that said peak time (tP) lies between said start time (ts) and said end time (tE).

9. The method according to claim 8, wherein said determining said start time (ts), said end time (tE) and said peak time (tp) comprises finding a combination of two candidate start/end times and a candidate peak time which fulfils the following condition:


where c1 is a first threshold.

10. The method according to claim 9, wherein said determining said start time (ts), said end time (tE) and said peak time (tp) comprises finding a combination of two candidate start/end times which fulfils the following condition:

(e(ts)-e(tE )) < c2

where c2 is a second threshold.

1 1 . The method according to any of the preceding claims, wherein said identifying a portion of said rotation signal (0(t)) corresponding to a respective iteration of said rotation of said part of said human body (2) in said plane (xy) is started while said respective iteration is being executed by said part of said human body (2), after the end time for the iteration preceding said respective iteration has been determined.

12. The method according to claim 1 1 , wherein:

said determining said plurality of null-velocity instants (t*) comprises forming a set of null-velocity instants (t*) subsequent to said end time of said preceding iteration, and updating it by adding thereto each new null-velocity instant (t*) subsequent to said end time of said preceding iteration, when said new null-velocity instant (t*) is identified;

said determining said set of candidate start/end times and said set of candidate peak times comprises classifying said new null- velocity instant (t*) as a candidate start/end time or as a candidate peak time, when said new null-velocity instant (t*) is identified; and said determining said start time (ts), said end time (.E) and said peak time (tp) comprises seeking for said combination of two candidate start/end times and one candidate peak time which fulfils said at least one condition, when said new null-velocity instant (t*) is classified as either a candidate start/end time or a candidate peak time.

13. The method according to claim 1 2 wherein, if said sensing device (1 ) stops providing said data indicative of said movement, said determining said start time (ts), said end time (tE) and said peak time (tP) is stopped and said null-velocity instants (t*) subsequent to said end time of said preceding iteration are discarded.

The method according to claim 12 or 13 wherein, if said start time (ts), said end time (tE) and said peak time (tp) are not determined before a predetermined time gap has lapsed since said end time of said preceding iteration, said determining said start time (ts), said end time (tE) and said peak time (tp) is stopped and said null-velocity instants (t*) subsequent to said end time of said preceding iteration are discarded.

A system (100) for monitoring the movement of a part of a human body (2), said movement comprising a number N of iterations of a rotation in a plane (xy) of said part of said human body, said system (1 00) comprising:

a sensing device (1 ) suitable for cooperating with said part of said human body (2) and for providing data indicative of said movement of said part of said human body (2); and

a processing unit (3) configured to process said data so as to generate a rotation signal (0(t)) indicative of said rotation of said part of said human body (2) in said plane (xy) and to identify a portion of said rotation signal (0(t)) corresponding to a respective iteration of said rotation of said part of said human body (2) in said plane (xy) by determining a start time (ts), an end time (tE) and a peak time (tp) of said respective iteration, said determining comprising:

determining a plurality of null-velocity instants (t*) wherein an angular velocity of said part of a human body (2) in said plane (xy) is substantially null;

determining, amongst said plurality of null-velocity instants (t*), a set of candidate start/end times and a set of candidate peak times on the basis of at least one condition on relative values of said rotation signal (0(t)) in correspondence of said plurality of null-velocity instants (t*); and

determining said start time (ts), said end time (.E) and said peak time (tp) as a combination of two candidate start/end times and a candidate peak time that fulfils at least one condition on values of said rotation signal (0(t)) in correspondence of said candidate start/end times and said candidate peak times.

16. A computer program product loadable in the memory of at least one computer (3) and including software code portions for performing the steps of the method of any of claims 1 to 14, when the product is run on the at least one computer (3).