FALL DETECTION SYSTEM AND A METHOD OF OPERATING A FALL DETECTION SYSTEM

• US 20110201972A1
• Filed: 10/09/2009
• Published: 08/18/2011
• Est. Priority Date: 10/17/2008
• Status: Active Grant

• Current Assignee: Lifeline Systems Company (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Ten Kate, Warner Rudolph Theophile
• Granted Patent: US 9,754,470 B2
• Time in Patent Office: Days
• US Class Current: 600/595
• CPC Class Codes: G08B 21/0446 worn on the body to detect changes of posture, e.g. a fall, inclination, acceleration, gait

Abstract

An alarm (35) provided by a fall detection system (2) may be caused by an accidental drop of the system. Therefore prior to issuing the alarm the fall detection system a confirmation is needed that a potential fall originates from a fall detection system that is worn by a user (4). A fall of a fall detection system that is not attached to a user is characterized by the occurrence of one or more full rotations of the system. Said rotations are identified by analyzing the output signal of a magnetometer, and by detecting a periodicity in said output signal. The fall detection system (2) provides the alarm in dependence of an identified absence of at least one full rotation.

Claims

1. A fall detection system (2) comprising a magnetometer (20) for monitoring the movement of a user (4) of the fall detection system, the system (2) being arranged to provide an alarm (35) in dependence of an identified fall, the system (2) being characterized in further comprising analyzing means (30) coupled to the magnetometer (20) and arranged for analyzing an output signal (25) of the magnetometer to identify an absence or presence of at least one full rotation of the system (2), the rotation being at least over 360 degrees, the system being further arranged to provide data on the identified absence or presence of at least one full rotation.

2. A fall detection system (2) according to claim 1 wherein the system is further arranged to provide said alarm further in dependence of the identified absence or presence of at least one full rotation.

3. A fall detection system (2) according to claim 1 wherein the analyzing means (30) being further arranged to analyze the output signal (25) and to identify the absence or presence of at least one full rotation in response to an identified fall.

4. A fall detection system (2) according to claim 1 wherein said system (2) further comprises an accelerometer (50) coupled to the analyzing means (30) and arranged to provide a signal (55) indicative of an acceleration of the system (2), the analyzing means (30) being further arranged to analyze the signal (55) and to identify the absence or presence of at least one full rotation in response to the signal (55) of the accelerometer (50) having exceeded a predetermined threshold value.

5. A fall detection system (2) according to claim 1 wherein the analyzing means (30) are arranged to determine a periodicity of the output signal (25).

6. A fall detection system (2) according to claim 5 wherein the analyzing means (30) are arranged to determine the periodicity using an autocorrelation function performed on the output signal (25) of the magnetometer.

7. A fall detection system (2) according to claim 5 wherein the analyzing means (30) comprise:

an analog to digital converter (75) coupled to the magnetometer (20) arranged to convert the output signal (25) to a plurality of digital codes,

a memory (80) coupled to the analog to digital converter (75) and arranged for storing said plurality of digital codes,

a processor (90) coupled to said memory and arranged for retrieving said digital codes from said memory and further arranged for determining the periodicity of said output signal (25) in dependence of said plurality of digital codes.

8. A method of operating a fall detection system, the method comprising a first step (100) of analyzing one or more sensor signals to identify a potential fall by a user of the fall detection system and a second step (110) of providing an alarm in response thereto, the method being characterized in comprising a third step (120) of analyzing an output signal provided by a magnetometer to detect the absence or presence of at least one full rotation of the fall detection system comprising the magnetometer, wherein the rotation is at least over 360 degrees, the system further providing data on the identified absence or presence of at least one full rotation.

9. A method according to claim 8 wherein the second step (110) of providing an alarm is further in dependence of a determined absence or presence of at least one full rotation.

10. A method according to claim 8 wherein the third step (120) is performed in response to a detected potential fall by the first step (100).

11. A method according to claim 8 wherein the step (100) of analyzing to detect the absence or presence of at least one rotation comprises determining a periodicity of said output signal.

12. A method according to claim 11 wherein the periodicity of the output signal is determined using autocorrelation performed on the output signal of the magnetometer.

13. A method according to claim 8 wherein the first step comprises analyzing an acceleration signal provided by an accelerometer comprised in the fall detection system.

14. Use of a determined periodicity in the output signal (25) of a magnetometer (20) comprised in a fall detection system (2) to determine the absence or presence of least one full rotation of the system, wherein the rotation is at least over 360 degrees, said fall detection system providing data on the determined absence or presence of at least one full rotation.

15. Use according to claim 14 wherein the fall detection system provides an alarm (35) in response to a detected fall and the determined absence or presence of at least one full rotation.

16. A computer program product for use in a fall detection system (2), the computer program product comprising program code that, when executed on a processor (90), is adapted to detect a fall by a user of the fall detection system, analyze an output signal (25) provided by a magnetometer (20) to detect the absence or presence of at least one full rotation of the fall detection system comprising the magnetometer, wherein the rotation is at least over 360 degrees.

17. A computer program product according to claim 16 further comprising program code that, when executed on a processor (90), is adapted to provide an alarm (35) in dependence of a detected fall and a determined absence or presence of at least one full rotation.