METHOD FOR MEASURING MOVEMENTS OF A PERSON WEARING A PORTABLE DETECTOR

• US 20080214963A1
• Filed: 12/21/2007
• Published: 09/04/2008
• Est. Priority Date: 07/02/2003
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Caritu, Yanis, Guillemaud, Regis
• Granted Patent: US 10,231,628 B2
• Time in Patent Office: Days
• US Class Current: 600/595
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/02444 Details of sensor A61B5/02427 takes precedence
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/1123 Discriminating type of movement, e.g. walking or running A61B5/1116, A61B5/112 take precedence
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths

Abstract

A process for detecting activity of a person, in which movements of the person are measured by at least one sensor attached to the person, and respective components of the movements due to external activity and due to physiological activity are separated. The process obtains a signal of the sensor, filters the signal to derive a filtered signal, the filtering including partitioning the signal of the center into a low frequency component and high frequency component, and subtracts the filtered signal from the signal of the sensor. The filtering further variably extracts portions of the high frequency component according to a criterion of either a minimal level or a minimal instability of the signal of the sensor, and the filtered signal includes the low frequency component and the extracted portions of the high frequency components.

Claims

1. A process for detecting activity of a person, in which movements of the person are measured by at least one sensor attached to the person, and respective components of the movements due to external activity and due to physiological activity are separated, the process comprising:

obtaining a signal of the sensor;

filtering the signal to derive a filtered signal, the filtering comprising a partition of the signal of the sensor into a low frequency component and a high frequency component; and

subtracting the filtered signal from the signal of the sensor;

wherein;

the filtering further comprises a variable extraction of portions of the high frequency component according to a criterion of at least one of a level or an unstability of the signal of the sensor,

and the filtered signal comprises said low frequency component and the extracted portions of the high frequency components.

2. A process according to claim 1, wherein the extracted portions of the high frequency components are time portions of the signal of the sensor.

3. A process according to claim 2, wherein the extracted portions of the high frequency components are submitted to intensity weightings before being incorporated into the filtered signal.

4. A process according to claim 3, wherein the weightings depend either on a plurality of levels of the signal or a plurality of levels of the instability of the signal.

5. A process according to claim 4, wherein the filtered signal is expressed by α

·

S+(1−

α

)·

Flp (S), S is the signal of the sensor, Flp (S) is a lowpass filtering of the signal of the sensor, and α

is a variable weighting coefficient associated to at least one of the level of the signal of the sensor or the unstability of the signal of the sensor.

6. A process according to claim 1, wherein the criterion of a minimal instability of the signal of the sensor is estimated according to inversions of direction of movements between two instants separated by a determined duration.