Wearable obstacle-detection device, and corresponding method and computer program product

Patent metadata

Field	Value
Publication number	US-9846231-B2
Application number	US-201514788029-A
Country	US
Kind code	B2
Filing date	Jun 30, 2015
Priority date	Jul 25, 2014
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A device for detecting obstacles that is wearable by a subject, for example integrated in an item of footwear. The device includes an ultrasound source for emitting an ultrasound transmission signal and an ultrasound receiver for receiving a corresponding ultrasound signal reflected by an obstacle, a control module for measuring a time of flight between emission of the ultrasound transmission signal and reception of the corresponding ultrasound signal reflected by the obstacle and calculating, on the basis of the aforesaid time of flight, the distance at which the obstacle is located. The device comprises an inertial sensor, in particular an acceleration sensor, designed to measure acceleration of the foot along three axes, and a control module configured for enabling operation of the ultrasound source if the aforesaid acceleration values measured by the inertial sensor respect a given condition for enabling measurement of the time of flight.

First claim

The invention claimed is:

1. A device for detecting obstacles that is wearable by a subject, said device comprising:
an ultrasound source configured to emit an ultrasound transmission signal;
an ultrasound receiver configured to receive a corresponding ultrasound reflected signal reflected by an obstacle;
a control module configured to measure a time of flight between emission of the ultrasound transmission signal by the ultrasound source and reception of the reflected ultrasound signal by the ultrasound receiver and calculate, based on said time of flight, a distance at which said obstacle is located; and
an acceleration sensor configured to measure acceleration values of the subject along three axes, respectively; and
wherein the control module is configured to enable operation of the ultrasound source and enable measurement of the time of flight in response to determining that said acceleration values measured by said acceleration sensor indicate that a foot of the subject is resting on a resting surface during a walk.

2. The device according to claim 1 , wherein the control module is configured to enable operation of the ultrasound source and enable measurement of the time of flight in response to determining that a longitudinal acceleration and/or a lateral acceleration are zero or constant and a vertical acceleration is equal to the acceleration of gravity.

3. The device according to claim 1 , wherein the control module includes components that define a measurement chain configured to measure the time of flight between emission of the ultrasound transmission signal and reception of the ultrasound reflected signal and calculate, based on said time of flight, the distance at which said obstacle is located, said measurement chain including a time-gain-compensation section.

4. The device according to claim 3 , wherein said time-gain-compensation section includes a comparator configured to compare an amplitude of the ultrasound reflected signal with a reference signal.

5. The device according to claim 4 , wherein said reference signal decreases over time, following upon each enabling of measurement by the control module, according to a decreasing exponential, as a function of a propagation attenuation of a medium in which the ultrasound waves of the ultrasound transmission signal propagate.

6. The device according to claim 1 , wherein said acceleration sensor is configured to verify that said acceleration values measured by said acceleration sensor indicate that the foot of the subject is resting on the resting surface during the walk and send an interrupt signal, indicating that the foot is resting on the resting surface, to a microcontroller implementing said control module, said microcontroller being configured to enable operation of the ultrasound source upon reception of said interrupt signal.

7. The device according to claim 1 , further comprising an alarm indicator configured to generate an alarm signal when said distance of the obstacle detected falls within a given range of distances.

8. The device according to claim 7 , wherein said alarm indicator is configured to vary said alarm signal as a function of the distance from the obstacle.

9. The device according to claim 1 , wherein the ultrasound source, ultrasound receiver, control module, acceleration sensor, and control module are integrated in an item of footwear and said acceleration sensor is integrated in a sole of said item of footwear.

10. A method, comprising:
detecting an obstacle via a device for detecting obstacles that is wearable by a subject, the detecting including:
emitting ultrasounds from an ultrasound source and receiving ultrasounds reflected from the obstacle,
measuring a time of flight between said emitting and said receiving,
calculating, based on said time of flight, a distance at which said obstacle is located,
measuring acceleration values of the subject along three axes, and
enabling operation of the ultrasound source in response to determining that said measured acceleration values indicate that a foot of the subject is resting on a resting surface during a walk.

11. The method according to claim 10 , comprising generating an alarm signal in response to determining that said distance detected falls within a given range of distances.

12. A non-transitory computer readable medium including program code that, when run on at least one computer, implement a method comprising:
detecting an obstacle via a device for detecting obstacles that is wearable by a subject, the detecting including:
measuring a time of flight between an ultrasound source of said the device emitting ultrasounds and receiving ultrasounds reflected from the obstacle,
calculating, based on said time of flight, a distance at which said obstacle is located,
measuring acceleration values of the subject along three axes, and
enabling operation of the ultrasound source in response to detecting that said measured acceleration values indicate that a foot of the subject is resting on a resting surface during a walk.

13. The non-transitory computer readable medium according to claim 12 , wherein the method includes causing an alarm indicator to generate an alarm signal in response to determining that said distance detected falls within a given range of distances.

14. The non-transitory computer readable medium according to claim 13 , wherein said alarm indicator varies said alarm signal as a function of the distance from the obstacle.

15. The non-transitory computer readable medium according to claim 12 , wherein detecting that said measured acceleration values indicate that the foot of the subject is resting on the resting surface includes determining that a longitudinal acceleration and/or a lateral acceleration are zero or constant and that a vertical acceleration that is equal to the acceleration of gravity.

16. The non-transitory computer readable medium according to claim 12 , wherein detecting that said measured acceleration values indicate that the foot of the subject is resting on the resting surface is performed by an inertial sensor that sends an interrupt signal, indicating that the foot of the subject is resting on the resting surface, to a microcontroller that enables operation of the ultrasound source upon reception of said interrupt signal.

17. The method according to claim 11 , wherein said alarm indicator varies said alarm signal as a function of the distance from the obstacle.

18. The method according to claim 10 , wherein detecting that said measured acceleration values indicate that the foot of the subject is resting on the resting surface includes determining that a longitudinal acceleration and/or a lateral acceleration are zero or constant and that a vertical acceleration that is equal to the acceleration of gravity.

19. The method according to claim 10 , wherein detecting that said measured acceleration values indicate that the foot of the subject is resting on the resting surface is performed by an inertial sensor that send an interrupt signal, indicating that the foot of the subject is resting on the resting surface, to a microcontroller that enables operation of the ultrasound source upon reception of said interrupt signal.

Assignees

• St Microelectronics Srl

Inventors

• D'Angelo Francesco
• Corona Stefano

Classifications

• G01S7/529

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