STEP LENGTH ESTIMATION METHOD AND PORTABLE TERMINAL FOR THE SAME

• US 20080120062A1
• Filed: 10/31/2007
• Published: 05/22/2008
• Est. Priority Date: 10/31/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., Seoul National University Industry Foundation (Seoul National University)
• Original Assignee: Samsung Electronics Co. Ltd., Seoul National University Industry Foundation (Seoul National University)
• Inventors: PARK, Chan-Gook, OH, Ji-Heon, PARK, Kyong-Ha, LEE, Jae-Myeon, HONG, Hyun-Su, KIM, Jin-Won
• Granted Patent: US 8,280,678 B2
• Time in Patent Office: Days
• US Class Current: 702/160
• CPC Class Codes: G01C 22/006 Pedometers

Abstract

An apparatus and method for estimating a step length of a user are provided. The apparatus and method use a step length estimation algorithm, e.g. a step length estimation parameter coefficient, according to a movement state of a user, i.e. whether the movement state is a walking state or a running state. The movement state of the user is determined on the basis of an acceleration variance value of an acceleration signal output from an accelerometer. Accordingly, the apparatus and method prevent errors in step length determinations.

Claims

1. A portable terminal comprising:

an accelerometer for detecting and outputting an acceleration signal of at least one axis;

a step detection unit for determining an acceleration variance value loom the acceleration signal;

a movement state determination unit for determining whether the acceleration variance value is larger than a critical value; and

a step length estimation unit for estimating a step length of a user corresponding to the determination regarding the acceleration variance value.

2. A portable terminal according to claim 1, wherein the movement state determination unit determines a movement state of the user and further wherein the movement state determination unit determines that the movement state is a running state if the acceleration variance value is larger than the critical value, and determines that the movement state is a walking state if the acceleration variance value is smaller than the critical value.

3. A portable terminal according to claim 2, wherein the step length estimation unit estimates the step length of the user using a step length estimation algorithm corresponding to the movement state of the user.

4. A portable terminal according to claim 1, wherein the step detection unit squares the acceleration signal on at least one axis of the accelerometer, summates a resultant square value and performs a sliding window summation and a low-pass filtering on the summated value.

5. A portable terminal according to claim 2, wherein the step length estimation unit stores at least one step length estimation parameter coefficient corresponding to the movement state of the user.

6. A step length estimation method in a portable terminal, the method comprising:

acquiring an acceleration signal;

determining an acceleration variance value from the acceleration signal;

determining whether the acceleration variance value is larger than a critical value; and

using a step length estimation algorithm corresponding to the determination regarding the acceleration variance value.

7. A method according to claim 6, further comprising determining a movement state of a user, wherein the movement state is determined to be a running state if the acceleration variance value is larger than the critical value and the movement state is determined to be a walking state ii the acceleration variance value is smaller than the critical value.

8. A method according to claim 6, wherein the using of the step length estimation algorithm comprises estimating the step length of the user using a step length estimation algorithm corresponding to the movement state of the user.

9. A method according to claim 6, further comprising:

squaring the output signal on at least one axis of the accelerometer;

summating a resultant square value; and

performing a sliding window summation and a low-pass filtering on the summated value.

10. A method according to claim 7, further comprising storing at least one step length estimation parameter coefficient corresponding to the movement state of the user.

11. A portable device comprising:

a step detection unit for determining an acceleration variance value;

a movement state determination unit for determining whether the acceleration variance value is larger than a critical value; and

a step length estimation unit for estimating a step length of a user corresponding to the determination regarding the acceleration variance value.

12. A portable device according to claim 11, further comprising an accelerometer for detecting and outputting an acceleration signal of at least one axis, wherein the step detection unit determines the acceleration variance value from the acceleration signal.

13. A portable device according to claim 12, wherein the step detection unit squares the acceleration signal on at least one axis of the accelerometer, summates a resultant square value and performs a sliding window summation and a low-pass filtering on the summated value.

14. A portable device according to claim 11, wherein the movement state determination unit determines a movement state of the user and further wherein the movement state determination unit determines that the movement state is a running state if the acceleration variance value is larger than the critical value, and determines that the movement state is a walking state if the acceleration variance value is smaller than the critical value.

15. A portable device according to claim 14, wherein the step length estimation unit estimates the step length of the user using a step length estimation algorithm corresponding to the movement state of the user.

16. A portable device according to claim 14, wherein the step length estimation unit stores at least one step length estimation parameter coefficient corresponding to the movement state of the user.