Apparatus and method for detecting step in a personal navigator

• US 20070067094A1
• Filed: 09/18/2006
• Published: 03/22/2007
• Est. Priority Date: 09/16/2005
• 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: Lee, Jae-Myeon, Hong, Hyun-Su, Park, Kyong-Ha, Kim, Jin-Won, Park, Chan-Gook
• Granted Patent: US 7,640,134 B2
• Time in Patent Office: Days
• US Class Current: 701/200
• CPC Class Codes: G01C 22/006 Pedometers

Abstract

A step detecting apparatus and method in a personal navigator where acceleration signals in at least two directions are acquired from an accelerometer sensor, as a pedestrian moves. Variances of the acceleration signals are calculated and summed. The variance sum is compared with a threshold. If the variance sum is greater than the threshold, it is determined that a detected step is a walking step. If the variance sum is less than the threshold, it is determined that the detected step is a mark-time step.

Claims

1. A step detecting apparatus in a personal navigator, comprising:

an accelerometer sensor for outputting acceleration signals with respect to at least two directions; and

a step detector for calculating variances of acceleration signals in the at least two directions received from the accelerometer sensor, summing the variances, comparing the variance sum with a threshold, and determining whether a detected step is a mark-time step or a walking step according to the comparison.

2. The step detecting apparatus of claim 1, wherein two of the at least two directions are a forward direction and a downward direction from the pedestrian.

3. The step detecting apparatus of claim 1, wherein the step detector counts mark-time steps and walking steps according to the determination.

4. The step detecting apparatus of claim 1, wherein the accelerometer sensor is an at least two-axis accelerometer sensor.

5. The step detecting apparatus of claim 1, wherein the threshold is a value for distinguishing a mark-time step and a walking step.

6. The step detecting apparatus of claim 1, wherein the step detector eliminates noise from the acceleration signals by sliding window summing.

7. A step detecting method in a personal navigator, comprising the steps of:

acquiring acceleration signals in at least two directions from an accelerometer sensor;

calculating variances of the acceleration signals and summing the variances;

comparing the variance sum with a threshold;

determining that a detected step is a walking step if the variance sum is greater than the threshold; and

determining that the detected step is a mark-time step if the variance sum is less than the threshold.

8. The step detecting method of claim 7, wherein two of the at least two directions are a forward direction and a downward direction from the pedestrian.

9. The step detecting method of claim 7, further comprising counting mark-time steps and walking steps according to the determination.

10. The step detecting method of claim 7, wherein the threshold is a value for distinguishing a mark-time step and a walking step.

11. The step detecting method of claim 7, further comprising eliminating noise from the acceleration signals by sliding window summing.

12. A step detecting method in a personal navigator, comprising the steps of:

(a) setting a walking step count, a mark-time step, and a step detection count to initial values;

(b) acquiring acceleration signals in at least two directions from an accelerometer sensor, and determining whether a step is detected;

(c) increasing the step detection count by one, upon detection of a step, calculating variances of the acceleration signals, and summing the variances;

(d) increasing the walking step count by one if the variance sum is greater than the threshold and increasing the mark-time step count by one if the variance sum is less than the threshold; and

(e) counting walking steps, mark-time steps, and step detections by repeating steps (b)-(d).

13. The step detecting method of claim 12, wherein two of the at least two directions are a forward direction and a downward direction from the pedestrian.

14. The step detecting method of claim 12, wherein the threshold is a value for distinguishing a mark-time step and a walking step.