System and method for object tracking anti-jitter filtering

• US 9,081,076 B2
• Filed: 11/12/2012
• Issued: 07/14/2015
• Est. Priority Date: 11/12/2012
• Status: Active Grant

• Current Assignee: IsoLynx LLC
• Original Assignee: IsoLynx LLC
• Inventors: DeAngelis, Douglas J., Reilly, Gerard M., Sigel, Kirk M., Evansen, Edward G.
• Primary Examiner(s): Huynh, Phuong
• Application Number:
  US13/674,747
• Publication Number:
  US 20140132452A1
• Time in Patent Office: 974 Days
• Field of Search: 702/150
• US Class Current: 1/1
• CPC Class Codes: A63B 2024/0025 Tracking the path or location of one or more users, e.g. players of a game
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 5/0018 Transmission from mobile station to base station
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/0294 Trajectory determination or predictive filtering, e.g. target tracking or Kalman filtering

Abstract

Object tracking anti-jitter filtering systems and methods. A plurality of raw location points for a tracking tag attached to a tracked object is received. The raw location points are stored within a raw location points buffer. Raw location points within an averaging window are averaged to generate an averaged location point. The averaged location point is stored within an averaged location points buffer for use within the object tracking system.

Claims

1. Object tracking anti-jitter filtering method, comprising:

receiving, within an object tracking system, a plurality of raw location points for a tracking tag attached to a tracked object;

storing the plurality of raw location points within a raw location points buffer;

averaging the raw location points within an averaging window to generate a first averaged location point; and

storing the averaged location point within an averaged location points buffer for use within the object tracking system;

wherein a period of the averaging window is based upon most recent speed of the tracked object, and is between a minimum period and a maximum period.

2. The method of claim 1, wherein the averaging window is positioned over most recent stored raw location points of the raw location points buffer.

3. The method of claim 1, wherein, for each generated average location point, the period is increased by a low period adjust value if the latest speed is less than a predefined low speed threshold.

4. The method of claim 1, wherein, for each generated average location point, the period is decreased by a high period adjust value if the latest speed is greater than a predefined high speed threshold.

5. The method of claim 3, further comprising:

determining a desired points value based upon most recent speed, wherein the desired points value is between a minimum points value and a maximum points value; and

if the number of raw location points within the averaging window is less than the desired points value, increasing the period until the number of raw location points included within the averaging window is equal to the desired points value.

6. The method of claim 5, wherein, for each generated average location point, the desired points value is increased by a low points adjust value if the latest speed is less than a predefined low speed threshold.

7. The method of claim 5, wherein, for each generated average location point, the desired points value is decreased by a high points adjust value if the latest speed is greater than a predefined high speed threshold.

8. The method of claim 6, wherein a center of the averaging window is positioned on the raw location points buffer at a fixed delay from most recent raw location point.

9. The method of claim 8, further comprising:

if there are no raw location points within the averaging window and a latest speed of the tracked object is greater than a predefined high speed threshold;

generating a projected location point based upon a determined direction of movement of the tracked object and a determined projection speed of the tracked object, wherein the direction and the projection speed are determined from previous two averaged location points; and

storing the projected location point within the averaged location points buffer.

10. The method of claim 9, further comprising:

if there are no raw location points within the averaging window and a projection interval is greater than a maximum projection interval;

if the projection speed is greater than zero, reducing the projection speed for each subsequently generated projection point;

wherein the projection interval is a cumulative period of consecutively generated projection location points.

11. The method of claim 10, further comprising:

determining, from averaged location points determined for the tracking tag and for at least one additional tracking tag attached to the tracked object, an object location of the tracked object based upon positions of the tracking tags relative to one another and relative to the tracked object; and

if one of the averaged location points is missing, correcting the object location based upon an orientation of the tracked object and a distance between the tracking tag associated with the missing average location point and an average position of all tracking tags;

wherein the orientation is determined from at least one average location point from each of two different tracking tags.

12. The method of claim 11, further comprising:

determining a current acceleration of the tracked object based upon three most recently determined average location points; and

if one or more of the latest speed and the current acceleration are greater than maximum physical characteristics of the tracked object, correcting the most recent average location point based upon the maximum physical characteristics.

13. Object tracking anti-jitter filtering system, comprising:

at least one processor;

memory coupled with the processor for storing raw location points of a tracked object;

an averaging filter, comprising machine readable instructions stored within the memory and executed by the processor, for averaging a plurality of the raw location points within an averaging window to generate an averaged location point having reduced jitter when compared to raw location points of the tracked object; and

,

a speed based period controller, comprising machine readable instructions stored within the memory and executed by the processor, for incrementally increasing a period of the averaging window when a latest speed of the tracked object is less than a predefined low speed threshold, and for decreasing the period when the latest speed is greater than a predefined high speed threshold.

14. The system of claim 13, further comprising:

a speed based point controller, comprising machine readable instructions stored within the memory and executed by the processor, for incrementally increasing a desired points value that defines the number of raw location points to average when a latest speed of the tracked object is less than the low speed threshold and for incrementally decreasing the desired points value when the latest speed is greater than the high speed threshold.

15. The system of claim 14, further comprising:

a speed based projection filter, comprising machine readable instructions stored within the memory and executed by the processor, for generating the averaged location point based upon at least two previously generated average location points for the tracking tag using a projection technique when a latest speed of the tracked object is greater than a predefined high speed threshold and the averaging window contains not received raw location points.

16. The system of claim 15, wherein the projection technique comprises at least one projection technique chosen from the group consisting of:

weighted averaging, linear interpolation, piecewise interpolation, polynomial interpolation, and curve fitting.

17. The system of claim 16, further comprising:

a multi-tag correction filter, comprising machine readable instructions stored within the memory and executed by the processor, for correcting an object location, determined by averaging the location of a plurality of tracking tags attached to the tracked object, towards the location of one tracking tag for which averaged location points are missing.

18. The system of claim 17, further comprising:

a physical limit filter, comprising machine readable instructions stored within the memory and executed by the processor, for adjusting the averaged location point when one or both of a latest speed of the tracked object and an acceleration of the tracked object exceeds maximum physical characteristics of the tracked object;

wherein the averaged location point is set to a location, relative to a previous averaged location point, that is within the maximum physical characteristics.