Method, device and system for calibrating positioning device

• US 8,694,275 B2
• Filed: 07/25/2012
• Issued: 04/08/2014
• Est. Priority Date: 01/16/2009
• Status: Expired due to Fees

• Current Assignee: NEC China Co Ltd (NEC Corporation)
• Original Assignee: NEC China Co Ltd (NEC Corporation)
• Inventors: Wang, Yongcai, Zhao, Junhui, Fukushima, Toshikazu
• Primary Examiner(s): Le, John H
• Application Number:
  US13/557,754
• Publication Number:
  US 20120290256A1
• Time in Patent Office: 622 Days
• Field of Search: 702/94, 702/95, 702/122, 702150-152, 702/158, 340/539.13, 342/27, 342/417, 342/450, 455/456.1
• US Class Current: 702/94
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence

Abstract

Embodiments of the present invention provide not only a technical solution for calibrating a positioning device but also a technical solution for characterizing an area of interest in a space. Specifically, there is provided a system, which may include: a tag capable of emitting ranging signals, placed at location points which are selected as space feature points in the space; a positioning device in the space, configured to obtain relative coordinates of the space feature points in relation to the positioning device based on the ranging signals from the tag; and a server, configured to determine location parameters of the positioning device in the space based on the relative coordinates, so as to calibrate the positioning device. The positioning device can be calibrated automatically, fast and accurately using the system.

Claims

1. A system comprising:

a tag capable of emitting ranging signals, placed at at least two area of interest (AOI) feature points which can characterize an area of interest in a space;

a positioning device in said space, configured to obtain location parameters of said AOI feature points based on the ranging signals from the tag; and

a server, configured to characterize said area of interest based on the location parameters of said AOI feature points,

wherein the server determines location parameters of the positioning device based on the obtained location parameters of said AOI feature points, and

wherein when said area of interest is of an irregular shape,

said positioning device is further configured to obtain location parameters of at least three AOI feature points on a boundary of the area of interest by means of the tag, so as to constitute a feature point sequence;

said server is further configured to fit said feature point sequence so as to characterize the area of interest.

2. The system according to claim 1, wherein said server is further configure to group said feature points sequence and fit said AOI feature points which are grouped into the same group.

3. The system according to claim 2, wherein said server is further configured to compare whether an absolute value of a slope difference of lines determined by the AOI feature points is less than a predetermined threshold, and to group said AOI feature points into the same group if the absolute value of the slope difference is less than the predetermined threshold.

4. A method for characterizing an area of interest in a space, comprising:

receiving location parameters of at least two area of interest (AOI) feature points which can characterize the area of interest, wherein said location parameters are obtained by a positioning device deployed in the space; and

characterizing said area of interest based on said location parameters and determining location parameters of the positioning device based on the received location parameters of said at least two AOI feature points,

wherein when said area of interest is of an irregular shape, the method comprises;

receiving location parameters of at least three AOI feature points on a boundary of the area of interest, said at least three AOI feature points constituting a feature point sequence; and

fitting said feature point sequence to characterize the area of interest.

5. The method according to claim 4, wherein said location parameters are absolute coordinates of said AOI feature points in the space or relative coordinates of said AOI feature points in relation to the positioning device.

6. The method according to claim 4, wherein when said area of interest is a circle, and said AOI feature points are a center of said circle and an arbitrary point on the circle edge.

7. The method according to claim 4, wherein when said area of interest is a polygon, said AOI feature points are vertexes of said polygon.

8. The method according to claim 4, wherein when said area of interest is an ellipse, said AOI feature points are a center point of said ellipse, a cross point of a long axis of said ellipse with a ellipse edge, and a cross point of a short axis of said ellipse with a ellipse edge.

9. The method according to claim 4, wherein the fitting of said feature point sequence comprises:

grouping said feature point sequence; and

fitting said AOI feature points that are grouped into the same group.

10. The method according to claim 9, wherein the grouping of said feature point sequence comprises:

comparing whether an absolute value of a slope difference of lines determined by AOI feature points is less than a predetermined threshold; and

grouping said AOI feature points into the same group if the absolute value of said slope difference is less than the predetermined threshold.

11. The method according to claim 4, wherein said fitting comprises a one-order line-fitting algorithm or a high-order curve-fitting algorithm.

12. A device for characterizing an area of interest in a space, comprising:

receiving means for receiving location parameters of at least two area of interest (AOI) feature points which can characterize said area of interest, wherein said location parameters are obtained by a positioning device deployed in a space; and

characterizing means for characterizing said area of interest based on said location parameters,

wherein the characterizing means determines location parameters of the positioning device based on the received location parameters of said at least two AOI feature points,

wherein when said area of interest is of an irregular shape,

said receiving means further receives location parameters of at least three AOI feature points on a boundary of the area of interest to constitute a feature point sequence;

said characterizing means further comprises means for fitting said feature point sequence to characterize the area of interest.

13. The device according to claim 12, wherein the means for fitting said feature point sequence comprises:

means for grouping said feature point sequence; and

means for fitting said AOI feature points that are grouped into the same group.

14. The device according to claim 13, wherein the means for grouping said feature point sequence comprises:

means for comparing whether an absolute value of a slope difference of lines determined by AOI feature points is less than a predetermined threshold; and

means for grouping said AOI feature points into the same group if the absolute value of said slope difference is less than the predetermined threshold.