Badge identification system

• US 6,647,142 B1
• Filed: 07/31/2000
• Issued: 11/11/2003
• Est. Priority Date: 08/19/1999
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Beardsley, Paul
• Primary Examiner(s): Johns, Andrew W.
• Assistant Examiner(s): Alavi, Amir
• Application Number:
  US09/628,461
• Time in Patent Office: 1,198 Days
• Field of Search: 382/162, 382/164, 382/165, 382/103, 382/115, 382/116, 382/118, 382/173, 382/181, 382/190, 382/199, 382/209, 382/203, 382/286, 235/381, 235/382, 235/382.5, 235/454, 235/462.1, 235/462.02, 235/462.03, 235/462.13, 235/469, 235/470, 235/494, 386/46, 358/906, 705/43
• US Class Current: 382/165
• CPC Class Codes: G06K 19/06018 one-dimensional coding
• CPC Class Codes: G06K 2019/06225 using wavelength selection, e.g. colour code
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks
• CPC Class Codes: G07F 9/02 Devices for alarm or indication, e.g. when empty; Advertising arrangements in coin-freed apparatus alarms or warning devices indicating the interruption of flow to be metered G07F15/10

Abstract

A method dynamically identifies a badge in a sequence of images of a scene acquired by a camera. Each image in the sequence includes a plurality of pixels, and each pixel has a color and an intensity. Each image is scanned to detect a border pixel. Adjacent pixels to the border pixel are connected to determine a connected region of pixels. An inner boundary of the connected region is determined, and an ellipse is fitted to the inner boundary. The internal pixels inside the ellipse are distorted to a circular form, and a plurality of spokes are fitted to the distorted internal pixels to identify colored segments. Then, an unique identity is associated with each badge according to the colored segments.

Claims

1. A method for dynamically identifying a badge in a sequence of images of a scene acquired by a camera, each image in the sequence including a plurality of pixels, each pixel having a color and an intensity, comprising:

detecting a boundary of the badge;

fitting an ellipse to the boundary;

distorting pixels inside the ellipse to a circular form;

identifying colored segments from the distorted pixels; and

associating a unique identity with each badge according to the colored segments.

2. The method of claim 1 wherein the border pixel having a border color and an intensity greater than a first threshold, and the adjacent pixels having the border color and an intensity greater than a second threshold, where the first threshold is greater than the second threshold.

3. The method of claim 1 further comprising:

scanning the pixels of each image in a left-to-right and top-to-bottom order.

4. The method of claim 1 further comprising:

following pixels in the connected region in a forward and left direction to detect the inner boundary.

5. The method of claim 2 wherein each pixel of each image has a color value C_p=(R_p,G_p,B_p) and the border color is C_t=(R_t,G_t,B_t), and further comprising:

determine a unit three-vector c_p=C_p/mag(C_p), where mag(C_p) is a magnitude of C_p;

determining a unit three-vector c_t=C_t/mag(C_t) of the border color; and

determine if a dot product D=c_p·

c_t is greater than a threshold τ

to determine if a particular pixel has the border color.

6. The method of claim 1 wherein a plurality of cameras acquire concurrently a plurality of sequences of images of a plurality of scenes, and further comprising:

tracking the badge in the plurality of scenes.

7. The method of claim 6 further comprising:

providing feedback via an output depending on a location of the badge in the scene.

8. The method of claim 1 wherein the badge is attached to an individual.

9. The method of claim 1 wherein multiple badges are concurrently and dynamically identified in the scene.

10. The method of claim 1 further comprising:

maintaining a database of information associated with each unique identity; and

providing feedback via an output based on the associated information.

11. The method of claim 1 wherein the badge is attached to an object.

12. The method of claim 11 wherein the object is stationary.

13. The method of claim 11 wherein the object is moving.