EFFICIENT METHOD FOR TRACKING PEOPLE

• US 20120014562A1
• Filed: 03/21/2010
• Published: 01/19/2012
• Est. Priority Date: 04/05/2009
• Status: Active Grant

• Current Assignee: Rafael Advanced Defense Systems Limited (Government of Israel)
• Original Assignee: Rafael Advanced Defense Systems Limited (Government of Israel)
• Inventors: Berkovich, Erez, Shapira, Dror
• Granted Patent: US 8,855,363 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06V 20/52 Surveillance or monitoring of activities, e.g. for recognising suspicious objects recognising microscopic objects G06V20/69
• CPC Class Codes: G06V 40/161 Detection; Localisation; Normalisation

Abstract

In accordance with one embodiment, a method to track persons includes generating a first and second set of facial coefficient vectors by: (i) providing a first and second image containing a plurality of persons; (ii) locating faces of persons in each image; and (iii) generating a facial coefficient vector for each face by extracting from the images coefficients sufficient to locally identify each face, then tracking the persons within the images, the tracking including comparing the first set of facial coefficient vectors to the second set of facial coefficient vectors to determine for each person in the first image if there is a corresponding person in the second image. Optically the method includes using estimated locations in combination with the vector distance between facial coefficient vectors to track persons.

Claims

1. A method to track persons, comprising the steps of:

(a) generating a first set of facial coefficient vectors by;

(i) providing a first image containing a plurality of persons;

(ii) locating faces of persons in said first image; and

(iii) generating a facial coefficient vector for each said face by extracting from said first image coefficients sufficient to locally identify each said face,

(b) generating a second set of facial coefficient vectors by;

(i) providing a second image containing a plurality of persons;

(ii) locating faces of persons in said second image; and

(iii) generating a facial coefficient vector for each said face by extracting from said second image coefficients sufficient to locally identify each face, and

(c) tracking the persons within said images, said tracking including comparing said first set of facial coefficient vectors to said second set of facial coefficient vectors to determine for each person in said first image if there is a corresponding person in said second image.

2. The method of claim 1 further comprising:

(a) generating a third set of facial coefficient vectors by;

(i) providing a third image containing a plurality of persons;

(ii) locating persons in said third image;

(iii) locating faces of persons in said third image; and

(iv) generating a facial coefficient vector for each said face by extracting from said third image coefficients sufficient to locally identify each said face,

(b) determining estimated locations in said third image of each said person from the location of each said person for which a first facial coefficient vector was extracted with the location of each said person for which second facial coefficient vector was extracted;

(c) determining the vector distance between each said second facial coefficient vector and each said third facial coefficient vector; and

(d) tracking the persons within said images, said tracking including using said estimated locations in combination with said vector distance between facial coefficient vectors to determine for each face in said second image which is the corresponding face in said third image.

3. The method of claim 1 wherein the number of coefficients in said facial coefficient vectors are in the range of 5 to 200 coefficients.

4. The method of claim 1 wherein the size of said face in said image is used to derive the three-dimensional position of the corresponding person.

5. The method of claim 1 further comprising determining a location of static objects, wherein the location of said static objects is used to facilitate said tracking.

6. The method of claim 1 wherein said first image is from a first image capture device and said second image is from a second image capture device.

7. The method of claim 1 wherein, in a case in which a first facial coefficient template in said first image does not correspond to any facial coefficient template for a face in said second image, said first facial coefficient template is retained for use in said comparing while said tracking is repeated for subsequent images.

8. The method of claim 1 wherein the provided image derives from a plurality of images that have been processed to generate said provided image.

9. The method of claim 1 wherein the images are provided from a storage system.

10. The method of claim 2 wherein the location is a two-dimensional location.

11. The method of claim 2 wherein the location is a three-dimensional position.

12. The method of claim 2 wherein said tracking includes comparing the two-dimensional locations of the bodies of persons in said images.

13. The method of claim 2 wherein said tracking includes comparing the three-dimensional positions of the bodies of persons in said images.

14. The method of claim 2 wherein said tracking includes color matching of persons in said images.

15. The method of claim 2 wherein said tracking includes texture matching of persons in said images.

16. The method of claim 2 wherein said tracking includes any method of matching persons in said images.

17. A system to track persons, the system comprising:

(a) at least one image capture device providing a first image;

(b) at least one image capture device providing a second image; and

(c) a processing system including at least one processor, operationally connected to said image capture device, configured to;

(i) generate from said first image a first set of facial coefficient vectors;

(ii) generate from said second image a second set of facial coefficient vectors; and

(iii) track persons using said first set of facial coefficient vectors with said second set of facial coefficient vectors.

18. The system of claim 17, wherein said processing system is further configured to:

(a) generate a third set of facial coefficient vectors;

(b) determine estimated locations in said third image of each said person from the location of each said person for which a first facial coefficient vector was extracted with the location of each said person for which second facial coefficient vector was extracted;

(c) determine the vector distance between each said second facial coefficient vector and each said third facial coefficient vector; and

(d) track the persons within said images, said tracking including using said estimated locations in combination with said vector distance between facial coefficient vectors to determine for each face in said second image which is the corresponding face in said third image.

19. The system of claim 17 wherein the number of coefficients in said facial coefficient vectors are in the range of 5 to 200 coefficients.

20. The system of claim 17, wherein the size of a face in said image is used to derive the three-dimensional position of the corresponding person.

21. The system of claim 17, further comprising determining a location of static objects, wherein the location of said static objects is used to facilitate said tracking.

22. The system of claim 17, wherein said first image is from a first image capture device and said second image is from a second image capture device.

23. The system of claim 17, wherein in a case in which a first facial coefficient template in said first image does not correspond to any facial coefficient template for a face in said second image, said first facial coefficient template is retained for use in said comparing while said tracking is repeated for subsequent images.

24. The system of claim 17, wherein the provided image derives from a plurality of images that have been processed to generate said provided image.

25. The system of claim 17, wherein the images are provided from a storage system.

26. The system of claim 18, wherein the location is a two-dimensional location.

27. The system of claim 18, wherein the location is a three-dimensional position.

28. The system of claim 18, wherein said tracking includes comparing the two-dimensional locations of the bodies of persons in said images

29. The system of claim 18, wherein said tracking includes comparing the three-dimensional positions of the bodies of persons in said images

30. The system of claim 18, wherein said tracking includes color matching of persons in said images.

31. The system of claim 18, wherein said tracking includes texture matching of persons in said images.

32. The system of claim 18, wherein said tracking includes any method of matching persons in said images.