METHODS AND APPARATUS TO COUNT PEOPLE APPEARING IN AN IMAGE

• US 20070086623A1
• Filed: 10/11/2006
• Published: 04/19/2007
• Est. Priority Date: 12/11/2002
• Status: Active Grant

• Current Assignee: Nielsen Company (US), LLC
• Original Assignee: Nielsen Company (US), LLC
• Inventors: Ramaswamy, Arun, Nelson, Daniel, Srinivasan, Venugopal
• Granted Patent: US 7,466,844 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06T 7/254 involving subtraction of images
• CPC Class Codes: G06V 20/53 Recognition of crowd images, e.g. recognition of crowd congestion
• CPC Class Codes: G06V 40/103 Static body considered as a whole, e.g. static pedestrian or occupant recognition
• CPC Class Codes: H04H 60/33 Arrangements for monitoring the users' behaviour or opinions

Abstract

Methods and apparatus to count people appearing in an image are disclosed. One disclosed method reduces objects appearing in a series of images to one or more blobs; for each individual image in a set of the images of the series of images, represents the one or more blobs in the individual image by one or more symbols in a histogram; and analyzes the symbols appearing in the histogram to count the people in the image.

Claims

1. A method of counting people appearing in a digital image comprising:

reducing objects appearing in a series of images to one or more blobs;

for each individual image in a set of the images of the series of images, representing the one or more blobs in the individual image by one or more symbols in a histogram; and

analyzing the symbols appearing in the histogram to count the people in the image.

2. A method as defined in claim 1 wherein reducing the objects appearing in the series of images to one or more blobs comprises creating the one or more blobs using a convex hull program.

3. A method as defined in claim 1 further comprising, if no symbols are added to a third symbol appearing in the histogram during a period in which a number of images are analyzed, removing the third symbol from the histogram.

4. A method as defined in claim 3 wherein analyzing the symbols appearing in the histogram to count the people in the digital image comprises, counting the symbols appearing in the histogram having a size greater than a threshold.

5. A method as defined in claim 1 wherein the series of images comprises a series of amalgamated images.

6. A method as defined in claim 5 wherein the series of amalgamated images are derived from a series of difference images, the series of difference images being derived from a sequence of original images including the digital image.

7. An apparatus to count people appearing in a digital image comprising:

a processor;

a memory storing computer readable instructions which, when executed, cause the processor to;

reduce objects appearing in a series of images to one or more blobs;

for each individual image in a set of the images of the series of images, represent the one or more blobs in the individual image by one or more symbols in a histogram; and

analyze the symbols appearing in the histogram to count the people in the image.

8. An apparatus as defined in claim 7 wherein the processor reduces the objects appearing in the series of images to one or more blobs by creating the one or more blobs using a convex hull program.

9. An apparatus as defined in claim 7 wherein, if no symbols are added to a third symbol appearing in the histogram during a period in which a number of images are analyzed, the processor removes the third symbol from the histogram.

10. An apparatus as defined in claim 9 wherein the processor analyzes the symbols appearing in the histogram to count the people in the digital image by counting the symbols appearing in the histogram having a size greater than a threshold.

11. An apparatus as defined in claim 7 wherein the series of images comprises a series of amalgamated images.

12. An apparatus as defined in claim 11 wherein the series of amalgamated images are derived from a series of difference images, the series of difference images being derived from a sequence of original images including the digital image.