METHODS AND APPARATUS TO COUNT PERSONS IN A MONITORED ENVIRONMENT

• US 20130232514A1
• Filed: 04/01/2013
• Published: 09/05/2013
• Est. Priority Date: 08/08/2008
• Status: Active Grant

• Current Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Original Assignee: The Nielsen Company LLC (MOOD Media Corporation)
• Inventors: Luff, Robert
• Granted Patent: US 9,344,205 B2
• Time in Patent Office: Days
• US Class Current: 725/12
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 2207/30196 Human being; Person
• CPC Class Codes: G06T 2207/30232 Surveillance
• CPC Class Codes: G06T 7/254 involving subtraction of images
• CPC Class Codes: G06V 10/421 by analysing segments intersecting the pattern
• 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: H04H 60/33 Arrangements for monitoring the users' behaviour or opinions

Abstract

Methods and apparatus to count persons in a monitored environment are disclosed. An example apparatus to count the number of people in a monitored environment is described, which includes an image sensor to collect a plurality of pixels, a pseudorandom number generator to pseudorandomly select at least one of a row of the pixels or a column of the pixels, a reader to read first pixel data generated by first pixels of the image sensor at a first time, the first pixels located in at least one of the row of the pixels or the column of the pixels, a comparator to compare the first pixel data with second pixel data generated by the first pixels at a second time different than the first time to generate first change values, and a counter to generate a count of persons based on the first change values.

Claims

1. An apparatus to count a number of persons in a monitored environment, comprising:

an image sensor to collect a plurality of pixels;

a pseudorandom number generator to pseudorandomly select at least one of a row of the pixels or a column of the pixels;

a reader to read first pixel data generated by first pixels of the image sensor at a first time, the first pixels located in at least one of the row of the pixels or the column of the pixels;

a comparator to compare the first pixel data with second pixel data generated by the first pixels at a second time different than the first time to generate first change values; and

a counter to generate a count of persons based on the first change values.

2. An apparatus as defined in claim 1, further comprising a storage device to store the change values and the at least one of the selected row or the selected column.

3. An apparatus as defined in claim 2, wherein the storage device is to store a count of audience members.

4. An apparatus as defined in claim 1, wherein the counter is to map the change values to facilitate detection of motion indicative of a person.

5. An apparatus as defined in claim 4, wherein the counter comprises a map interpolator to obtain second change values based on the first change values.

6. An apparatus as defined in claim 5, wherein the map interpolator is to generate the second change values by interpolating the first change values.

7. An apparatus as defined in claim 1, wherein the counter comprises a blob discriminator to determine a blob based on the first change values.

8. An apparatus as defined in claim 7, wherein the blob discriminator is to determine whether the blob is indicative of a person.

9. An apparatus as defined in claim 7, wherein the counter further comprises a non-human filter to determine whether the blob does not represent a person.

10. An apparatus as defined in claim 1, wherein the counter comprises a high-motion filter to determine whether the first change values are indicative of a high-motion event.

11. An apparatus as defined in claim 1, wherein the first pixel data comprises a brightness value and a color value.

12. An apparatus as defined in claim 1, further comprising a count comparator to determine whether the count of persons is equal to a previous count of persons.

13. A method to count a number of persons in a monitored environment, comprising:

pseudorandomly selecting at least one of a row comprising a first set of pixels from a plurality of rows or a column comprising a second set of pixels from a plurality of columns at a first time;

collecting first information sensed by the at least one of the first set of pixels or the second set of pixels at the first time;

comparing the first information to second information sensed by the at least one of the first set of pixels or the second set of pixels at a second time different than the first time to generate first change values; and

determining whether the change values are indicative of a person being present in the monitored environment.

14. A method as defined in claim 13, further comprising:

pseudorandomly selecting at least one of a second row comprising a third set of pixels from the plurality of rows or a second column comprising a fourth set of pixels from the plurality of columns at a third time;

collecting third information sensed by the at least one of the third set of pixels or the fourth set of pixels at the second time; and

comparing the third information to fourth information sensed by the at least one of the first set of pixels or the second set of pixels to generate second change values.

15. A method as defined in claim 14, wherein determining whether the first change values are indicative of the person further comprises determining whether the first and second change values in combination are indicative of the person in the monitored environment.

16. A method as defined in claim 15, further comprising determining whether the second change values are indicative of a second person in the monitored environment.

17. A method as defined in claim 13, wherein pseudorandomly selecting the at least one of the row comprising the first set of pixels from the plurality of rows or the column comprising the second set of pixels from the plurality of columns comprises generating pseudorandom numbers corresponding to respective locations of the first or second sets of pixels.

18. A method as defined in claim 13, further comprising placing the first change values in a map.

19. A method as defined in claim 13, further comprising determining whether the first change values are indicative of a high-motion event.

20. A tangible computer readable storage medium comprising computer readable instructions which, when executed, cause a processor to at least:

pseudorandomly select at least one of a row comprising a first set of pixels from a plurality of rows or a column comprising a second set of pixels from a plurality of columns at a first time;

collect first information sensed by the at least one of the first set of pixels or the second set of pixels at the first time;

compare the first information to second information sensed by the at least one of the first set of pixels or the second set of pixels at a second time different than the first time to generate first change values; and

determine whether the change values are indicative of a person being present in the monitored environment.

21. A storage medium as defined in claim 20, wherein the instructions further cause the machine to:

pseudorandomly select at least one of a second row comprising a third set of pixels from the plurality of rows or a second column comprising a fourth set of pixels from the plurality of columns at a third time;

collect third information sensed by the at least one of the third set of pixels or the fourth set of pixels at the second time; and

compare the third information to fourth information sensed by the at least one of the first set of pixels or the second set of pixels to generate second change values.

22. A storage medium as defined in claim 21, wherein the instructions are to cause the machine to determine whether the first change values are indicative of the person by determining whether the first and second change values in combination are indicative of the person in the monitored environment.

23. A storage medium as defined in claim 20, wherein the instructions are to cause the machine to pseudorandomly select the at least one of the row comprising the first set of pixels from the plurality of rows or the column comprising the second set of pixels from the plurality of columns by generating pseudorandom numbers corresponding to respective locations of the first or second sets of pixels.

24. A storage medium as defined in claim 20, wherein the instructions are further to cause the machine to place the first change values in a map.

25. A storage medium as defined in claim 24, wherein the instructions are further to cause the machine to process the map to determine a count of persons present in the map.