Display device on/off detection methods and apparatus

1. A display activity detector comprising:

memory including computer readable instructions; and

a processor to execute the instructions to at least:

extract regions from respective ones of captured video frames, the regions corresponding to a depiction of a display of a monitored media device;

compute a metric that is to represent an amount a first one of the regions of a first one of the captured video frames differs from a corresponding second one of the regions of a second one of the captured video frames; and

compare the metric to a threshold to determine whether the monitored media device is ON or OFF.

2. The display activity detector of claim 1 , wherein the first one of the captured video frames and the second one of the captured video frames are successive video frames.

3. The display activity detector of claim 1 , wherein the second one of the regions is at a same respective location in the second one of the captured video frames as the first one of the regions is in the first one of the captured video frames.

4. The display activity detector of claim 1 , wherein the processor is to:

determine that the monitored media device is ON when the metric exceeds the threshold; and

determine that the monitored media device is OFF when the metric does not exceed the threshold.

5. The display activity detector of claim 1 , wherein the processor is to determine whether the monitored media device is ON or OFF based on comparison of the metric to the threshold and a color of at least one of the first one of the regions or the second of the regions.

6. The display activity detector of claim 5 , wherein the processor is to increase a confidence associated with a determination that the monitored media device is OFF when the color is a uniform dark color.

7. The display activity detector of claim 1 , further including:

a video sensor to obtain a video signal representative of an area including the monitored media device; and

a frame grabber to obtain the captured video frames from the video signal.

8. An article of manufacture comprising at least one computer readable storage device or storage disk including computer readable instructions that, when executed, cause a processor to at least:

extract regions from respective ones of captured video frames, the regions corresponding to a depiction of a display of a monitored media device;

compute a metric that is to represent an amount a first one of the regions of a first one of the captured video frames differs from a corresponding second one of the regions of a second one of the captured video frames; and

compare the metric to a threshold to determine whether the monitored media device is ON or OFF.

9. The article of manufacture of claim 8 , wherein the first one of the captured video frames and the second one of the captured video frames are successive video frames.

10. The article of manufacture of claim 8 , wherein the second one of the regions is at a same respective location in the second one of the captured video frames as the first one of the regions is in the first one of the captured video frames.

11. The article of manufacture of claim 8 , wherein the instructions, when executed, cause the processor to: determine that the monitored media device is ON when the metric exceeds the threshold; and determine that the monitored media device is OFF when the metric does not exceed the threshold.

12. The article of manufacture of claim 8 , wherein the instructions, when executed, cause the processor to determine whether the monitored media device is ON or OFF based on comparison of the metric to the threshold and a color of at least one of the first one of the regions or the second of the regions.

13. The article of manufacture of claim 12 , wherein the instructions, when executed, cause the processor to increase a confidence associated with a determination that the monitored media device is OFF when the color is a uniform dark color.

14. A method comprising:

extracting regions from respective ones of captured video frames, the regions corresponding to a depiction of a display of a monitored media device;

computing, by executing an instruction with at least one processor, a metric that is to represent an amount a first one of the regions of a first one of the captured video frames differs from a corresponding second one of the regions of a second one of the captured video frames; and

comparing, by executing an instruction with the at least one processor, the metric to a threshold to determine whether the monitored media device is ON or OFF.

15. The method of claim 14 , wherein the first one of the captured video frames and the second one of the captured video frames are successive video frames.

16. The method of claim 14 , wherein the second one of the regions is at a same respective location in the second one of the captured video frames as the first one of the regions is in the first one of the captured video frames.

17. The method of claim 14 , further including:

determining that the monitored media device is ON when the metric exceeds the threshold; and

determining that the monitored media device is OFF when the metric does not exceed the threshold.

18. The method of claim 14 , further including determining whether the monitored media device is ON or OFF based on comparison of the metric to the threshold and a color of at least one of the first one of the regions or the second of the regions.

19. The method of claim 18 , wherein the determining of whether the monitored media device is ON or OFF includes increasing a confidence associated with a determination that the monitored media device is OFF when the color is a uniform dark color.

20. The method of claim 14 , further including:

obtaining a video signal representative of an area including the monitored media device; and

obtaining the captured video frames from the video signal.