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Detecting LED/LCD Change

asked 2017-05-18 08:13:23 -0600

MP27 gravatar image


I'm looking to start a project that detects an LED changing state or a symbol being displayed on an LCD.

The camera and target would be fixed once setup, think about a user setting up the camera to look at and LCD screen of a device or some flashing LEDs.

I understand this could be very difficult and so my thoughts so far are that everything would be fixed in place and then a reference image is taken. The user could then draw on the image their area of interest and this information would be used to determine a state change.

Given that the image and the area of interest will be known what would be the best algorithm to reliably detect a change of state?

Obviously this algorithm would need to be able to cope with changes in light levels and very slight movement of the target.


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LBerger gravatar imageLBerger ( 2017-05-18 08:32:10 -0600 )edit

Hi LBerger,

I can't see how background subtraction would be useful in this application, could you expand a little about how this would detect and LED change please?

MP27 gravatar imageMP27 ( 2017-05-31 06:01:30 -0600 )edit

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answered 2017-05-18 08:23:24 -0600

cherault gravatar image


Did you try the histogram algorithm ? May be this will respond to your question...

Best regards,

Christophe Herault

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Hi Christophe,

I am familiar with the histogram, however I am not sure how you are suggesting I use it in this application, are you saying I monitor the histogram of my area of interest every frame and if it changes significantly then the LED/LCD must have changed?


MP27 gravatar imageMP27 ( 2017-05-22 10:22:39 -0600 )edit

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Asked: 2017-05-18 08:13:23 -0600

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Last updated: May 18 '17