Persistent image collection (how to obtain the maximum value of each pixel in a series of IMAQ frames) for background subtraction

[mk@opc]

Hello all,

    I have a LabVIEW system which takes advantage of the IMAQ tools and Vision Development Module features.  A useful feature that I have implemented is being able to take a snapshot of the video stream, and then subtract that single frame from the subsequent images.

    What I would like to do is collect a series of images instead of just one, and then create a single image from those frames that is just the maximum pixel value in each pixel location (kind of like a persistent display).

    This would probably be very easy to implement by converting the image to an array and then doing number math on the array and then converting back into an image, but I am hoping someone here may know of a way to use the IMAQ/VDM tools to do this in a more compact way.

Thank you very much,

MK

[udka · Accepted solution]

How about using IMAQ compare Max operation ?

[mk@opc]

Thank you!

My new question is what is the operator enum supposed to be for "max"?   How do I find this information, it's not in the spec -- http://zone.ni.com/reference/en-XX/help/370281U-01/imaqvision/imaq_compare/

[udka · Accepted solution]

If you create a constant/control for operator terminal, you can get the enum and you can select max.

[mk@opc]

thanks uday!! works exactly as I wanted 🙂 cheers