remove the background noise in labview(limiting the size of 2d array)

[suzumiyalove]

hi

 　I am trying to remove the background noise in a camera image.I am measuring laser beam with a camera and labview. And I need to remove the background image so I can make further process on the beam image.

    I've tried storing the frame right before the trigger temporally and make the image with beam minus the one without(stored before). but it takes too much memory as I don't know how to limit the size of a 2D array.

   I'm new here and know little.

 any suggestion would be very much appreciated!!!

thanks! 

sl

[Bob_Schor]

Hmm -- I remember answering this post this morning, but I must not have pushed the "POST" button.

LabVIEW Vision is one of the more difficult parts of LabVIEW, partly because of the different way that the Image data is acquired, manipulated, and stored, partly because there are not so many examples and tutorials.  It certainly benefits from some LabVIEW experience, such as the ability to pass the CLAD exam.

When posting a "How do I?" question on the Forum, it is vital that you post the VI (or VIs) that you are trying to write and run.  Even if English (or French, or Japanese) is not your first language, LabVIEW Code is fairly "universal" (a While or For loop, a Queue, an Array function looks the same in all languages).  Please attach your VI -- if you have several of them, compress the folder that contains them all and attach the .zip file.

I don't understand your concern about "how to limit the size of a 2D array".  Most images are no bigger than 1000x1000 pixels, which takes 4MB if in color, a trivial amount of memory for a modern PC.  Again, without seeing the code, I don't know how to respond.

Bob Schor

[p4keal]

Please explain more exactly what You want to do. If You just want to subtract a background image You dont need to convert in arrays. Use IMAQ Create.vi to reserve space for your BG Image, save one and use IMAQ Subtract.vi. Sometimes it is enough to apply a threshold to you image, but again it depends of your goals.

As Bob_Schor said, LabVIEW Vision differs from "normal" LabVIEW programming. May be You need to create also memory space for result of subtraction.