NI Vision - Copy overlay issue

[drodrig]

Hello,

I would like to know why exactly this does not work:

What I want is to keep the overlays on the picture. But it removes the past overlay every loop. How can I use Copy Overlay correctly?

Thanks,

David

[wiebe@CARYA · Accepted solution]

You could start by adding output errors indicators to the VI's. I haven't tried, but there might be meaningful error messages.

I'd suspect that the last VI needs two different images. You are wiring the same image. Note that those images are some sort of pointer. So the output of the VI is really the same pointer to the same image. You probably need to provide a second image that can store the result. Then you need to switch the destination image so it's the source in the next iteration (and vice versa).

Also, the feedback node will not have a valid image on the first iteration. You need to wire a valid image to the init of the FBN. But as I hopefully made clear, the FBN doesn't do much at the moment.

[drodrig]

There were no errors, but you are right about the different images. Finally, I used an auxiliary image to draw the overlays. At the end of each iteration the overlays of the auxiliary image are copied to the acquisition image. I don't know if this is the most efficient way, but it worked.

Thanks for the assistance!

[wiebe@CARYA]

And +1 for posting the solution!