IMAQ live image shows in all IMAQ windows?

[Alias user name here]

I am seeing the Live image from a 1394 camera in all the declared IMAQ display windows - even though programitically I am NOT updating those windows. This is causing problems with pattern matching etc.


Vision 7.0.2.561
IMAQ 1394: 1.5.2

What is the problem?

[BruceAmmons]

You are using the same image space for all your displays.  You probably only allocated a single image and reused it for different things.  If you want to keep an image for display, you can't make any changes to it after you display it.  You should allocate several images and make copies of any of the ones you want to keep for display.  Typically, you can use the old image as the source and the new image as the destination.

When I am processing in a loop, I typically allocate an image just for a display.  I do the processing on other images, including any overlays, etc.  I make a copy right before I display it.  This minimizes the flickering of the image as I make changes to it.

Bruce

[Alias user name here]

Bruce,

Thanks for the reply, I have allocated several different IMAQ memory locations - and am using the "Imaq Copy" function to transfer an image to another image reference.

What I am seeing is a bug - I'm pretty sure it related to IMAQ needing a front panel reference to retain the image, - I think this because I see the problem when working with a imaq reference from a cluster in a sub-vi/sub-vi level. If I do the same function on the top level diagram the 'image confusion' goes away.

If I stop the abort the code with the sub-vi front panel open  - the problem goes away - then I close all sub-vi's it comes back. I truly wish they do a serious rework of the IMAQ routines.

That said, IMAQ is in a transitional state as the new functions and old one overlap - why one cannot pass one IMAQ data wire to another in a name cluster to 'transfer' a copy of the image is odd - you can do this- but what does the 'IMAQ Copy' do that this does not?

[BruceAmmons]

I have been using IMAQ without any problems for a long time.  I don't think it is a bug, but a misunderstanding of how IMAQ images work.

An IMAQ image reference refers to a location in memory that stores the image.  You can make copies of the reference, but they all still refer to the same image.  If you make changes to this image after you display it, the changes may show in the display.  This can happen without any attempt to update the display.

IMAQ does not need a front panel reference to retain an image.

Bruce