VBAI decrease of the frame rate

[ExpertiseVision_UM]

Concern/tested with: VBAI 2009 SP1, 2010 + Smart camera 1742, 1744 

When I display the picture in a custom interface, I have a decrease of the frame rate.

Where does it comes from? 

How can I solve this problem?

Work around: Do not display any image in the custom user interface, but rather download pictures using the "image logging" tool *without* option "log as background Task"

thanks for your help. 

[chat-relotte]

Hello,

I have a few questions about your setup. How do you see this decrease of the frame rate? How do you measure it ? Do you have a GigE network card that you can directly connect to the smart camera? Can you send me an example?

Best regards,

[ExpertiseVision_UM]

Cheers

Well, this is not exactly a frame rate decrease, but rather the fact that we miss images.
Here is an explanation:

We have set up two applications, using smart cameras, to gauge screw parts.
Those parts have side holes, which presence (and scraps in it) has to be checked.
To do so, parts are turned between camera and backlight, and images are acquired continuously. A simple (and fast) "intensity" tool is used to detect for light in the hole.
After 180° (given by the number of acquired images. Images are triggered by an encoder), we compare the maximum value of intensity with a lower tolerance.
The rotation speed is constant and designed to always see part of the hole.

When we display the last image within VBAI interface, we mostly "miss" the hole and we get a number of "missed images" from the "Acquire Image" tool output.
Please note that we do not try to output images during the rotation.
Another clue: the problem doesn't occur on the very first part after the inspection has loaded.

Hope this help.

[BruceAmmons]

I know in LabVIEW that once you display an image, it keeps updating from the source image.  Perhaps after you display the image VBAI automatically refreshes the image during acquistion, slowing down the process.

Here's the annoying obvious suggestion:  Don't display an image after the inspection.  If that solves your problem, you are done.

Perhaps if you copy the image and display the copy, it would stop refreshing during acquisition.

Bruce

[Brad]

The Custom UI step is already making a copy behind the scenes to avoid the problem Bruce mentioned (i.e. for every image display control on the custom UI, we have a dedicated image allocated behind the scenes that we copy into when the step needs to update the image display). This copy may take time if the image is large though, and this could explain why you miss images. If you're timing is that tight, you can either do what Bruce suggested and not update the UI, or see if you can optimize the inspection to give you more time to allow for the copy. I could take a look at your inspection if you want to post it and see if there any areas for improving efficiency (or you can send it to vbai.support@gmail.com if you don't want to put it on a public forum).

Thanks,

Brad