Grabbing images at 60 hz with IMAQ grabber and showing them

[Biebel]

Hi all,

I'm programming an application where I 've to show and do some realtime (60hz) calculations on a thermal image coming from a thermal camera through GigE

At the beginning, the program works fast, good framerates, but after a while, framerates start dropping, and eventually will stop.

When I remove the Imaq image viewer (right, I do not work with the external windraw), the program doesn't slow down, but than I haven't any image anymore;)

I tried with synchronous displays etc, but nothing helps.

Any idea's? 

in annex, you have a screenshot of a part of the program.

Thanks

[TiTou]

What's more important in you application? Doing the calculations on all the images at 60Hz or display the images at 60Hz? (not sure you monitor goes that fast and not sure your eye can make the difference anyway...)

IMAQ Windraw is not that hard to use and (at least in the past) it was much faster than image display control, I still use IMAQ Windraw when I know I want to go fast.

Maybe you could refresh the image diplay at a different rate by puting just the indicator in a case structure and use the "i" to only display every other image, thus display at 30Hz but do the calculations at 60Hz.

[ThiCop]

Hello Biebel,

Can you share your actual VI's/code (including subVI's)?

It would be interesting to see what you're doing in parallel in your timed loop.

Are you perhaps building any arrays in parallel or in other parts of your VI?

Is the memory and/or CPU usage of the program increasing with time?

Are there any other programs running in parallel?

What do you exactly mean with "after a while"?

Is this 5 seconds or rather several minutes or hours?

Decreasing the update rate could be a good idea, but in this case I think it could still cause issues.

Especially if your frame rate gradually drops, this could indicate a memory leak.

[ThiCop]

Hello,

I haven't heard back from you.

Were you able to resolve the issue?

[Biebel]

Hi,

Sorry for not answering.
I created another topic but actually, the question I asked there is the root cause for slowing down the program eventually.

So the solution is found in this topic: http://forums.ni.com/t5/LabVIEW/IMAQ-light-meter/td-p/2095700

I was using the light meter, which has an enable/disable input for drawing RIO's on the screen.
If you enable this, memory will increase slowly if you do not clear the screen every time.

Regards,

Bruno Sas 

[ThiCop]

Hello Bruno,

Thanks for the feedback!