Low rate and termination of frame grabbing using IMAQ image acquisition

[Mahdi_Es]

Hi,

I have a fast camera which is connected to desktop computer through PCIe-1433 NI card. I have written a LabVIEW code to save all the frames of camera. Attached is the snapshot of the code.

 

There are two weird problems happening when I run the code.

(1) The number of "read frames" and "acquired frames" are different from each other’s. In other words, if camera take 100K images per second, I just can see and save 1K of these images.

(2) The stranger problem is that after some point, for example 5 seconds, the rate of reading frames stops and does not change, as if the program does not work.

 

I really appreciate if anyone can help me figuring out the problem.

Thanks

[Antoine Chalons]

I don't have Vision Dev module anymore so I can't send you code, sorry.

There are a few things to consider, here, what is your camera (brand, model)? And do you have a fast drive to save on (SSD)?

I'm asking this because most probably, the code you wrote is limited by the fact acquisition and saving are done in the same loop.

And I doubt that - even with an SSD - your computer would be able to acq+save 100k images per second, even if those images are small in resolution.

Also note that saving to TIFF might not be the fastest option.

I think you have to go for a slightly more elaborated architecture and use 2 loops, one for acquisition and another one for saving.

About 10 years ago I made a system that was acquiring 4k images per second (tiny images, 128*1000 8bit monochrome), it had to work without an SSD not we were limited in the duration of acquisition depending on the RAM, the concept was to fill the RAM for as long as we could, stop the acquisition and save to disk.

But the first step for you I guess is to calculate the throughput in Mbytes /s that you'd like to achieve, I'd say 200 Mbytes or lower you culd probably stream to disk untill it's full.

[Antoine Chalons]

Also, I think you can find advanced examples if you go to Help > Find examples > vision

[Rolf Kalbermatter]

If that 100k image per second is not a typo, you are definitely not just pushing the limits of what modern PC hardware can do, but in fact operating in lala land. Even super high speed cameras don't get that high.

[ensegre]

34 minutes ago, Rolf Kalbermatter said:

If that 100k image per second is not a typo, you are definitely not just pushing the limits of what modern PC hardware can do, but in fact operating in lala land. Even super high speed cameras don't get that high.

well, some do...

Anyway, many years ago I had too a project with 1.25Mp@500fps. Needed a raid array of 8 hard disks to stream seamlessly, raw bytes only, of course.

Edited August 24, 2022 by ensegre