Image aquisition with high speed camera

For my application, I want to use the image aquisition toolbox (with the NI Frame Grabber Support) to save images of fast moving objects taken by a high speed camera. These should be processed (recognition of object size and position using regionprops command)

The camara is recording with ~ 1000 fps, recording time min. 10 min.

The approaches I thought on:

Plan 1: Use shapshot function (https://de.mathworks.com/help/imaq/examples/acquiring-a-single-image-in-a-loop.html) in a loop, process image and only store required information (output from regionprops) in a cell.

Problem 1.1: Camera will be faster than loop and I need the high frame rate. Any ideas how to still get all informations?

Plan 2: Use imaqtool to create and save video, read in video later.

Problem 2.1: How to stop aquisition if video is "full"? (e.g: Maximal file size and size per frame- how do I get this? Or is there an automated possiblity?)

Problem 2.2: How can I set the framerate constant? (I need the object velocity so time interval between frames is important- when testing the image aquisition toolbox with my normal webcam, I had set the framerate to 30 but the shown framerate in the toolbox was 30 - 40. I need the framerate to be constant or at least the time stamp for each frame to calculate the error)

Thanks for your help! :)

Answer 1

[Walter Roberson]

The approaches you describe cannot work.

You need a hardware trigger for constant frame rate. However if you were using an ni CompaqDaq chassis you might be able to use software control to tell the chassis what trigger rate to set.

You need a big frame buffer attached to the frame grabber.

In theory you could use a standalone device with SSD and hardware trigger to record everything for later transfer.

I would not even try to do this without using an interface that was one of USB 3, or Thunderbolt 3, or Gigabit Ethernet, or pci express (in which case you should consider Thunderbolt 3)

Perhaps it might be feasible with a GigE camera; I would have to know more about the image sizes (and do a bunch of research)

Any attempt to use software triggers such as snapshot will have too much jitter, too much latency.

(At 1000 fps I wonder whether you are going to have sufficient brightness for imaging.)

[Nora Ruprecht]

Thanks for your answer!

By hardware trigger you mean e.g. as shown here?

https://de.mathworks.com/help/daq/ref/addtriggerconnection.html

And by frame buffer something like this? (or am I on the wrong track?- just getting started with image aquisition)

https://de.mathworks.com/help/signal/ref/buffer.html

The brigtness is not a problem- I will get the camera but unfortunately no software installed to it.

[Walter Roberson]

Is the camera an SC2X from Edgetronic ? https://edgertronic.com/our-cameras/sc2x at about $US16000 each? Is it one of the devices from https://www.krontech.ca ? The first generation device from them cannot record for the time length you need and the second generation is not available as yet. Is it a Sony RX100 VA ?

[Nora Ruprecht]

It is CP70-16-M/C-148 from Optronis

[Walter Roberson]

National Instruments does not appear to make any frame grabbers that work with that device, as it uses Coaxpress interface.