View Full Version : Live view mode for two camera (LabView)

December 1, 2008, 11:10:47

we use the FireWire CCD Cameras under LabView four our vision applications and it’s working well but now we have a problem.

We have two DFK 21BF04 camera and I can’t set the live view mode (LiveStart method) at both camera in same time.
We need a fast polling of two camera but without live view mode the image capture time is at about 800ms (for two camera) it is too long for us.

How can I increase the capture speed or use the live mode simultaneously ?

The used components:
DFK 21BF04 cameras
IC LabView Extension 2.0
IC Imaging Control 3.0 ActiveX

Thanks for help in advance !
Attila Bodolai

Stefan Geissler
December 1, 2008, 13:34:20

You should use two IC Imaging Controls, one for each camera. You can start both cameras simultaneously.

December 1, 2008, 15:21:31
Hi Stefan,

I am working on a similar problem. We wish to acquire images and log intensities at set intervals from two DMK31AF03 cameras. I have written a simple program using two IC Imaging Controls. With only one camera in place the program works. However, with the second IC control present neither camera starts.

I am attaching the simple vi I am workign on. It is written using Labview 8.6, but it is saved for 8.0. The 001.dat and 002.dat are generated for each camera using the device setup example.

Can you please have a look at the vi. Perhaps you can post up a simple vi which will do the same thing.

Kind regards,

Stefan Geissler
December 1, 2008, 15:43:58
Hi Dave,

At least, one of both cameras should start. If you want to start the second camera, which is connected to the same FireWire board, then you must use lower frame rates for both cameras.

Also if simulatneous, continuous image processing is needed, then the ImageAvailable event of IC Imaging Control is a good choise to be used. It is a little bit tricky to implement using LabVIEW and unfortunatelly I am not a LabVIEW expert.

Stefan Geissler
December 1, 2008, 15:47:59

Now I had a look in your sample. You use the cameras triggered, thus you should use the ImageAvailable event.

I attach a sample VI to this code.

December 1, 2008, 16:04:02
Hi Stefan,

I have dropped the frame-rate and now both cameras are working. Thank you for your advice.

I am not actually using 'triggering' for my work - that icon was an artifact from some old code. However, I believe using the 'ImageAvailable' approach may be useful all the same.

However we do not have access to IMAQ/Vision software. Do you a have a copy of the 'ImageAvailable' software which does not use IMAQ VIs (specifically it asked for IMAQ Dispose when I attempted to load it).

Kind regards, and thanks,

Stefan Geissler
December 1, 2008, 16:39:37

Unfortunatelly I have no other ImageAvailable sample. But you may implement it on your own. As I above mentioned, I am no LabVIEW expert.

In the sample the ImageAvailble event code uses parts of the grab_picture / grab_imaq vi code.

December 1, 2008, 22:41:38
Hi Stefan,

I decreased the frame rate (from 30fps to 10fps) and now both camera are working well !

Thanks for your advice !

I had to make some modifications on the "IC_Grab_IMAQ.vi" because every executing the vi creates a new images and allocates a memory area.
So after a short time should be the memory problem of the system, slow running, or freezing. So my opinion is better to create an image before starting the cyclic grabbing.

Thanks, and Best Regards


Stefan Geissler
December 2, 2008, 08:20:45
Hi Attila,

Thank you for your sample VI.

December 2, 2008, 12:21:05

Thanks to both of you for the info an vi's,