PDA

View Full Version : Measurements in LabView between two frame (DFG/1394)



gbugnard
January 7, 2008, 08:55:23
Hi

I am using a DFG/1394-1e with LabView 8.2.1 (and all the IMAQ drivers and DAQmx and traditional drivers) and the IC Imaging Control 3.0.

I want to grab images and synchronously measure a pressure (that means for each picture, the corresponding measurement is taken). I thought, I could make a three point measurement of the pressure and then average it for each picture, but unfortunately, it doesn't works because of the DFG. In LabView,the DFG takes about 40 ms to grab on frame (which I can understand, due to the 25Hz frame rate). Could it be possible to:
1. Grab a picture
2. Make three measurements in LabView with 10ms interval
3. Compute the average of the measurements
4. Next step...
Within 40 ms for each step? Would it be possible to store a frame in a buffer memory during the measurement and then grab it within a few ms?

I attached a small VI file, how I grab the frame in LabView.

Thanks for the help.

Stefan Geissler
January 7, 2008, 10:47:27
Hi,

Unfortunatelly I have no LabVIEW 8.2.1 installed.

I suggest to use the ImageAvailable event. This is called every time a new frame is delivered by IC Imaging Control. In the event handler function you would do your measurements. Please make sure that you do them within 40 ms or less. Then you can measure 3 times in a 40 ms interval (25Hz).

The attached VI shows how to use the ImageAvailable event in LabVIEW.

gbugnard
January 11, 2008, 16:40:41
Thanks for the hint and the example Stefan. I will try out this method.