Captured Image corruption, possible buffer Problem

[georgebastille]

Hi, I am using LabVIEW 8.2 and Vision 8.2.0. I am using a Pixelink Firewire camera and the NI IMAQ-dx IIDC driver. I can initialise the camera in NI-MAX and it operates perfectly. I can run Grab.vi and the camera works well. However, when I run two loops in parallel, the captured image is corrupted. Specifically, if I capture a 1024 by 768 image, it shows a green line horizontally across the centre and the lower half is then split further by a vertical green line. The behaviour can be reproduced by opening Grab.vi (from the NI examples), and adding a separate while loop which displays the current loop counter (i) on the front panel. I think it could be a buffering problem, the first half of the image comes from one buffer and the second half from the next, but even that does not explain the behaviour, as it appears that the lower half of the aquired image is split in half and the two half keep swapping, back and forth.

If I the go into MAX and grab some images, the same thing happens. If I then change the resolution from within MAX and re grab images, it is fixed. As soon as I then run the labview program again, the problem comes back, and stays until I change something in MAX again.

Thanks in advance for your help

[Elmar_NI]

Hello Georgeba,

its sound a littel bit confusing. You use two parallel loop to acquire an image of one cam or i didn´t catch the sentence.
Maybe you could send me your lv code and the typ of cam which you are using.
If its work in Max it should also work in labview.
Improtant is that you set the parameters in Max test it out with grap or snap.
And SAVE it in the upper toolbar.
After that switch to labview and try an Imaqdx example. Under Hardware Input output.
It should work correctly if the image was correct in MAX.

Kind regards,

Elmar