Camera attributes do not show (sometimes)

[Pindakaas]

I am aiming to configure a webcam (Trus Exis) so that the camera attributes can be configured in labview. This followed in a program (see attatched), however it sometimes does not work (camera attributes return empty and cannot be written). I am not totally sure of the problem as it appears quiet random, however after playing around a bit it appeared that it works better if I quickly stop and then start the vi again. To test this I placed the vi in a while loop and added a wait function. If this wait is 10ms the defect disappears, at 1sec it works about half the iterations, and at 10sec it occasionally works.

One thing I also noticed is that in IMAQdx Configure Grab VI the check if session in exists always returns true (so path isn't found) and the standard path (cam0) is sent. Now however, this is the same path that is inputted. So I suspect this might be a couse of the problem too.

Anyone have any ideas on how to solve this? Help is greatly appriciated.

[ThiCop]

Hello Pindakaas,

Have you checked with the support of Trust (the camera manufacturer) that this camera is DirectShow Compliant?

This is the first thing we should verify.

We also need to gather as much information as possible about your hardware/software set-up.

Can you also share a MAX Report with me?

This can be created the following way:

http://digital.ni.com/public.nsf/allkb/271F252B4EF0A2E0862570E70056A1E4?OpenDocument

Please create it when the camera is connected.

I have some problems in opening your VI.

Can you tell me if this example works correctly (this is just a basic example, but will show if the camera works on itself correctly)?

https://decibel.ni.com/content/docs/DOC-31956

[Pindakaas]

Hello ThiCop,

Thanks for your reaction, in The max it is showing that the camera connection is DirectShow. I have rebooted my pc so I could give you a clean MAX report (plugged in webcam after windows booted). This is the ni_support.zip. Here all camera Attributes show and can be edited at will (I think this is the sometimes that my program does work). Then I closed the MAX and reopened it (you could see it check for the webcam again and it was found again) this is the second report, here the camera attributes do not show.

I tried opening your reccomended vi to test it but as I have labview 9.0 (student edition) I was unable to open it. I have however used the NI examble Grab and basic attributes.vi and here it worked after rebooting the pc. Stopping and restarting the program makes the vi stop being able to edit the attributes (still getting image though). As said before I suspect it might have something to do with time between starting and stopping the VI. If I place a grab and read attribute configuration in a while loop (so that the camera is configured and stopped multiple times) it appears that with a short wait (so a short time betueen the stopping and restarting) it works more often then with a long wait. Here the long wait still shows a immage if the attributes are not shown.

Although it might seem like a strange problem I hope you can help me further. Just ask for more info if I have not suppied enough.

Thanks in advance

[ThiCop]

Hello,

Can you reproduce the same issue with the Asus Webcam that's mentioned in your MAX Report?

Or does it only occur with this specific webcam?

[Pindakaas]

Indeed the asus webcam is giving the same problem. Not really much of a clue what could be the problem. 

[ThiCop]

Hmmm,

I'm quite curious to see if you can reproduce the issue with a newer version of the IMAQdx driver.

Can you try to reproduce this behaviour with a more recent version of the driver?

http://www.ni.com/download/ni-vision-acquisition-software-2013.02/3818/en/

I think this version is compatible with LabVIEW 2009 SP1.

Thanks in advance for the troubleshooting together with me!

[Pindakaas]

I installed the drivers, but there's still a problem. I get the feeling that it works less often but I cannot confirm it 100%. I have at least confirmed cases where it worked and where it didnt.

[ThiCop]

Hmm,

Is the frequency the same for both USB-camera's?