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Problem connecting webcam with dialogue box


Hi Folks.


I have the following vi which opens a webcam window and grabs a frame and saves it. It uses dll's instead of imaq. It works well except for some weird connection issues.


When I run the vi the dialogue box (shown below) appers and I select my VGA USB Camera but the image is black. However when I unplug and re-insert the camera cable and run the vi the video feed appears and there is no selection process. It is as if there is some sort of memory somewhere.


If I choose the other default cameras it is displayed (its actually a grey box because they are disabled) so connects straight away but then I cant remove it and select another without rebooting the machine.


Does anyone know how I can reslove this strange behaviour?








Dialogue Box.png

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Well, the dialog that you get is not a LabVIEW box. It appears to be coming from the DLL -- which leads me to question whether this is a LabVIEW problem. Does the camera vendor have a support site? I think that is where I would start asking questions. It sounds like something isn't getting initialized correctly.

Who is the vendor?


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The camera is: elp-usb30w02m

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My guess is that IMAQdx "Snap" should have no problem returning you an Image.  If you want to use third party software to do this, see if the Vendor has a Support site ...


Bob Schor

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Ahh, I thought the name was familiar.  You posted earlier "Using USB Camera without using IMAQ", and were encouraged to use IMAQ ...  Advice still stands.  Yes, there may be an additional cost, but how much is your time and effort worth, particularly if you aren't making progress?



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The code does work from a labview point of view. The video source is an operating system thing. I have a similar program using C++ and have the same connection issue There is a lot of similar issues over the web but no real solution. Thought someone here may have seen it before. Alternatively it may well be a dodgy camera.

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As it turns out it was the camera. The internal camera works fine. As a workaround I just put in a few reconnects. Its not ideal but will do for now.

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