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Does not display image

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I am using the vision software, Labview 2011 windows XP with a USB wbcam. I use the WebCam to test the software, create an installation file, and run it on a different machine. This machine has an IEEE 1394 Basler camera.

 

The program seems to work without any problem with the run-time system. On the USB system, the image never displays properly if I have a property node to read information from the camera. If I remove it, it works just like the IEEE 1394 camera.

 

The enclosed VI seems to demonstrate the problem. If you run it as is, it will not display the image. If you stop the program and set the property node to false, it will display the image properly.

 

 

 

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Message 1 of 7
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Try to change the execution order: Read the property nodes before executing the grab.

Does it work?

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Message 2 of 7
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No Luck before the grab. I think it is related to the way they handle usb camera and the other camera.

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Message 3 of 7
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Let's wait for an IMAQdx hero to chime in ...

A couple of years ago I had a similar issue with a camera that did not allow any read or write of properties when in grab mode.  Sorry for me not remembering any details.

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Message 4 of 7
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Hi Joseph,

 

Are you getting any particular errors, or is the image simply not appearing?  Are the VideoMode and FrameInterval displays updating, or remaining blank?  I don't currently have access to the model camera you are using and haven't been able to replicate the issue, so any more detailed information you can provide (screenshots, etc.) would really help with troubleshooting. It may also be worth posting on our Machine Vision forums, as the user base there might have more insight into the problem.

Tom L.
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Message 5 of 7
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The USB webcam seems to update the VideoMode to value of 4 (0 before). FrameInterval stays 0.

 

No errors appear during the run. When you terminate, the following errors appears.

 

The firewire camera, Bassler does not have the problem. It is the USB webcam that has this issue.

 

 

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Message 6 of 7
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Solution
Accepted by topic author Joseph_Loo

To see all the attributes supported by the camera, use IMAQdx Enumerate Attributes. If you do this, you'll notice that Frame Interval isn't one of them. Remove Frame Interval from your property node to get rid of the error.

 

If you want to determine the FPS of the current video mode, you can do so manually in your loop (by counting frames per second). To translate the video mode, use the property node (as you do now) and then use IMAQdx Enumerate Video Modes to get a list of all the possible video modes (and then using the output of the property node to index that list).

 

Not all cameras support all properties in the property nodes! Sorry!

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Message 7 of 7
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