Enhancing USB Camera Image Resolution in LabVIEW ‎04-09-2014 07:17 AM - edited ‎04-09-2014 07:46 AM

[Crazydriver]

I'm trying on all ways to set a different webcam resolution that the maximum.
With the acquisition express there is no way: I set the correct resolution from the menu (es 640x480), with the test button it works fine....then i click finish, the Express VI recompile....I start the VI and the resolution is back to the default!

Using the basic blocks (with the example Grab and Attributes Setup.vi) it works fine and I'm able to set the resolution.

I tried with two different webcams. With Labview 2010 it works.

Does anybody know if there is some problem with the new Vision Acquisition Express 2013?....a solution?

I attached my simple test VI.

Thanks

[m.amoruso]

Hi,

i don't found any open issues on Vision Acquisition Express 2013 about this behaviour. Can you try to convert your Express VI with right click on the vi and select Open Front Panel, in this way labview create e block diagram with low level functions. If you try to use this new VI what kind of results do you have?

It's possible that are needed a repair of "Vision Acquisition Express 2013" installer.

Bye

Mario

[Crazydriver]

Hi Mario,

I tried to convert the express VI and I have the same problem: the webcam acquires at maximum resolution because the express VI is recompiled with the wrong resolution settings and of course there are not options for change it (in the converted file).

Did you tried the express VI with a webcam changing the resolution with Labview 2013? It works in your computer?

I reinstalled Labview completly two times...is not a problem of corrupted software.

Bye.

Marco

[Crazydriver]

I still didn't find solutions!
I converted the Express VI and by analyzing the subVIs I found that there is a string with the correct settings as input of the "IMAQdx read attributes from string.vi".
May be that the conversion goes wrong and the following subVI (IMAQdx configure grab.vi) receive wrong settings.
The "IMAQdx read attributes from string.vi" is a closed VI....can somebody check the correct functioning of this piece of library?

[MikaelLindgren]

Re: Enhancing USB Camera Image Resolution in LabVIEW

‎04-09-2014 07:17 AM - edited ‎04-09-2014 07:46 AM

I have noted the same problem with changing the resolution through Vision Acquisition Express VI.

I am using a Logitech 910 USB camera. Using NI MAX I can change the resolution, also from inside the Express VI I can change it and show it, but when I exit and run the program it will still only record the maximum image size, which is too big for me.

I solved it by converting the Express VI to a regular VI. Then went into the beginning of the VI and used Enumerate Video Modes to check which number you want. I used 17 for 640 x 480 RGB24. Then create a Property node: Video Mode for the Image Session, change to write and assign the constant 17 to it. Then it worked.

I suspect there must be a bug somewhere in the Vision Acquisition Express VI or more likely in one of its subVIs.

See also topic: How to adjust the resolution in a VI (NI-IMAQdx) ?

and topic: Enhancing USB Camera Image Resolution in LabVIEW

[MikaelLindgren]

I have noted the same problem with changing the resolution through Vision Acquisition Express VI.

I am using a Logitech 910 USB camera. Using NI MAX I can change the resolution, also from inside the Express VI I can change it and show it, but when I exit and run the program it will still only record the maximum image size, which is too big for me.

I solved it by converting the Express VI to a regular VI. Then went into the beginning of the VI and used Enumerate Video Modes to check which number you want. I used 17 for 640 x 480 RGB24. Then create a Property node: Video Mode for the Image Session, change to write and assign the constant 17 to it. Then it worked.

I suspect there must be a bug somewhere in the Vision Acquisition Express VI or more likely in one of its subVIs.

See also topic: How to adjust the resolution in a VI (NI-IMAQdx) ?

and topic: Enhancing USB Camera Image Resolution in LabVIEW

[reitzrabie]

Steps

1. Convert express VI to regular VI
2. Go to first VI inside case structure = True
3. Place Property node after open camera bloack
4. change property node to CHANGE ALL TO WRITE
5. Select Acquisition Attributes to - Video Mode
6. Place constant number value and link to Video Mode in property node
7. After property node place ENUMERATE VIDEO MODE
8. Connect Session out from open camera vi to enumerate video mode
9. create indicator at current mode from enumerate video mode

code attached

[RafaelMeneguelli]

Can you please send the same VI above to me, in an older version? I'm using labview 2012 and I cant open the VI that u sent,Thanks!

[reitzrabie]

You will need this

[reitzrabie]

Hi

version 12.0