Trouble producing calibrating image in labview vision assistant

[rharker@chem.ufl.edu]

Using the calibrate image wizard in Vision Assistant 7.1.0 build 20040824105755.

My calibration image is a 480x640 pixel grid of 9 pixel dots separated by ~36pixels.  The original pattern is a grid of .5mm black dots on white.

No dot intersects an edge of frame and the entire frame is filled.  I used the grid calibration non-linear threshold min 0 - 255max because my image is is only black and white.

When executing the final "OK" where it asks for a filename afterwards is says:

"An error occured an an unidentified location, or this error code is not listed in the internal database."

Thanks,

Robert Harker

[J.Harv]

Robert--

      For the calibration threshold you might want to try and change it from 0-255 to 0-128.  If the image is black and white then all of the values are between 0 and 255 so if you set that as your threshold it will cause an error.  First, change that, if it doesn't help post back and let us know and we'll see what we can do.

Regards,

John H
Applications Engineer
National Instruments
http://www.ni.com/support

[rharker@chem.ufl.edu]

John;

No-Joy on 0,128.

Do the calibration files have to be saved in any particular location because it seems to fail instantly at save?

Do the dots have to have an ellipsoidal shape or can they be round as long as the pattern shows the lens distortion.  I can't see how since circles at 9 pixels wide really are not circles but are really  9x9pixel squares missing 3pixels on each corner.

I made my calibration image by hand from a .5x.5mm ruled line grid and used photoshop to put dots at each crossing 9 pixels wide so the software is is likely to find the dot center exactly vs if it were an odd number of pixels the pick will always be a minimum of 1/2 pixel off.

It says in the book that the dots should be 6-10pixels wide space ~ 30pixels.  My dots are 9pixels and space ~36pixels.  The was the best I could do for my rig since if I changed the focus to get the smaller spacing the calibration would not apply to the properly focused images.

Are there any enhancements in the newest V8 software for calibrating images that would make it worthwhile going to the trouble installing?

Thanks for the help;)

Robert,

[J.Harv]

Robert--

      I was actually able to reproduce this today.  Which will definately help me here while trying to track down the issue.  In answer to your question about Vision Assistant 8.0, the problem does not occur with this version. However, upgrading Vision Assistant to 8.0 you would need to upgrade to the latest version of Vision (Vision Development Module), 8.2. If you are interested in an upgrade you could get advice and quotes by calling a sales represenative at (888) 280-7645.
     I'm going to continue to look into this and hopefully we can figure out what is going on. I'll post back to this thread as soon as I have any new information to add.

Regards,

John H
Applications Engineer
National Instruments
http://www.ni.com/support

[rharker@chem.ufl.edu]

I recieved the new media for the newest version today.  Installing now.  I'll let you know how it goes with 8.2.

Robert H.

[rharker@chem.ufl.edu]

You are correct.  An interesting thing about it is that the system appears to highlight the black dots to appear as red before the final calibration step.  That part is missing in 7.1.

Thanks for the help

Robert