Discussion:
Creating a Calibration Grid for Measurement Studio
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mastada
2005-07-12 14:10:47 UTC
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Good day.
 
Well another on on the Forum. Lets see what we can do.I'm using Measurement Studio and all the CWIMAQ Controls and I want to Create my own calibration grid using the
CWIMAQVision1.LearnCalibrationPoints method. I've already been doing some stuff with a grid graphic and setting the Dx and DY. That works. But now I want to Pick the Pixel Points and Pick supply the Real World X and Y for each point. As is described just better than vaguely in the IMAQ manuals. One.... How many points do I need to supply to get a decent "Learn Score" from LearnCalibrationPoints? And Exactly how does the LearnCalibrationPoints work? I presume that it just interpolates somehow for all the pixels between the points selected?
Here is my App. (Plan). I have an image take from a Ship (Sea going ship) looking out to the horizon. The horizon could be as far as 6 mile away. But I am wanting to create a grid that is perhaps out to 500 feet and possibly 200 feet wide. I can supply many points for this region of my image, then I am perhaps less precise with point that describe the perimeter of the image out to the Horizon. I can solve distance out to the horizon mathematically, and then I can solve the distance across the left and right of the image at the Horizon with math. All calibrated with perspective.
I've attached a picture. You'll see 19 points supplied to pixel image therefore 19 different real world positions, all relative to each other.
 
 
Please let me know if this will work. The LearnCalibrationPOints should pull it off, as I want to make a powerful user defined tool with the NI tools.
 
Thanks for the help on previous threads.


UserCalibration.jpg:
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LMEE
2006-09-19 21:40:09 UTC
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Robert,
 
You mentioned, "You can also perform this same process in LabVIEW, it's just a little more involved to set up."  I am attempting to do this in LabVIEW.  Could you please tell me how to do this?  I am using LabVIEW 8.2.
 
Thanks!
 
LMEE
CMal
2006-09-21 14:10:10 UTC
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LMEE,
 
There are some examples in LabVIEW that should be helpful in getting you started with calibrating images.  You can find them in the LabVIEW directory:
Examples\Vision\2. Functions\Calibration\Perspective Calibration Example.llb
Examples\Vision\2. Functions\Calibration\Simple Calibration Example.llb
Examples\Vision\2. Functions\Calibration\Nonlinear Calibration Example.llb
 
Please let me know if you have any specific questions on these examples.
 
Chris
Applications Engineer
National Instruments
<a href="http://www.ni.com/support" target="_blank">http://www.ni.com/support</a>
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