Converting Pixels into Real World Measurments

[kbaker]

I am trying to convert my images from pixels into real world measurements and I was wondering if anyone had any good advice on how to do this? I am using a IR camera and an IR light source. I was thinking of simply making a piece of paper with 2 vertical lines a known distance from each other, and then making sure it was in the same image. I am not sure how well the IMAQ Convert Pixel to Real World works? Should the lines have to be narrow or broad? Is there a better way to do this? Thank you in advance for any advice.

[Aaron B.]

Hello,

If you open the "IMAQ Vision for LabVIEW VI Reference Help" and navigate to "Vision Utilities >> Calibration VIs >> IMAQ Convert Pixel to Real World", you will see from the general description of this VI that your calibration information is attached to the image by "IMAQ Learn Calibration Template.vi", "IMAQ Set Simple Calibration.vi", or "IMAQ Set Calibration Info.vi". If you are using the first one, then the template image should be a grid of dots rather than a grid of lines.

I would recommend opening up one of the three examples of calibrating that can be found at "C:\Program Files\National Instruments\LabVIEW 7.1\examples\Vision\2.Functions\Calibration". I hope you find these examples useful. Take care!


Regards,

Aaron B.
National Instruments