National Instruments IMAQTM - Manual (Page 96)

Chapter 6 Calibrating Images
© National Instruments Corporation 6-11 IMAQ Vision for Visual Basic User Manual
CWIMAQVision.ConvertPixelToRealWorldCoordinates . If
the application requires shape measurements, correct the image by
removing distortion with
CWIMAQVision.CorrectCalibratedImage .
Note Correcting images is a time-intensive operation.
A calibrated image is different from a corrected image.
Note Because calibration information is part of the image, it is propagated throughout
the processing and analysis of the image. Methods that modify the image size,
such as an image rotation method, void the calibration information. Use
CWIMAQVision.WriteImageAndVisionInfo to save the image and all of the attached
calibration information to a file. If you modify the image after using
CWIMAQVision.WriteImageAndVisionInfo , you must relearn the calibration
information and use CWIMAQVision.WriteImageAndVisionInfo again.