National Instruments IMAQTM - Manual (Page 90)

Chapter 6 Calibrating Images
© National Instruments Corporation 6-5 IMAQ Vision for Visual Basic User Manual
Figure 6-4. Defining a Coordinate System
Learning Calibration Information
After you define a calibration grid and reference axis, acquire an image of
the grid using the current imaging setup. For information about acquiring
images, refer to the
Acquire or Read an Image section of Chapter 2, Getting
Measurement-Ready Images . The grid does not need to occupy the entire
image. You can choose a region within the image that contains the grid.
After you acquire an image of the grid, learn the calibration information
by inputting the image of the grid into
CWIMAQVision.LearnCalibrationGrid .
Note If you want to specify a list of points instead of a grid, use
CWIMAQVision.LearnCalibrationPoints to learn the calibration information.
Use the CWIMAQCalibrationPoints object to specify the pixel to real-world mapping.
1 Default Origin in a Calibration Grid Image 2 User-Defined Origin
x
y
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2
y'
x'
y
x