Download National Instruments IMAQ Vision for LabWindows TM /CVI User's Manual

Chapter 6
Calibrating Images
x
1
y'
x
x'
2
y
y
1
Default Origin in a Calibration Grid Image
2
User-Defined Origin
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 imaqLearnCalibrationGrid().
Note If you want to specify a list of points instead of a grid, use
imaqLearnCalibrationPoints() to learn the calibration information. Use the
CalibrationPoints structure to specify the pixel to real-world mapping.
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IMAQ Vision for LabWindows/CVI User Manual