Rockwell Automation 5370-CVIM2 Module - Manual (Page 63)

Chapter 3
Image Acquisition Parameters
3–24
Figure 3.16 Example: Performing Nominal or “Learn” Operation
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Note that the distance between the Feature A and B offsets –– the Nominal
value –– is 382.983 pixels. Note also that the Scale value is now 0.0026,
which is the ratio of the current Dimension value (1.000, the default value)
to the current Nominal value (382.983). Thus, 1
B382.983 = 0.0026 (this is
rounded to four places for display purposes only; the actual value, stored in
memory, is based on 32–bit floating point calculations).
To complete the scale computation, and thereby calibrate the distance
between the Feature A and B offsets to the “world units” distance of 2.000
inches (in this example), pick the
Dimension field. When you do, the
“calculator pad” appears. Enter 2.000 in the calculator and pick the
button. At that point, the
Scale value will be recomputed, and will appear as
“0.012” in the Scale field, as shown in Figure 3.17 (page 3–25).
After completing the scale computation for one calibration gage, repeat the
process for the other gage.
After completing the scale computation for both calibration gages, pick the
button to exit the Calibrate panel and return to the selected Camera
setup panel. Subsequent linear measurements by gages using images from the
selected camera will be returned in inches (in this example).