Rockwell Automation 5370-CVIM2 Module - Manual (Page 55)

Chapter 3
Image Acquisition Parameters
3–16
*These expanded statistical results are available only when a tool is enabled
for statistics operations, as indicated by
Stats appearing in the Enabled
column for the corresponding tool.
Calibration Setup
This section discusses the calibrate function, which enables you to calibrate
the image field from each camera to inches, centimeters, or any other “world
units” of your choice, and perform linear gaging operations (such as linear
measure) in those units. Included in this discussion is a simple application
example whose main purpose is to demonstrate the procedure for using the
calibrate function.
The calibration function uses an X–axis and a Y–axis “gage” to detect the
edges across the X and Y axes of a calibration object, which is an object of
known dimensions. Each “gage” operates like a line gage performing a linear
measurement operation –– it returns a raw pixel count that you can then
calibrate to world units.
Calibration Applications
Calibration applies mainly to linear and circular gaging operations, using
linear measure, in applications that require uniform measurements of a
workpiece in the X– and Y–axes that are typically stated in “world units,”
such as inches and centimeters.
Other uses include applying the “scaling” values, which are derived from the
calibration operation, to a math tool formula set up to perform window area
measurements in world units.
Calibration: Basic Steps
Here is a summary of the basic calibration steps, listed in their normal order
of performance.
1. Set up calibration object image –– acquire a camera image of an object
of known dimensions to be used as the “calibration object” in the
calibration procedure.
2. Select calibrate function –– select the calibrate function in the
appropriate Camera setup panel.
3. Select calibration mode –– select the “ Computed ” or the “ Absolute ”
calibration mode.