Rockwell Automation 5370-CVIM2 Module - Manual (Page 207)

Chapter 6
Reference Tools
6–48
Nominal (“Learn”) Function
As noted on page 6–28, the Nominal field in the reference window tool edit
panel, when picked, causes the currently selected and configured reference
window tool to store the “nominal” position of the X and Y coordinate data,
as well as angular data, and to display that data in the
Nominal field.
Additional data appears in a Feature Locations panel.
When you pick the Nominal field, the Feature Locations panel appears on
the display, and the feature and search windows lie over the image, as shown
in Figure 6.40.
If one feature is active (Feature A or Feature B), the X and Y coordinates
(under the
Location heading in the Feature Locations panel) identify the
location of the upper–left corner of the single feature window.
If two features are active (Feature A and Feature B), the X and Y coordinates
identify the location of the midpoint on a line connecting the upper–left
corners of the two feature windows. Figure 6.40 illustrates the appearance of
the
Feature Locations panel when both features (A and B) are active.
Figure 6.40 Example: Feature Locations Panel
Feature A
search window
Feature B
search window
Feature A
feature window
Feature B
feature window
The three columns in the Feature Locations panel are defined as follows:
•
Rank –– This identifies the feature as follows: When only one feature (A
or B) is used, it always appears as rank 1. When both features (A and B)
are used, rank 1 pertains to Feature A and rank 2 pertains to Feature B.
(The currently highlighted feature in the panel corresponds to the green
feature window in the image field.)
•
Location –– This identifies the X and Y coordinates of the upper–left
corner of each feature window.
•
RMS Error –– This displays the calculated RMS (root mean square)
error for each feature (refer to the Pixel Error Parameter Selections
section on page 6–43 for details about RMS error calculations).