Rockwell Automation 5370-CVIM2 Module - Manual (Page 412)

Chapter 7
Inspection Tools
7–174
Figure 7.140 Appearance of Threshold Adjustment Panel With Min+%Diff Low Mode
Min+Offset Mode
When you pick Min+Offset in the Thresh Mode panel, the Threshold
panel appears as shown in Figure 7.141 (page 7–175).
In this mode, the slide bar has two cursors (the
n and
High cursors) and two
corresponding fields (the Offset and Limit fields). The default value for the
“ Offset ” field is 128, and the default value for the “ Limit ” field is 255.
The Min+Offset threshold mode enables you to set up a dynamic threshold,
along with a maximum limit above which the threshold may not go during
run mode operation.
The concept of the Min+Offset threshold mode is this: The profile tool will
find the minimum gray scale values in the profile image, and then place the
threshold at a position that is equal to the minimum value plus the offset
value.
The practical effect is this: During run mode operations, the threshold will
automatically readjust itself whenever lighting and other external
circumstances change, but it will not exceed the high limit value.