Rockwell Automation 5370-CVIM2 Module - Manual (Page 449)

Chapter 8
Thresholds, Filters, and Morphology
8–10
Figure 8.7 Example: Effects of Changing Low Threshold (Constant High Threshold)
A B
C D
Binary Threshold Function (Count Black Pixels Operation Only)
When you use the black pixel–counting window operation, the thresholds
work in the opposite sense from that of the other binary window operations.
This means that workpiece features that are dark on a light background in the
raw, gray–scale camera image are inverted so that they appear white on a
black background in the window’s binarized image. The pixels that appear
white are the pixels that will be counted.
High threshold –– Any part of that image whose gray–scale brightness value
is higher than the high threshold value will appear white in the window. For
example, if the high threshold is 190, any part of the image whose brightness
value is higher than 190 will appear white in the window.