Rockwell Automation 5370-CVIM2 Module - Manual (Page 272)

Chapter 7
Inspection Tools
7–34
White Contours; Black Contours
These two operations identify black or white objects within the window
boundaries. The image is binarized into groups of black and white features
called contours, and each contour can be analyzed on the basis of its area,
shape, orientation, and/or other physical characteristics.
A contour window counts all contours whose color (black or white) and
selected physical measurements qualify them as objects.
The inspection result is the number of contours that qualify as objects. For
example, if a window contains 18 black features, but only 12 satisfy all of
the measurement limits, the result from the contour operation will be to
identify and count 12 objects.
Figure 7.31 shows a window using the black contours operation to count the
number of black objects within the window’s boundaries.
Figure 7.31 Example: Using the Contour Operation
For the purposes of this discussion, an object is a contour whose area and/or
other measurement criteria meet user–specified limits.
White object: a group of contiguous white pixels surrounded by black
pixels (within the window boundary).
Black object: a group of contiguous black pixels surrounded by white pixels
(within a window boundary).
Both objects can range in size from one pixel to the total number of pixels in
the window.