Rockwell Automation 5370-CVIM2 Module - Manual (Page 250)

Chapter 7
Inspection Tools
7–12
Gray Scale Gaging Mode: Background Objects
Background objects are those objects that lie completely between the first and
last detected edges, and whose pixels are darker than the adjacent pixels ––
the pixels on both sides of the object. (Note that the edges stand out as a
consequence of the settings for edge detection parameters.)
Example (A) of Figure 7.10 is a straightforward example in which five
background (dark) objects are identified that correspond to the five black
rectangles.
Figure 7.10 Examples: Counting Background Objects (Gray Scale)
A
B
Example (B) of Figure 7.10 is a more complex example in which four
background (dark) objects are identified. The first three background objects
pertain to the three darkest rectangles, since the pixels within each of these
rectangles are darker than the pixels adjacent to each rectangle. The fourth
“object” includes the second of the first three objects; that is, the second
object is “nested” inside the fourth object.
Figure 7.11 (page 7–13) uses a graph to illustrate the relative gray scale
values along the gage, and to demonstrate that both sets of objects satisfy the
definition that a background object is one whose pixels are darker than the
adjacent pixels. Thus, object 2 in this example is nested in object 4.