Rockwell Automation 5370-CVIM2 Module - Manual (Page 269)

5 Chapter Chapter 7
Inspection Tools
7–31
NOTE: The destination window is normally configured with the vertical
axis longer than the horizontal axis, since the unwrapped image data is
displayed vertically. The aspect ratio of the destination window should be
adjusted as needed to optimize the appearance of the part or item being
inspected.
In operation, the arc ring window processes (and “unwraps”) the image area
lying between the inner and outer rings of the image window, then displays
the unwrapped and processed image vertically in the destination window.
Figure 7.27 is an example that illustrates using an arc ring window to detect a
flaw in a can lid. In this example, the image window is centered over the
circular lid, and the arc is positioned to exclude the wedge–shaped opening in
the lid, which is regarded as a normal feature of the lid.
Figure 7.27 Example: Using Arc Ring Window to Detect Flaw
Opening
in can lid
Flaw
Flaw
Note that the portion of the lid within the image window has a slit in it,
which is regarded a flaw in this example. The flaw also appears in the
destination window, which is positioned alongside to the left.
In this example, the window is configured to count black pixels, since any
flaw in the can lid would be recorded as black pixels. Ideally, no black pixels
would be detected, and the black pixel count would thus be zero. As
Figure 7.27 shows, however, the flaw has resulted in a black pixel count of
303, which appeared in the
Nominal field following a “learn” operation.