Hardware manual

Impact Reference Guide Blob
3-147 Datalogic Automation Inc.
Blob
See “Blob” on page 3-66
Bump Find
In the Flaw Detection Drawer
The Bump Find Tool analyzes a polygon list for bulges in the boundaries. Use the Polygon Smoothing tool
(page 3-153) to smooth the polygon list before you use the Bump Find tool.
The tool distinguishes between a bump or bulge defect and polygon corners or noise based on the input
parameters. Smoothing reduces image noise to a low enough level so that edge variability due to noise may
be reduced and defects stand out. However, too much smoothing renders defects undetectable.
Cumulative turn angle and flatness length settings also help filter noise. Turn angle describes the amount of
angle change (in opposite directions) that is needed between boundary edges to indicate the beginning and
end of a defect point. The end of a defect is indicated by a stretch of flat boundary. The boundary is consid-
ered flat if an edge change does not exceed the minimum turn angle.
Flat areas may exist within a defect, but when the length of that flat area is longer than the flatness value, the
defect is considered terminated. The flatness length value should be small enough to terminate defects on
any clean edge, but large enough that defects do not terminate prematurely. Note that corners near defects
are often considered as part of the defect (since the flatness length is not exceeded in this case) but this
should not cause a problem.
Minimum area is the smallest area within a string of defect points that indicates a defect. If the area range
value is not exceeded before the end of a defect, those points are not reported as defects.
The Defect Point Count list indicates how many points are in each defect. This means individual defects can
be separated. For example, if the Defect Point Count list contains 3, 4, 5, the first three defect points corre-