Omron F250-UME Software Manual page 311

Density Defects
HELP
CHECK
2-14-2-2 Defect (Variable Box)
element size is reduced and less sensitive (and the processing time short-
er) if the element size is increased.
Example
Element
Defect
Sensitivity
Processing
time
If density that is not part of the defect is included in the calculations as
shown in (2), the differences with areas that are not part of the defect will
be reduced. In other words, the more the background is included in the el-
ement, the weaker the sensitivity will be.
Comparing Pitch
Determine the comparing pitch based on the size of the defects and the
size of the elements. The larger the comparing pitch, the shorter the pro-
cessing time will be.
• If the element size is larger than the defect size, set a smaller compar-
ing pitch. To find line-shaped defects, set it to about 1 or 2.
• If the defect size is larger than the element size, set a somewhat larger
comparing pitch. If the comparing pitch is too small, comparisons will
be made for elements on the edges of defects, reducing the defect val-
ue.
Differences That Depend on the Shape of the Region
Shape of region
Line, circumfer-
Element
ence, or arc size
defects
Region defects
Element
size
The Defect (Variable Box) measurement method measures defects while
adapting the measurement region to suit measurement objects with inconsis-
tent sizes and positions.
First, the upper, lower, left, and right edges of the measurement object are
located. The area within the edges becomes the measurement region.The
location of the measurement object can be determined using the edge detec-
(1)
Strong
Long
Element size
Depends on
measurement
region size
Element size
Section 2-14
(2)
Weak
Short
Comparing direction
Left, right
Up, down, left, right
2-14-(13)