Omron F250-UME Software Manual page 274

Detecting Binary Defects
2-12-(31)
The Detailed Conditions Settings Screen will be displayed.
Left edge
b) Move the cursor to the condition to be changed and change the set-
ting.
c) Select End.
The settings will be registered and the screen in (a) will return.
Press the ESC Key to return to the initial screen for Area (var. box).
Edge Level
Set a density change level between 0 and 100 that will indicate the edge. Nor-
mally, the default setting of 50% will be fine.
The edge is normally detected as follows:
1. The density distribution of the whole measurement region is calculated.
2. The density difference between the lowest and highest density value be-
comes 100%.
3. The point where the edge level density change is detected becomes the
edge.
Measurement region
Noise Level
Set a noise level between 0 and 255 to assist the determination of edges. The
maximum density and minimum density within the edge detection area is cal-
culated and if the difference between the two values is less than the noise
level, then the Controller determines that there is no edge. Normally the
default setting of 20 is sufficient. Adjust this to a higher value, however, if noise
is causing false edges to be detected.
(Within the edge detection region)
Max. density - min. density < noise level
result
Max. density - min. density
Edge level : [ 50]%
Noise level : [ 20]
Noise width: [ 0]pix
Offset width: [ 0]pix
End
100%
50%
0%
no edge
noise level Edge
Section 2-12
Maximum density value
Edge level
Minimum density value
NG measurement
Used for measurement