Omron F250-UME Software Manual page 616

Density Data
2-28 Density Data
2-28-(1)
The Density Data processing item can be used to inspect for the presence of
the measurement object.
The Density Data processing item detects the density of each pixel (0 to 255)
and calculates the density average and deviation to be used for inspection.
Because the density deviations are compared, the effects on inspection of
dark images can be reduced, e.g., when illumination deteriorates.
Example: Inspecting for the Presence of Electronic Components
Two measurement regions are set: One in the area where the electronic
component is and one on the background. The difference between these
regions is used to check for the presence of the component.
Component
Average density: 30
Component (missing)
Average density: 190
Good Product
Background
Average density: 200
Difference in density: 170
NG Product (Part Missing)
Background
Average density: 200
Difference in density: 10
Section 2-28