Operator
’s Guide
Appendix M
003-4500
RJS, Minneapolis, MN
111
Edge Contrast (EC) See Edge Contrast(min)
The difference between the space reflectance (Rs)
and adjoining bar reflectance (Rb).
EC = Rs - Rb
Edge Contrast (min)
This parameter grade can be
“A” or “F.” Edge
contrast is the Reflectance difference between
adjoining bars and spaces. The minimum edge
contrast is the smallest value of EC = R space
–
R
bar found in the scan.
The grade is determined by calculating the edge
contrast of every element in a symbol and then
comparing the lowest value to a fixed threshold in the
specification (15%).
If the value is equal to or greater than the threshold,
the grade is
“A.” If the value is less than the
threshold, the grade is
“F.”
Element
A generic term used to refer to either a bar or space
in a bar code symbol.
Element Edge
The location where the scan reflectance profile
intersects the midpoint between the space reflectance
(R space) and bar reflectance (R bar) of adjoining
elements. Visual measuring techniques will generally
locate the element edge closer to the center of the
bar.