Appendix K
Operator
’s Guide
RJS, Minneapolis, MN
002-7858
52
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 co
ntrast 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 re-
flectance (R space) and bar reflectance (R bar) of adjoining elements. Visual measuring tech-
niques will generally locate the element edge closer to the center of the bar.