RJS Inspector D4000 Auto Optic (FIRMWARE version A.05 and Earlier) - Manual (Page 63)

Operator
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s Guide Appendix J
002-5564 RJS, Minneapolis, MN 56
(Bar-code colors can have a large effect on this parameter.)
Refl (Min)/Refl (Max)
This parameter grade can be “A” of “F.”
The reflectance value of the “lightest” space must be at least twice as great as the reflectance
value of the “darkest” bar, otherwise, the grade will be “F.”
Edge Contrast (Min)
This parameter grade can be “A” of “F.”
Edge contrast is the difference of the reflectance values of the dark and light components of
an edge.
Each element of a bar-code has two edges which go from dark to light. Therefore, each edge
has a dark and light reflectance value component.
The parameter grade is determined by:
1.
calculating the edge contrast of every element edge in a symbol
2. finding the lowest value (minimum edge contrast)
3. comparing it to a fixed threshold in the specification (15%)
If the value is at least as great at the threshold, the grade is “A,” otherwise the grade is “F.”
Modulation
This parameter can also be “A,” “B,” “C,” “D,” or “F.”
Modulation grade is based on the relationship between the minimum edge contrast and the
symbol contrast.