l
ANU (Axial Non-uniformity)
is the amount of “out of square” the modules are, that is, a measure of the overall
aspect ratio of the symbol. For rectangular symbols which are supposed to be non-square, the ANU parameter
reports the deviation from its “correct” aspect ratio.
ANU %
Grade
≤ 6
A (4.0)
< 8 (but more than 6)
B (3.0)
< 10 (but more than 8)
C (2.0)
< 12 (but more than 10)
D (1.0)
> 12
F (0)
l
GNU (Grid Non-uniformity)
is the worst-case distance between the calculated center of a module and the ideal
location for the center of the module based on perfectly evenly spaced modules. The calculated center of the
module is determined using clock track edges in accordance with the reference decode algorithm. The value is
reported as a percentage of a module size.
GNU %
Grade
≤ 38
A (4.0)
< 50 (but more than 38)
B (3.0)
< 63 (but more than 50)
C (2.0)
< 75 (but more than 63)
D (1.0)
> 75
F (0)
l
FPD (Fixed Pattern Damage)
is the overall grade for all the fixed pattern components. This grade is equal to the
lowest grade of all the components listed below. The following is a list of components of the finder pattern for
Data Matrix symbols. For QR Code symbols, the parameters described in ISO 18004 QR Code Grading
Parameters on page 1 are applicable.
l
LLS (Left ‘L’ Side)
is a grade based on imperfections in the left ‘L’ side of the finder pattern. There are two checks
required to pass. The first requires gaps to be three modules or less and that gaps are separated by stretches of
at least four correct modules. The second assigns a grade based on the overall percentage of correct modules
according to the following table:
% of incorrect modules
Grade
0
A (4.0)
< 9 (but more than 0)
B (3.0)
< 13 (but more than 9)
C (2.0)
< 17 (but more than 13)
D (1.0)
> 17
F (0)
The grade is the highest modulation level in which the first (gap test) passes and the correct module percentage results
in a grade of that level or higher.
l
BLS (Bottom ‘L’ Side)
is a grade based on imperfections in the bottom ‘L’ side of the finder pattern (see Left ‘L’
Side).
l
LQZ (Left Quiet Zone)
is a grade based on imperfections in the quiet zone, which is a one-module area to the left
of the left ‘L’ side. The grade is based on the percentage of modules, which are correct using the same grading
table as for the ‘L’ sides.
l
BQZ (Bottom Quiet Zone)
is a grade based on imperfections in the quiet zone, which is a one-module area
below the bottom ‘L’ side.
40
Grading Standards and their Parameters