Cognex DataMan - Page 43

Property Type 1DStandards 2D Standards Description
gridNonUniformity
Metric ISO/IEC15415
(DataMatrix, QR,
DotCode), AIM/DPM
ISO/IECTR-29158
(DataMatrix, QR)
The grid non-
uniformity. Grid non-
uniformity measures
the difference
between the optimal
placement of cells
based on the overall
grid and their actual
placements. This is
similar to the axial
non-uniformity
measurement, but
instead of measuring
a stretching or
compressing of the
whole grid, this
measures how much
the individual cells
deviate from their
expected positions.
Poor grid non-
uniformity usually
indicates a printing
process which is not
consistent in its
placement of the cells.
extremeReflectance
Metric ISO/IEC15415
(DataMatrix, QR)
The extreme
reflectance. This
metric measures the
brightness of the
background on which
the code is printed. A
too high value might
indicate lighting or
imaging trouble that
could lead to a code
being washed out and
difficult to read. A low
value may indicate
that not enough light
is being applied to the
code, and that
contrast may be poor,
leading to difficulty in
reading. A poor
extreme reflectance
grade may also
indicate trouble
relating to the
positioning of lights
such as hotspots.
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DataMan Application Development