KEYENCE SR-750 Series - Manual (Page 22)

22 E SR-750 UM
Modulation MOD (Modulation)
Description
Evaluates the variation degree in cell
brightness
― Calculation
formula
Each cell's MOD = 2 ½ (abs (R-GT)/SC)
R : Brightness value
GT : Binarization threshold value
SC : Symbol contrast
Criterion ―
Reflectance margin RM (Reflectance Margin)
Description
Evaluates the variation degree in cell
brightness with black and white of the correct
cell considered.
―
Calculation
formula
[White cell]
R >= GT
→ MARGIN = 2 ½ (R-GT)/SC
R < GT → MARGIN = 0
[Black cell]
R < GT
→ MARGIN = 2 ½ (GT-R)/SC
R >= → MARGIN = 0
MARGIN : Margin of each cell
R
: Brightness value
GT : Binarization threshold value
SC : Symbol contrast
Criterion ―
Fixed pattern damage FPD (Fixed Pattern Damage)
Description
Evaluates the degree of the fixed pattern
damage (area on the right) dependent on the
code type.
Calculation
formula
―
Criterion ―
Format information damage
FID
(Format Information Damage)
Description
Evaluates the format information damage
degree of QR code.
Calculation
formula
―
Criterion ―
Version information damage
VID
(Version Information Damage)
Description
Evaluates the version information damage
degree of QR code (Model 2, version 2 and
later versions).
Calculation
formula
―
Criterion ―
Axial nonuniformity AN (Axial Nonuniformity)
Description
Evaluates the distortion degree in vertical and
horizontal size of the code.
Calculation
formula
AN = abs (Xavg = Yavg)/((Xavg = Yavg)/2)
Xavg : Average cell size in horizontal
direction
Yavg : Vertical cell size in horizontal
direction
Criterion
A : less than 0.06
B : 0.06 to 0.08
C : 0.08 to 0.10
D : 0.10 to 0.12
F : more than 0.12
Grid nonuniformity GN (Grid Nonuniformity)
Description
Evaluates the maximum position slip of each
cell
Calculation
formula
GN = Hmax/X
Hmax : Maximum position slip amount
X
: Cell size
Criterion
A : less than 0.38
B : 0.38 to 0.50
C : 0.50 to 0.63
D : 0.63 to 0.75
F : more than 0.75
Unused error correction
UEC
(Unused Error Correction)
Description
Evaluates the ratio of error correction unused
at the time of decoding.
―
Calculation
formula
UEC = 1.0 - ((e + 2t)/(d - p))
e : Number of code words that cannot be
read
t : Number of error code words
d : Number of error corrected code words
p : Number of error detected code words
Criterion
A : more than 0.62
B : 0.50 to 0.62
C : 0.37 to 0.50
D : 0.25 to 0.37
F : less than 0.25
Print growth (horizontal)
PGH
(Print Growth Horizontal)
Description
Evaluates the mark cell growth in the
horizontal direction.
Calculation
formula
(D - 0.5)/0.15
D : On the horizontal clock pattern
Ratio of the number of pixels of mark
cell
Criterion
A : -0.50 to 0.50
B : -0.70 to -0.50 or 0.50 to 0.70
C : -0.85 to -0.70 or 0.70 to 0.85
D : -1.00 to -0.85 or 0.85 to 1.00
F : less than -1.00 or more than 1.00
Print growth (vertical) PGV (Print Growth Vertical)
Description
Evaluates the mark cell growth in the vertical
direction.
Calculation
formula
(D - 0.5)/0.15
D : On the vertical clock pattern
Ratio of the number of pixels of mark
cell
Criterion
A : -0.50 to 0.50
B : -0.70 to -0.50 or 0.50 to 0.70
C : -0.85 to -0.70 or 0.70 to 0.85
D : -1.00 to -0.85 or 0.85 to 1.00
F : less than -1.00 or more than 1.00