Fujitsu M3097DG Oem Manual page 35

Image Functions
(1)
Pre-filter
[A.4.7 SET WINDOW command / DTC mode]
The pre-filter performs filtering before processing the Dynamic Threshold. Ordinary and Ball-
point Pen are selectable in Pre-filter.
Name of
parameter
Ordinary
High Contrast
Use Ordinary basically. For the texts written by ball-point pens, use of Ball-point Pen may better
for OCR. This is because, the texts written by ball-point pens actually have two thin lines per
stroke. To human eye, this is not big problem, but OCR may not recognize the text. The Ball-
point Pen filter detects lighter areas compared to the surroundings and increases the density of
the lighter area. puts these two lines into one solid line. This can prevents cuts, void or too thin
lines.
3-14
Table 3.7 Parameter of Pre-filter
value Effect with IPC-2D
X'00' Linear gamma curve
X'10' Makes low contrast
Image clear (for dark
background document)
Effect with IPC-3D
Linear gamma curve
Default
X'00'