Half Tone Density Processing; Binarisation - Canon GP160DF Service Manual

F.

Half tone density processing

The half tone density processing correction curve changes depending on the follow-
ing:
• The copy density setting on the control panel
• The scanning mode (character, character/photo, photo)
In accordance with the copy density setting on the control panel, there is either a
light image or a dark image curve as shown in Figure 4-307.
Furthermore, when photo mode is selected in the scanning mode, the gradation
characteristics are good, and the curve faithfully reproduces the document's density as
shown in Figure 4-308.
Copy density
Dark
image
Figure 4-307
G.

Binarisation

After the half tone processing has finished, multi-value data are converted into bina-
ry data.
The binarisation technique which the unit uses employs is the error diffusion system.
The data which have been binarised are sent to the DC controller PCB with a
recording resolution of 1200 x 600pdi equivalent.
COPYRIGHT © 1999 CANON INC.
Light
image
Character
mode
Document density
CANON GP160 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 4 IMAGE PROCESSING SYSTEM
Copy density
Character
mode
Figure 4-308
Character /
photo mode
and photo
mode
Document density
4-9