Binary Processing; Dither Screen Method - Canon GP605 Service Manual

G.

Binary Processing

The copier performs binary processing for the following:
[1] Print photo mode (dither screen method)
[2] Text, text/photo mode, print photo mode (R-ED, i.e., random error diffusion, method)
1.

Dither Screen Method

Image data is subjected to screen processing so that the images may be produced in 256 grada-
tions out of binary data.
4 pixels
In this area, as many as 16
different density patterns
may be created. As such, an
area consisting of 8 × 4
pixels enables creating of
256 (16 × 16) density
patterns.
Figure 4-305A Conceptual Diagram of the Dither Screen Method
COPYRIGHT © 1999 CANON INC.
The black pixels are
thickened according to
density.
CANON GP605/605V REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 4 IMAGE PROCESSING SYSTEM
Screens consisting of 106
lines running at 45˚ are
created.
4-15