Service manual

CHAPTER 2
2 - 16
COPYRIGHT  2003 CANON INC. CANOSCAN 9900F REV.0 FEB. 2003 PRINTED IN JAPAN (IMPRIME AU JAPON)
2) Averaging
When scanning at lower resolution, the quality of output tends to be deteriorated. This is
because data thining occures more frequently at lower resolution. Averaging is a process to
average the data to be thinned and the data to be actually output to prevent the image
deterioration.
Figure 2-16
ABCD
EFGH
ABCD
EFGH
A
BCD
EFGH
A'
E'
CCD
reading
data
Output
image
data
Thinned data
CCD
reading
data
Output
image
data
Averaged data=(A+B+C+D)/4