Canon DR-2580C Service Manual page 50

CHAPTER 2 FUNCTION & OPERATION
c) Advanced Text Enhancement
In this mode, a histogram of brightness
level for each block within the scanned
data is calculated, and an optimum slice
level is determined to binarize the picture
elements.
Binarizing in this way removes the back-
ground, for example, from behind text
printed on a background.
For example, as shown in the image in
Figure 2-516, a histogram for each block
is calculated, and the optimum slice level
is determined to binarize the picture ele-
ments.
Black
Brightness level
Figure 2-516
2-24
6) Automatic Size Detection
Registration
Slice level
White
COPYRIGHT © 2005 CANON ELECTRONICS INC.
In case that the automatic size detection
mode is selected, an image data with the
maximum width and the length detected
by the registration sensors in the feed di-
rection is read.
The maximum outside frame is detected
from the image data which has been read.
The inside of the data is defined as the
document size and the margins are re-
moved.
sensors
Maximum size
Figure 2-517
CANON DR-2580C FIRST EDITION APR. 2005
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