Canon DR-6080, Руководство по обслуживанию

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COPYRIGHT © 2003 CANON ELECTRONICS INC. CANON DR-6080/9080C REV.0 SEPT. 2003
CHAPTER 2 FUNCTIONS & OPERATION
2) Error Diffusion
Error diffusion processing is used to binarize
documents containing gray levels, such as
pictures and photos.
A sample case is shown below, where the
output is set to 4 bits and the slice level is set to 8.
The value of 1 picture element of input image
data is compared with the slice level. When it is
smaller than the slice level, it is output as “0” and
when it is bigger then the slice level, it is output as
“15”.
The difference between the values of the
input and output picture elements is then added
to the next picture element to be processed.
First, when processing the first low of Line 1,
since the data “12” is larger than the slice level
“8”, the output data becomes “15”, and the
resultant error becomes -3(=12-15). (Refer to Fig.
2-512.)
12 9 6 3 1 9 13
Input data
15
Output data
12>8
→
"15"
-3
Error-3=(12-15)
Output
Input
First row of line 1
Fig. 2-512
Next, when processing the second row of
Line 1, since the error is diffused to the right, the
data of the picture element of the second row of
Line 1 becomes “6”(=9-3).
As this value is smaller than the slice level,
the output data is “0” and the error becomes
“+6”[=(9-3)-0]. (Refer to Fig. 2-513.)
The third row of Line 1 and later are
processed similarly.
12 9 6 3 1 9 13
Input data
15
(9-3)=6<8
→
"0"
+6
Error+6=(9-3)-0
Error of first row of Line 1
Input
Second row of line 1
0
Error of first row of Line 1
Output
Output data
Fig. 2-513