Canon iR105 Series, Service Manual

Page: 251 / 1029

COPYRIGHT© 2001 CANON INC. 2000 2000 2000 2000 CANON iR105 REV.0 JULY 2001
CHAPTER 3 MAIN CONTROLLER
3-9
2.2 Input Image Processing
Input image data from the reader unit is processed as follows:
2.2.1 Image Data from the Reader Unit
The image signals from the reader unit is subjected to shading correction and turned into
8-bit, 256-gradation intensity signals.
The input is from 2 signal lines: even-bit pixels and odd-bit pixels.
2.2.2 Enlargement/Reduction (main scanning direction)
Image data is processed when it is written into or read from image memory for enlarge-
ment or reduction.
2.2.3 Edge Emphasis
Edge emphasis is performed so that the text, text/photo, print photo, or print photo images
may be made sharp so as to reduce moiré.
2.2.4 Edit Processing
Edit processing is performed to enable the following: blanking/framing, negative/positive
reversal, slant, mirror, fold, repeat.
2.2.5 Density Conversion (LUT)
In this block, intensity signals are converted into density signals; in addition, processing
is also performed so that the output density curve best suited to each mode is obtained.
a. LOG Conversion
Using a LOG conversion table, the intensity signals are converted into toner density sig-
nals in relation to reflected light.
b. Density Adjustment (F-value conversion)
Using an F-value table selected in relation to the setting of the Density key in the control
panel, density adjustment is performed. It, however, will not be performed in memory copy
mode.
c. Density Conversion (
γ
conversion)
Using a
γ
conversion table, density correction is performed for text, text/photo, print
photo, or film photo mode.
2.2.6 Binary Processing (error diffusion method T-BIC)
The error diffusion method (TBIC) is used to control the texture, subjecting data to binary
processing so that it becomes most suited for printing. Specifically, the 8-bit image density
signals of text, text photo, or print photo mode are converted into 1-bit image density sig-
nals (binary).