CHAPTER 3 MAIN CONTROLLER
3-9
COPYRIGHT
©
2001 CANON INC. 2000 2000 2000 2000 CANON iR8500/7200 REV.1 AUG. 2001
2.2 Input Image Processing
The image data coming from the reader unit is processed a follows:
2.2.1 Image Data from the Reader Unit
The made signal from the reader unit is subjected to shading correction, and is turned into
an 8-bit, 256-gradation intensity signal.
The signals arrive from two signal lines: one for even-number pixels and the other for
odd-number pixels.
2.2.2 Enlargement/Reduction (main scanning direction)
Image data is processed while it is written to image memory or read from the image
memory.
2.2.3 Edge Emphasis
Edge emphasis is executed to reproduce sharp images while suppressing moire in each
mode: text, text/photo, print photo, film photo.
2.2.4 Editing
In editing, the image data is processed for the following: blanking/trimming, negative/
positive reversal, slant, mirror, fold, repeat.
2.2.5 Density Conversion (LUT)
In this block, the intensity signal is converted into a density signal, and processing is ex-
ecuted so that the best output density curve for each mode may be obtained.
a. LOG Conversion
With reference to the LOG conversion table, the intensity signal based on reflected light is
turned into a destiny signal based on deposited toner.
b. Density Adjustment (F value conversion)
The density is adjusted using the F value table selected to suit the setting of the Density
key on the control penal. However, this is not executed in memory copy mode.
c. Density Correction (γ conversion)
The density is adjusted using the γ conversion table of each mode: text, text/photo, print
photo, film photo.
2.2.6 Binary Processing (error diffusion method; T-BIC)
The error diffusion method (T-BIC) controls the texture by binary processing so that the
image data will be converted into data suited for printing; the 8-bit image density signal in
each mode (text, text photo, print photo) is converted into a 1-bit image density signal (bi-
nary).
To Next Page
Loading...
Need help?
General
