Input Image Processing; Image Data From The Reader Unit; Enlargement/Reduction; Edge Emphasis - Canon iR2200 Service Manual

CHAPTER 2 MAIN CONTROLLER

2.2 Input Image Processing

The image data from the reader unit is processed for the following:

2.2.1 Image Data from the Reader Unit

The image signals from the reader unit are 8-bit, 256-gradation intensity image signals
which have been subjected to shading correction.
The signals arrive from two signal lines (for even- and odd-numbered pixels).
2.2.2 Enlargement/Reduction (main scanning direction)
An image is enlarged or reduced by processing image data when writing it into or reading
it from image memory.

2.2.3 Edge Emphasis

For each mode (text, text/photo, print photo, film photo), edge emphasis is executed so as
to increase sharpness while suppressing moire.

2.2.4 Editing

The machine provides various editing functions: negative/positive reversal, mirror, fold.

2.2.5 Density Conversion (LUT)

In this block, the intensity image signals are converted into density image signals, and
processing is executed so as to enable the best output density curve for a specific mode in
question.
a. LOG Conversion
Using a LOG conversion table, intensity image signals based on reflected light are con-
verted into density image signals based on density data.
b. Density Adjustment (F-value conversion)
The F-value table most suited to the setting of the Density key in the control panel is used
to adjust the density; it, however, will not be executed in memory copy mode.
c. Density Correction (γ γ γ γ γ conversion)
The γ conversion table best suited to each specific mode (test, text/photo, print photo, film
photo) is used to correct density.
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COPYRIGHT © 2001 CANON INC. 2000 2000 2000 2000 CANON iR2200/iR2800/iR3300 REV.0 MAR. 2001