Image Processing - Canon DR-2580C Service Manual

CHAPTER 2 FUNCTION & OPERATION
V. IMAGE PROCESSING
Note: The principle of the image processing is
described simply in this section so that
you can easily understand it. In actual
cases, the procedure may be somewhat
complicated.
1. Image Processing in Main Body
1) Offset adjustment
Offset adjustment is carried out on analog
signals for the whole image sensor. Black
correction is adjusted so that the minimum
output value of the overall black level
matches the specified value.
2) Gain
adjustment
Gain adjustment is carried out on analog
signals for the whole image sensor. White
correction is adjusted so that the maxi-
mum output value of the overall white
level matches the specified value.
Note: Offset and gain adjustment are used to
perform A/D conversion properly.
3) A/D conversion
This processing converts analog signals
into digital signals. The analog processor
unique to this machine converts analog
signals into 12bit digital signals. However,
12bit data is converted to 8bit data during
the resolution conversion described later.
Note: Shading correction for digital signals is
carried out in a computer, however,
correction values are stored in the flash
memory of the control PCB. The correc-
tion values are output to the computer.
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COPYRIGHT © 2005 CANON ELECTRONICS INC. CANON DR-2580C FIRST EDITION APR. 2005