Canon Vizcam 1000, Service Manual

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3. OPERATION AND TIMING
COPYRIGHT © 2001 CANON INC. CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
3-46
REF.
1. Xmin ..... Stores the coordinate where black changes to white first.
2. Xmax .... Stores the coordinate where white changes to black last.
3. Ymin ..... Stores the coordinates nearest the start of the main scanning line where black
changes to white.
4. Ymax .... Stores the coordinates farthest from the start of the main scanning line where
white changes to black.
The position and the size of an original are automatically identified to enable automatic ratio selection,
automatic paper selection, and image shifts.
If the RF is installed and an original is placed on the copyboard, original position identification
cannot be executed.
d. Mirror Image Processing
Figure 3-316
e. Input Masking
When light reflected by an original is
separated into three colors by color separation
filters (RGB), it would be ideal if each filter let
through light of a specific range of wavelengths
and blocked out light of other wavelengths.
a b c
a b c
< Original >
Main scanning direction
< Copy >
Sub scanning direction
Principle
When reading data from the RAM for a single
scan, reading is executed in reverse to create a
mirror image in relation to the main scanning
direction.
Figure 3-317
Figure 3-318
12345678..
Address
-2-1
...nnn
1 pixel (1 byte)
Writing Reading
Image signal
Degree of transmission by filter
Wavelength (nm)
500 400 600 700
100%
B G R