Ricoh VT3500, Руководство по обслуживанию

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9.3.3 Main Scan Magnification And Image Shift Processing
[Main Scan Magnification]
Reduction and enlargement in the sub-scanning direction is done by
changing the original transport motor speed (see picture). Reduction and
enlargement in the main scanning direction is handled by the magnification
and image shift processing.
Scanning and plotting are done at fixed intervals (CCD and thermal head
elements’ interval). The image is scanned at the CCD elements’ interval. If
the master is plotted at the same interval (by the thermal head elements)
then the master image is the same size as the original.
[80 % Reduction]
For example, data for 10 pixel elements in a main scanning line are scanned
by the CCD. Those data are compressed into data for 8 pixel elements (data
for imaginary points) by the magnification processor. As a result, the image is
reduced to 80 %.
[140 % Enlargement]
Data for 10 pixel elements of a main scanning line are expanded into data for
14 pixel elements (data for imaginary points). As a result the image is
enlarged at 140 % magnification ratio.
When actual pixel elements are divided in accordance with a magnification
ratio, the value of the imaginary points that would correspond to new pixel
elements are calculated by the magnification processor. The proper value for
each imaginary point is calculated based on the image data of the
surrounding pixels’ values.
1 2 3 4 5 6 7 8 9 10
1" 2" 3" 4" 5" 6" 7" 8" 9" 10" 11" 12" 13"14"
1 2 3 4 5 6 7 8 9 10
1" 2" 3" 4" 5" 6" 7" 8"
11 12 13 14
Scanned Data
Points
Calculated Data
Points
Enlarged Image
Data Points
Scanned Data
Points
Calculated Data
Points
Reduced Image
Data Points
[80% Reduction]
[140% Enlargement]
1 December 1993
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