December 2000 © TOSHIBA TEC
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1600/2000/2500 SCANNER
7.6.2 Shading compensation
The following problems effect the voltage values obtained by photo-voltaic conversion by the CCD:
As a light distribution of light source is varied.
The reflected light is collected by a lens (the light path is shortest at the CCD center and longest
at the ends), there is a difference in the intensities of light reaching the CCD.
The photo-voltaic capacities of each of the 7,450 CCD elements are uneven.
Consequently, these problems must be compensated. This is called “shading compensation.” Shad-
ing compensation involves normalizing optical energy according to the following equation based
on already known scanned black data and white data, and compensating for uneven illuminance
of the image data and device unevenness.
I = k x
where,
k:
Coefficient
S:
Image data before compensation
K:
Black data (in black memory)
W:
White data (in white memory)
(S - K)
(W - K)
Summary of Contents for DP1600
Page 1: ...DIGITALPLAINPAPERCOPIER DP1600 2000 2500 File No 31100011 R0111216600 TTEC ...
Page 2: ...Copyright 2000 TOSHIBA TEC CORPORATION ...
Page 232: ...1600 2000 2500 PCB BOARD 16 2 December 2000 TOSHIBA TEC 16 2 PWA F RLY 16 02 01 ...
Page 233: ...December 2000 TOSHIBA TEC 16 3 1600 2000 2500 PC BOARD 16 3 PWA F PIF 16 03 01 ...
Page 237: ...17 WIRE HARNESS CONNECTION DIAGRAMS 17 1 ...
Page 264: ...1 1 KANDA NISHIKI CHO CHIYODA KU TOKYO 101 8842 JAPAN ...