Gestetner A294, Service Manual

Page: 67 / 600

IMAGE PROCESSING
SM 2-17 A294/A295
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2.3 IMAGE PROCESSING
2.3.1 OVERVIEW
The CCD generates an analog video signal. The SBU (Sensor Board Unit)
converts the analog signal to an 8-bit digital signal, then it sends the digital signal
to the SICU (Scanner and Image Processing Control Unit) board.
The SICU board can be divided into two image processing blocks: the IPU (Image
Processing Unit) and the MSU (Memory Supercharger Unit). These two ICs mainly
do the following:
•
IPU: Auto shading, filtering, magnification,
γ
correction, gradation
processing, and video path control
•
MSU: Image compression, image rotation, interface with HDD controller,
image repeat, and combine originals
Finally, the SICU board sends the video data to the laser diode array (LDA) on the
LD drive board (LDB).
SBU
CCD
P W M
D r u m
SICU
L D
Controller
( G A V D )
IPU M S U
H D D 2
H D D 1
L D B
P W M
P W M
P W M
L D D
L D D
L D D
L D D
L D A
A294D578.WMF
CÓPIA NÃO CONTROLADA
CÓPIA NÃO CONTROLADA