Image Processing; Overview - Gestetner A193 Service Manual

2. IMAGE PROCESSING

2.1 OVERVIEW

D r u m
LDDR
LDDR: Laser Diiode Driver
BICU: Base Engine & Image
Controller Unit.
SBU: Sensor Board Unit
IPU: Image Processing Unit
The CCD (Charged Couple Device) 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 into the BICU (Base-engine and Image Control
Unit) board.
The BICU board can be divided into three image processing blocks; the IPU
(Image Processing Unit), FCI (Fine Character Image), and LD controller
GAVD (Gate Array Video Drive)
IPU: Auto shading, filtering, magnification, γ correction, and gradation
•
processing
•
FCI: Smoothing (binary picture processing mode only)
•
LD controller: LD print timing control and laser power PWM (Pulse Width
Modulation) control
On completion, the BICU board sends the video data to the LD drive board at
the proper exposure time.
SM
L D
Controller
LD Driver
( G A V D )
BICU
R
F a x
Controller
2-5
IMAGE PROCESSING
SBU
T
I P U
FCI
X
Fax Controller
X
M S U
Printer
Controller
A193D501.wmf
(A193)