Canon iR2030, Руководство по обслуживанию

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Chapter 4
4-16
Functions of the image processing system are summarized below.
T-4-10
The reader controller PCB is used to process images on a line-by-line basis. Its major functions are as follows:
1)Analog image processing
- CMOS sensor drive
- CMOS sensor output gain correction and offset correction
- CMOS sensor output A/D conversion
2)Digital image processing
- Shading correction
F-4-30
4.3.6.2 CMOS Sensor Drive
0017-2637
iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018i
The CMOS sensor used in this machine is a 1-line linear image sensor consisting of 7488 photocells. After completion of photoelectric conversion in the light-
receiving block, the signals are output to the AP circuit in the reader controller PCB in parallel for each channel (total four channels) of the CMOS sensor array.
F-4-31
4.3.6.3 CMOS Sensor Output Gain Correction and Offset Correction
0017-2638
iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018i
The analog video signals output from the CMOS sensor are corrected so that they will have a specific gain level (gain correction), and the output voltages generated
in the absence of incident light are also corrected so that they it will have a specific offset level (offset correction).
4.3.6.4 CMOS Sensor Output A/D Conversion
0017-2639
iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018i
After completion of the above corrections, the analog video signals are converted to digital signals corresponding to individual pixel voltage levels by the A/D
converter.
4.3.6.5 Shading Correction (Outline)
0017-2640
iR2022i / iR2025 / iR2030 / iR2018 / iR2022 / iR2018i
- Reader controller PCB CMOS sensor drive, analog image processing, A/D
conversion, and shading correction
Target
value
CMOS sensor (1 line)
Analog image signal
Analog image
processing
- Gain correction
- Offset correction
A/D
conversion
CMOS sensor
drive control
CMOS sensor
control signal
Gain
correction
data
Digital
image
signal
IC1
10
Digital image
signal
8
Reader controller PCB
Contact image sensor (CIS)
J309
RAM
Shading correction
IC2
Serial
communication
I/F
CMOS sensor 1 CMOS sensor 4 CMOS sensor 3
H L L H H L H L H H L
output
Light receiving block