Digital Image Processing; Outline; Detecting The Orientation Of Originals; Shading Correction - Canon ImageRunner iR8500 Series Service Manual

6.3 Digital Image Processing

6.3.1 Digital Image Processing

iR105i/iR105+ / iR9070
Digital image processing is performed by the reader controller PCB, and it mainly consists of the following:

- shading correction

- auto density correction (AE)
- conversion of 4-channel pixel data to 2-channel pixel data
CCD/AP
PCB

6.3.2 Outline

/ iR8070
Digital image processing is performed by the reader controller PCB, which has the following major functions:
[1] Shading correction
[2] Auto density adjustment (AE)

6.3.3 Detecting the Orientation of Originals

iR105i/iR105+ / iR9070
The orientation of an original placed in the ADF is detected in relation to the direction of the test area of the original by reading text data. On the other
hand, the machine detects the orientation of only the first original, and uses the detected orientation as a reference for changes needed for subsequent pages.
The machine uses the result of detection to determine the following:
- binding margin position
- stapling position
- layout orientation for reduced page composition
Reader controller PCB
J1502
J1107
Gain/offset
correction data
[1]
10bit
[2]
10
[3]
10
[4]
10
[1] 1st-half even-numbered pixel digital image signal
[2] 1st-half odd-numbered pixel digital image signal
[3] 2nd-half even-numbered pixel digital image signal
[4] 2nd-half odd-numbered pixel digital image signal
[5] even-numbered pixel digital image signal
[6] odd-numbered pixel digital image signal
J6002 J5003
Gain/offset
correction data
CCD/AP
PCB
Even-number pixel
digital image signal
8
Odd-number pixel
digital image signal
8
EEP-ROM
CPU
Target value
SRAM
IC
Shading correction
Auto density correction (AE)
Pixel data
conversion from
4-channel-to-2-channel
Dust detection (IC)
F-6-8
Reader controller PCB
Target
CPU
value
Even-number pixel
digital image signal
Shading correction
Odd-number pixel
digital image signal
Auto density
correction (AE)
F-6-9
[5]
Main
8bit
controller
[6]
PCB
8
Original
orientation
detection
PCB
J1901
J1103
EEP-ROM
SRAM
J5004
8
8
Chapter 6
0006-9680
0008-9645
0006-9682
6-5