Service manual

CHAPTER 2
2 - 12
COPYRIGHT  2003 CANON INC. CANOSCAN 9900F REV.0 FEB. 2003 PRINTED IN JAPAN (IMPRIME AU JAPON)
III. IMAGE PROCESSING
A. Outline
Image processing system consists of the CCD, analog IC, and ASIC. Analog signal read by the
CCD is converted into digital data, and the digital date is sent to the host computer.
Figure 2-11
B. Image Processing
1. CCD
The CCD is a single chip photoelectric conversion device equipped with several thousand
photosensitive devices. Each photosensitive devices is several microns square, and all devices
are formed into a line to read RGB image signals with a built-in scanning circuit.
CanoScan 9900F uses 6-line CCD.
1) 6-line CCD
6-line CCD has two rows of photosensitive devices in staggered arrangement for RGB each.
This measn that the image with the resolution worth 1600dpi x 2 = 3200dpi can be scanned by
only one scanning operation.
Figure 2-12
To Host Computer
1. CCD
2.. A/D
Conversion
3. Calibration
4. Filter
Processing