December 2002 TOSHIBA TEC 6 - 7 e-STUDIO160/200/250 IMAGE PROCESSING
6.4 Scanner
Light reflected from the original surface is picked up by the CCD (Charge Coupled Device) where photo-
voltaic conversion is carried out. By photo-voltaic conversion, optical image data are converted to electri-
cal signals. These analog electrical signals are then converted to digital signals by A/D conversion, and
the required image processing is carried out on these digital signals.
(1) Photo-voltaic conversion
Optical signals from the original are converted to electrical signals by the CCD device. For details, see
Chapter 7, 6-1.
(2) Signal amplification
After conversion by the CCD, the electrical signals are amplified.
(3) A/D conversion
Analog signals are converted to digital signals.
(4) Shading correction
The signals picked up by the CCD device are compensated. For details, see Chapter 7, 6-2.
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CCD
Signal
amplification
A/D
conversion
Shading
compensation
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