Toshiba 353 Benutzerhandbuch
6
6 - 8
e-STUDIO350/352/353/450/452/453
SCANNER
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6.4 Control of Exposure Lamp
6.4.1 General description
Control crcut for the exposure lamp conssts of the followng three blocks:
(1) Lighting device for the xenon lamp (Inverter)
Control crcut for the exposure lamp conssts of the followng three blocks:
(1) Lighting device for the xenon lamp (Inverter)
Turns ON/OFF the exposure lamp.
(2) CCD circuit
This circuit converts the reflected light amount from the original surface and the shading correc-
tion plate to electrical signals. The exposure amount is controlled in two ways:
tion plate to electrical signals. The exposure amount is controlled in two ways:
(a) White reference formation - reads the reflected light amount from the white shading correction
plate
(b) Black reference formation - reads the light amount at the regulation position with the expo-
sure lamp lights OFF
(3) Image processing circuit
A series of image processes such as a gamma correction and a shading correction are applied
on the output signal from the CCD. The signal is then digitized and output from this circuit.
on the output signal from the CCD. The signal is then digitized and output from this circuit.
PWA-CCD
PWA-SLG
A/D
Fig. 6-401
Original
Shading correction plate
Exposure lamp (xenon lamp)
CCD
Lighting device
for xenon lamp
(Inverter)
Scanner
CPU
Image processing circuit