Toshiba e-studio550 Service Manual page 106

7. 2. Image Processing Circuit
7. 2. 1. General description
The image of an original placed on the original glass is scanned by the carriage. The CCD (Charge Coupled
Device) reads the optical image signals and converts them into the electrical signal. The electrical signals
then undergo the analog-to-digital conversion and are changed into digital signal. The shading correction
(correction of variance in CCD elements and the light source) is performed on the digital signal, then it is
output as an image signal from the scanning section.
The image processing section receives this image signal from the scanning section and applies various
types of image processing on it, then sends the output result to the writing section.
Images are processed by the SLG board (PWA-F-SLG-340) and PLG board (PWA-F-PLG-340).
(1) Image processing circuit on the SLG board
One image processing ASIC is mounted on the SLG board, realizing the following functions:
<Functions>
High-quality image processing, image memory editing, edit processing, gamma correction,
gradation processing and external output system interface
(2) Image processing circuit on the PLG board
One image processing ASIC is mounted on the PLG board, realizing the following functions:
<Functions>
Smoothing processing, external input system interface, image area control and laser related control
e-STUDIO550/650/810 IMAGE PROCESSING 7 - 2 JUNE 2002 © TOSHIBA TEC