Toshiba e-STUDIO 550, Service Manual

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e-STUDIO550/650/810 IMAGE PROCESSING 7 - 4 JUNE 2002 © TOSHIBA TEC
7. 3. SLG Board (PWA-F-SLG-340)
7. 3. 1. Features
(1) The image processing ASIC on the SLG board is controlled by the CPU on the SLG board.
(2) The image processing ASIC on the SLG board realizes the following functions:
• High-quality image processing
• Image memory editing
• Editing processing
• Gamma correction
• Gradation processing
• External output system interface
7. 3. 2. Functions of image processing circuit
An image processing ASIC mounted on the SLG board realizes the following functions:
(1) High-quality image processing
(a) Range correction
This function corrects the density range of the image signals, and adjusts it so that it is suited to each
original image. It is possible to eliminate undesirable background density when an original with a certain
level of density on the background, for example a newspaper, is copied.
<Example>
Histogram
Dynamic range
Small
No. of pixels
Large
Low
Density
High Low
Density
High
Text
Back-
ground
After range
correction
Extended dynamic range
Small
No. of pixels
Large