Service manual

IMAGE PROCESSING March 2006
6-8
6.5 IMAGE PROCESSING
6.5.1 IMAGE PROCESSING FLOW
Image processing is done by the IPU (Image Processing Unit) on the MPU board,
following the steps shown below.
Shading Correction
↓
Reduce/Enlarge
↓
Filtering
↓
Gamma Correction
↓
Grayscale Processing
Shading Correction:
Corrects errors in the signal level for each pixel using the white plate.
Reduce / Enlarge:
Reduces or enlarges the image in the main-scan direction by data processing.
(Image magnification in the sub-scan direction is controlled by changing the
scanning speed.)
Filtering:
Improves the scanned image data, to make the image as close to the original as
possible.
Gamma Correction:
Background erase
Grayscale Processing:
Compares each pixel with surrounding pixels to enhance the image.
• Text mode: Binary processing
• Photo mode: Error diffusion