Konica Minolta BizHub C360 Service Manual page 284

Theory of Operation Ver. 1.0 Jul. 2009
• The following detail the image processing operations performed by MFP board on the
Write section.
1. Correct variations in reading caused by pixel-to-pixel variations in sensitivity of the
CCD sensor and uneven light distribution by the exposure lamp. A peak-hold-type
shading correction is performed, in which the maximum value of two or more read-
ings of two or more lines is taken to prevent effect due to dust or dirt on the shading
sheet.
2. To correct differences in the position of each chip of CCD sensors R, G, and B,
FIFO memory is adopted to match the output timing. Also correct color aberration
of the lens.
3. The security pattern created during printing on this machine is detected and copy-
ing is enabled or disabled through a password (when the security kit SC-507 is
mounted).
4. If outer document elimination is selected from the control panel, document area
determination processing is performed for each line within the document area data
acquired during prescan. Then, the START and END positions of the document
area in the main scanning direction are detected and the area outside the START
and END positions is erased as the outside-the-document area.
5. The scanning area is divided into multiple blocks. The ratio of color or monochrome
is calculated for each of these blocks. The machine then determines whether the
entire original is colored or monochrome.
6. A histogram of lightness for AE processing is generated. The AE level of the docu-
ment is determined based on this histogram and AE processing is performed.
7. R, G, and B data are then converted to value and color component data for adjust-
ments of saturation, lightness, and hue.
8. Each image area, whether it is a color edge area, black edge area, dot area, or a
continuous gradation area, is discriminated.
9. Other types of processing performed are the improved reproduction of black text,
edge emphasis, smoothing and color balance.
10. Each Image data of R, G, and B is compressed to reduce the consumption of data
capacity.
11. Temporarily storeds The BTC-compressed image data.
12. The stored image data is compressed in the JBIG (Joint bi-level image experts
group) format.
13. Each Image data of R, G, and B in the copy, print, scan, and fax mode is stored. In
PS printing, multi-valued data of Y, M, C, and K is stored.
14. The image data read from the file memory is uncompressed through a method in a
reverse way of JBIG compression. At this time, image rotating or sorting processing
is conducted.
15. JBIG image data are expanded in the frame memory.
16. Each Image data of R, G, and B is stored in frame memory.
17. Temporarily stores the image data output from the frame memory.
18. The image data is expanded through a method opposite to that used in the BTC
compression.
19. FIFO memory is used to enlarge or reduce images in the main scanning direction.
The image is enlarged by increasing the number of data readings and reduced by
decreasing the number of data readings.
20. Reduction processing is conducted in sub scanning direction. No processing is
done at same size or zoom, but at reduction, the lines are thinned out.
24. IMAGE PROCESSING
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