Toshiba e-STUDIO281c Service Manual page 176

The above averaging operation is performed for all the pixels to accomplish the high reproducibil-
ity of original.
(The following is the case that the low pass filtering is applied on the primary scanning pixel.)
Density
0 1 2 3 4 5 6 7 8 9
Primary scanning pixel positions
High-pass filter processing
Character outline blurs when the original, such as text, with big difference in density among the
pixels is optically scanned and output from the CCD. Characteristic of the lens and other factors
cause this phenomenon. In this equipment, processing such as edge enhancement is applied
between the targeted pixel and the neighboring pixels to eliminate this phenomenon and realize
high reproducibility of original.
5) Image memory editing
This function performs editing such as enlargement/reduction, mirror imaging, etc., by using a line
memory. Pixel data for one line in the primary scanning direction is stored in the line memory and
the memory is renewed at each line.
- Enlargement/Reduction
Enlargment/Reduction is accomplished by using the line memory control function in the process
of the image processing operation.
<Example> Enlargement
e-STUDIO281c/351c/451c IMAGE PROCESSING
After low-pass filter
Fig.7-5
Solid black area
Original
Image signal
After correction
Fig.7-6
100%
1 2 3 4
200%
1 1 2 2
7 - 6
Density
0 1 2 3 4 5 6 7 8 9
Primary scanning pixel positions
Low contrast area
5 6 7 8 9 10
3 3 4 4 5 5
June 2005 © TOSHIBA TEC