Filtering And Main Scan Magnification/Reduction - Gestetner A193 Service Manual

2.4.4 Filtering and Main Scan Magnification/Reduction

1. Overview
After auto shading, the image data is processed by both filtering and main
scan magnification. However, to reduce the occurrence of moire in the image,
the processing order is different depending on the reproduction ratio, as
follows.
1) Reduction and Full size
Main Scan Reduction → Filtering
2) Enlargement
Filtering → Main Scan Magnification
2. Filtering
There are two software filters for enhancing the desired image qualities of the
selected original mode: the MTF filter and the smoothing filter.
The MTF filter emphasizes sharpness and is used in Text and Text/Photo
modes. The smoothing filter is used in Photo mode.
The relationships between the coefficient of the filter and the filter strengths
are as follows. Note that these relationships are for copier mode only. Fax
mode has its own unique table. (Refer to the fax section of the service
manual)
The filter strengths for each mode can be adjusted using the service program
mode, SP4-407.
NOTE: Never select "1." Abnormal images may result.
SM 2-11
IMAGE PROCESSING
A193D503.wmf
(A193)