3.5.3Selecting Scanning Speed
Eight scanning speeds are available with four buttons.
To select a scanning speed, click one of the Scan speed icons 
on the control panel.
Two scanning speeds are assigned to each button. They are set alternately by clicking the button. Totally 14 scanning speeds are available for image observation. The assignment of scanning speeds to four buttons can be customized. Refer to <2.3.5.3 Scan Control block>
The Run/Freeze 
(
) button on the Scanning Image window changes run (irradiate
and scan electron beam on the specimen, and continuously acquire image) and freeze (blank electron beam and stop image acquisition ) status alternately. While electron beam is scanning, the string “RUN” is blinking at the
(1) TV Scanning: 
TV Scanning of
Two Fast Scanning speeds, TV1 and TV2, operate at the same speed but allow different number of frames to be averaged for each are available.
To set the number of frames to be averaged, use the Image tab in the Setup dialog window. In the FAST SCAN AVERAGING area, set TV1 and TV2 value. Recommended numbers are 4 for TV1 and 8 or 16 for TV2. The higher the number of frames, the better the attainable image quality.
The TV scanning runs with 640x480 pixels only. When used in full screen mode, the image size is reduced to half.
(2) Fast Scanning: 
Fast Scanning runs with a half speed of TV scanning. It is also convenient for a field search of the specimen, coarse focus, etc.
The full size image is displayed when used in full screen mode. The quality (S/N ratio) of the image is improved by frame averaging.
Two Fast Scanning speeds, FAST1 and FAST2, operate at the same speed but allow different number of frames to be averaged for each are available. To set the number of frames to be averaged, use the Image tab in the Setup dialog window. In the FAST SCAN AVERAGING area, set TV1 and TV2 value. Recommended numbers are 2 or 4 for FAST 1 and 4 or 8 for FAST 2.
(3) Slow Scanning: 
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