Zeiss LSM 880, Operating Manual

Page: 178 / 690

CHAPTER 1 - SYSTEM OPERATION
ZEISS Left Tool Area and Hardware Control Tools LSM 880
172 000000-2071-464 10/2014 V_01
5.2.23.4 How to Optimize Image Quality
As a rule, the first scanned image is not ideal, since
the settings of the laser and therefore also the
photomultiplier might not match the light output.
More often than not, the screen image is dull and
needs subsequent optimization.
•
Use the lookup table Range Indicator (see
section
Dimensions
). This display mode shows
overexposed regions in red and underexposed
regions in blue. Some red and some blue pixels
should be visible to ensure the signal is spread
over the dynamic range of the detector and no
image information is lost.
•
Start a Continuous scan and quickly adjust the
laser power, Gain (Master) and offset to set the
image into the dynamic range.
•
Try to lower the impact of laser light onto the
sample. Reduce the laser power and adjust the
gain accordingly.
•
To adjust the black level (background), use the
Digital Offset
slider so that areas without
picture content just show a trace of blue.
•
If necessary, re-amplify brightness with the
Digital Gain slider.
•
Stop scanning.
•
Save the imaging configuration again as this
time it will also save the correct settings for the
detector, the laser, and the pinhole.
The signal-to-noise ratio can be substantially
improved by reducing the scan speed to an
acceptable level and averaging over several scans
(i.e. with an average
Number greater than 1 for
the
Mean
average
Method
in the
Scan Control
window).
•
Use the
Speed
slider in the
Acquisition Mode
tool set the slowest acceptable scan speed.
•
In the Number text box of the Averaging
panel enter the number of images to be
averaged.
Image optimization can be achieved faster if you select a smaller frame, since less data have to
be processed.
The greater the number of averages selected using
Mean
as average
Method
, the better the
image quality will be; the scan time is prolonged accordingly.
Fig. 254 Image displaying bad adjustment of
gain and offset (blue regions are
underexposed, red regions are
overexposed)
Fig. 255 Image displaying good adjustment
of gain and offset