Stereo Scan 440 - DCU

Chapter 2 Operation
2-23
Manual
The signal level can be adjusted using the brightness and contrast controls
assigned to the mouse with the signal level icon. If more than one zone is
displayed, then the detector controlled is the detector assigned to the current zone
(which is indicated by the anchor symbol). The concept of zones will be described
in the Section 2.4.2 Scanning Modes.
Auto Signal Level
The Signal Adjust panel provides the controls for the auto signal level functions.
Brightness and contrast can also be controlled directly from this panel using the
slider bars labelled accordingly.
There are two types of auto signal level function which each operate in two ways.
The auto signal level function will either control the Mean signal level or the
Peak signal level. The mean signal level is defined as being the average
brightness of all the pixels in the image, while the peak level is defined as the
brightness of the brightest part of the image.
Peak and mean signal level controls each operate in two ways. The Find function
is a single shot activation which sets the peak or mean to the level defined in the
associated Auto Video slider bar. The Keep function activates the auto video
function to maintain the video level (peak or mean) of the image at the time of
selection.
Typically the Find function will be used to set the required video level if the
image is a long way from the required brightness. The Keep function is useful
when the content of the image is likely to change, for example if the stage is
being moved across a specimen with distinct light and dark phases, or if the
probe current is being adjusted.
Auto video conttol can be disabled at any time by selecting the Auto Video Off
button.
2.4.2. Using Scan Modes
Before considering the different scan modes available, it is necessary to define
some tenDS which will simplify the whole issue of scan modes, signals and
Windows.
Stereoscan 440 Operator Manual