Scan-Graphics CF1000/44, Operation Manual, Page: 35 / 50

2-17
The Tracking Key
The Tracking key toggles the Local Area Adaptive Thresholding mode
(LAT) on or off. The LAT feature determines how thresholds are applied
to detect Binary data. Using LAT increases the amount of binary data
collected, because the threshold level used to detect the data is
automatically adjusted for changes in the local area background density.
Thresholding for Binary Data
Thresholding is an additional form of image processing for binary data. It
is controlled by the Lighter and Darker threshold setting keys in
combination with the Tracking key.
•
When LAT is On, thresholding is dynamic. Dynamic thresholding
takes into account local variations in the density of marks and
background in different parts of the document. In this mode,
thresholds are applied as a percentage of light detected by the
scanner, relative to surrounding document areas. LAT corrects for
variations in the document's background.
•
When LAT is Off, thresholding is absolute. In absolute
thresholding mode, thresholds are applied strictly as a percentage
of light detected by the scanner.
Turn LAT on when the document you wish to scan has varying levels of
image density or its background changes. If the background and image
density are relatively uniform throughout the document, LAT can remain
turned off, as it is in the factory-set default start-up parameters.
1. Press Tracking to turn on LAT.
2. Press Tracking again to turn off LAT.
NOTE: The Tracking key can be switched while the scan is taking place.
LAT can also be toggled on or off through host software, such as
ScanServ, which employs Host Protocol commands. (Thresholding is not
affected by the Filter key settings.)
Tracking