Datalogic DS8100A, Справочное руководство, Страница: 95 / 141

READING FEATURES
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9 READING FEATURES
9.1 ADVANCED CODE RECONS
TRUCTION (ACR™ 4)
The traditional way of barcode reading could be called “Linear Reading”. In this case, the
laser beam crosses the barcode symbol from its beginning to its end as shown in the
following figure:
Laser Beam
Figure 90
– Linear Reading
In Advanced Code Reconstruction mode it is no longer necessary for the laser beam to cross
the label from the start to the end. With just a set of partial scans on the label (obtained using
the motion of the label itself), the DS8100A is able to “reconstruct” the barcode. A typical set
of partial scans is shown in the figure below:
Code Direction
Figure 91
– Partial Scans
None of the partial scans contains the whole label. The decoder aligns each partial scan
correctly and combines them in order to obtain the entire code.
The alignment is performed by calculating the time difference from one partial scan to
another using a reference code element.
9.1.1 Tilt Angle for Advanced Code Reconstruction
The most important parameter in Advanced Code Reconstruction is the value of the
maximum tilt angle ( maximum) under which the code reconstruction process is still
possible.
Laser Beam
= tilt angle
0° to max
Figure 92
– Tilt Angle