36 DataMan 300 Quick Reference Guide
DataMan 300 Quick Reference Guide 37
Setting Focus
There is a range of reading distances available for different code sizes
and focus positions. To set focus on your reader, use the following options
depending on whether you use a liquid lens or a manual focus lens.
Liquid Lens
Manual Focus Lens
Focus Feedback (Results Display)
Focus Feedback (Results Display)
Optimize Focus (Focus Settings)
Focus Sweep (Focus Settings)
For setting
Focus Sweep
, follow these guidelines:
• If your application has a consistent reading range, set the focus
range to a limited depth of field with no steps (for example, set it to
20) or with limited steps (for example, set it to 2 steps between 0
and 30). This way you can achieve fast performance.
• If your application has a variety of code types and sizes, set the focus
range to a wider depth of field with increased number of steps (for
example, set it to 6 steps between 0 and 200). This way you can get
better coverage.
Both
Optimize Focus
and the
Focus Feedback
use the same
procedure for testing the current focus. They consider various
subregions of the image.
For maximizing the performance of Optimize Focus and Focus Feedback,
observe the following:
• Use a focus target (such as the one supplied with this Quick
Reference Guide) that includes high-contrast features and is big
enough that it fills at least a 100x100 pixel region in the center of the
field of view at the desired working distance.
•
Make sure the target is perfectly flat (avoid floppy pieces of paper).
• Make sure that the target is perfectly perpendicular to the optical axis
of the reader.
•
Make sure that the rest of the field of view (such as the part not
covered by the focus target) does not contain any high-contrast
features. For example, you would ideally fill the entire field of view
with a white card or sheet of paper (no shadows), then position the
focus target in the middle.
• The supplied focus target (120x120mm) is appropriate for typical
working distances. If you are using a working distance such that the
