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Appendix D Settings for Auto-Tracing
AccuScan Settings:
Tolerance
: indicates the precision with which edges are traced.
o
For a detailed bitmap, use a setting of 7 or greater. More nodes will be produced.
o
If the bitmap is of poor quality or has long, smooth edges, then use a setting of 5 or less. A loose
Tolerance will avoid imperfections in the bitmap, though fine details may also be lost.
Corners:
modifies corner recognition and is used to help distinguish parts of the bitmap that represent a
corner, versus parts that represent a tight curve.
o
For angular bitmaps that are composed mostly of sharp corners, use a setting or 7 or greater.
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For bitmaps that are composed mostly of curves use a setting of 4 or less.
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For bitmaps that have a mixture of curves and sharp corners, use a setting of 5 or 6.
Speckle Filter:
Bitmaps that are generated using a scanner often contain speckles, which are usually
caused by a scratched or dirty scanner bed. Also, poor resolution images will often have random speckles
of color that are not to be traced. To ignore these imperfections, the Speckle Filter may be applied as part
of the trace.
Don’t hesitate to increase this value to a high number, especially if
the image doesn’t contain
any tiny details that need to be tarced.
Snap Long Lines to Vertical/Horizontal:
When using a scanner to create a bitmap, the original document
may not be perfectly aligned. As a result, lines that were intended to be precisely horizontal or vertical will
be slightly incorrect. Set the value to the number of degrees that need to be corrected. For example, a
setting of 5 degrees will correct lines that are "off" by that amount. If the Degrees cannot be set high
enough, then the document should be scanned again or the bitmap can be rotated on the workspace.
Small Shape Accuracy:
assess the ratio between the largest bitmap objects versus the smallest.
o
When the ratio appears large, set the accuracy to high (7-10).
o
When objects are similar in size, set the accuracy to low (Off - 3).
Center Line Trace Settings:
Tolerance:
Same as Line Fit Tolerance above, but scale is simply from Loose to Tight
Speckle:
Same as Speckle Filter Factor above, but scale is only from 0 to 4 pixels
Resolution:
As part of the Center Line trace process, the original vector- or bitmap-based object
undergoes rasterization to the set
Resolution
value, and then a trace is performed. The default value of
300 DPI (dots per inch) is adequate for most cases.
Corner Sensitivity
: Same as Line Cornering above but the scale is from 1 to 15.
Detail Level:
The
Detail Level
setting controls Center Line Tracing detail recognition ability.
o
If a bitmap contains a lot of detail, set the
Detail Level
to a higher value.
o
If it a simple image, set the
Detail Level
lower.
o
Moderate settings work best with images that include areas of high detail with areas of low detail.
Truncate Endpoints
The
Truncate Endpoints
setting controls the Center Line Tracing corner and
endpoint recognition ability. Center Line Tracing uses this setting to determine which parts of a trace
represent a corner/endpoint, and which parts represent a tight curve.
o
If a bitmap contains sharp corners, and is mostly angular with sharp endpoints, set to a lower value.
o
If it is mostly curves, set to a higher value.
