|This image shows a well-aligned model. Notice the clarity of incisions, presence of fine detail and a general clean appearance. This model can be trusted to examine fine detail of the fragment, such as guidelines.|
|As the fragments get larger,
errors in alignment create blurring artifacts. Notice that the fragment
has an overly smooth appearance, the incisions are not clear, and some
incisions have artificial double lines.
|Although you cannot trust the
fine details on this fragment, such as depth of incisions, the models
are still useful for looking at large-scale features such as clampholes
and overall incision patterns.
|In the cases where the complete
models are overly blurry, we provide a finer resolution model of just
the top of the fragment. This model should be used solely for close up
examination of the fragment's incisions.
|Another artifact arising from
bad alignment is noise in the models. This has the appearance of bumps
and craters of various sizes on the surface of the model, and in particular along
any sharp edges. Notice the bumpy appearance of the fragment on the
|Closeup of the right edge of the
model shows the characteristic "bumps" that are due to noisy scans.
These bumps are not part of the original fragment.
|Here is another examination of noisy
misalignment artifacts. Notice a bump along the edge of the fragment
and the sprinkling of extrusions from the surface. A similar bump along the
edge is sometimes present even in well-aligned models, where it is due
to edge curl in the vripping process
|When the surfaces that are being
scanned are too dark or occluded, the laser scanner does not return any
data. As a result you may encounter holes in our models.
|To make our models more visually
pleasing, we have filled the smaller holes with an artificial surface
using an automated process. Most of the time, this holefilling is
unnoticeable to the user and does not create any false impressions about
the original fragment, since the artificial surface follows the
geometry of the model. However, when a particularly large hole is
filled, a smooth piece of surface is created that may be very different
from the original fragment. The image on the left shows a hole from an
iron bar filled with a smooth surface. These artifacts are particularly
easy to spot and ignore since the holefilling surface is a lot smoother
than the geometry that surrounds it.