3. Segmentation

// Input: 3D volume (.tif “image stack”).
   Output: 3D mesh (.obj).

The goal of segmentation is to identify and capture the 3D shape of each of the layers of the rolled papyrus scroll. Each individual surface in our 3D volume that we are able to identify is called a "segment."

We have to do this step both for scrolls and fragments:

• Scrolls. We repeat this process many times for different internal surfaces.

  • Technically we could make one huge "segment" for the entire scroll, but the scroll wraps can be difficult to distinguish in practice, so we split it up into more manageable pieces.

  • Segmentation can be challenging, as different layers of papyrus can be damaged, distorted, or frayed. The carbonized papyrus blisters, and different layers can even fuse with each other.

• Fragments. On fragments this process is a little easier, since they are already fairly flat and have an exposed surface on which we can actually see the ink. Still, the fragments are usually not completely flat, and can have "hidden layers" of papyrus attached underneath the visible layer.