Virtualization Process Overview
How does IVL staff virtualize an object? We use a seven step process which is relatively simple even if the technology used to do it is not.
Step One – All the data available on the object being scanned is compiled for inclusion in the database we have constructed for IVL Virtual Specimen Library. This information can come from collections data, individuals, publications, and other sources.
Step Two - The object is scanned using either IVL laser surface scanners or a computed tomography (CT) device which passes a three-dimensional X-ray through the object slice by slice. For the former, multiple scans are conducted to capture the whole object and these are merged to produce a virtual model. With CT work, a series of slices through the object are assembled into a solid virtual model. In both processes, each scan or slice must be viewed and edited to remove spurious data points – the scanning process is far from perfect.
Step Three - Once either of the above scans has been completed, the virtual model consists of a “cloud” of data points, called point clouds, which describe the outside surface of the object. With the CT scanning process, the interior structure of the object is represented by point clouds as well.
Step Four – The point clouds are then automatically connected with a network of triangles or polygons, a process called polygonalization. The polygons are somewhat similar to facets on a diamond.
Step Five - The defined, polygonized surfaces are then “rendered” to produce a solid-looking virtual model. The rendering process analyzes the reflectivity, color, and other characteristics of the scanned object. During this step, a source of light which creates shadows on the model is also defined.
Step Six - With surface-scanned objects, we next photograph the original specimen from many angles using a high-resolution digital camera.
Step Seven – Finally, these photographs are “wrapped” around the point clouds (a process called Texture Mapping) which gives the final virtual model its incredibly realistic appearance.