When Rutgers Professor Ernst Badian passed in 2011, he left a significant personal numismatic collection to the University.  His collection is a teaching collection and in order to increase access to the collection, the approximately 1258 coins are being photographed and added to the RUCore Fedora Repository hosted at Alexander Library.

http://coins.libraries.rutgers.edu/romancoins/

I originally started working on this project because the coins were being photographed from 7 angles, instead of the traditional 2 angles of obverse and reverse.  You can see an example of the 7 angles here.  https://rucore.libraries.rutgers.edu/rutgers-lib/41098/JPEG/play/#size:800,bgcolor:000000,start:1

The 7 photo process presented some significant difficulties with maintaining depth-of-field and simultaneously obtaining the 3000 pixels necessary for digital preservation standards.  There were a significant number of steps when supporting and lighting the coins during photography that just made the process impractical for the entire collection.

For the time being the photography is limited to obverse and reverse, the traditional method of coin photography.  However, we are still interested in accurately representing the complete coin, and there has been significant progress in the field of 3-D scanning for the purposes of digital preservation.

Rick Hale and I did some experiments using the University’s existing 3-D resources at the Douglass Library.  Librarian Stacey Carton gave us access to a Makerware Scanner and Printer, and while the hardware at Douglass is excellent for design and prototyping, it doesn’t have the resolution necessary for digital preservation.

The Makerbot Digitizer has a X,Y resolution of +-2.0mm, and detail resolution of .5mm.  A structured light scanner can measure subjects using micrometers instead of millimeters, which provides resolution for 3-D models that is much finer than the distinguishing threshold of the human eye.

This paper provides a complete examination of the structured light 3D imaging process (It is all in English once you get past the abstract.)

http://cipa.icomos.org/fileadmin/template/doc/KYOTO/115.pdf

 

Using the guidelines and examples presented by Kampel and company, we are experimenting  with different open source structured light scanning solutions that have been designed with digital preservation in mind.  The  3-D Underworld software from the University of Cyprus is currently the most promising application.  http://www.3dunderworld.org/software/