The benefit of digitizing coins

All the museums and private collectors in the World possess innumerable coins, either from antiquity or simply dating to the past centuries or so. Until now, each coin had to be recorded and documented by hand – a labor lost.

[Scan of the base color of a coin issued by Konrad, Margrave of Meissen and holder ofthe coinage prerogative, mint date ca. 1150 [Credit: Fraunhofer IFF]

Even the trained eye finds it difficult to immediately recognize the authenticity of a coin. There may be differences in the design according to their provenance but the coins may also be replaced by forgeries after they traveled to outside exhibitions. How can experts be sure that they really receive their original coin back?

Unlike statues, reliefs or paintings, it is impossible to label, mark or barcode the coins. Joint research of the Fraunhofer IFF (Institute for Factory Operation and Automation) in Magdeburg, and the Saxony-Anhalt State Office for Heritage Management and Archaeology, both in Germany; have developed a satisfactory scanning software.

[Coin surface scan [Credit: Fraunhofer IFF]

The new scanner named O.S.C.A.R. (Optical System for Coin Analysis and Recognition) not only scans the features but also records every scratch, pit, denting or other wear, making each scanned object unique. This digitizing of both faces works very much like facial recognition of people, and guaranties an accuracy of at least 98%. The system accepts coins with diameters varying in size between 5 to 75 millimeters, no matter whether they are made of gold, silver, bronze or copper. In just a few seconds, this scanner can determine whether the coin is a full match or has been damaged or replaced by a fake.

To-date, some 10,000 coins from the above mentioned collection have been scanned and the remaining 10,000 will follow soon.

[Combined coin base color and surface scan [Credit: Fraunhofer IFF]

The scanning system works with several cameras and uses several light sources that shine on the coin from different angles, which in turn produces an image with high resolution. The scanner captures more than 1000 visual features for each coin and a reference charts ensures that the images are standardized in comparable color spaces. Numismatists will now be able to recognize both sides of the coins much faster and with higher precision. Eventually the data base can be compared with that of other institution.

Imagine the potential of this facial recognition system! Not only will museums and numismatics from all over the world have access to this system, but they will also be able to place each coin in their true historical context.