Headwall Photonics Blog

History Made, History Seen with Hyperspectral Imaging

Posted by David Bannon on Mon, Mar 03, 2014

As the market for hyperspectral sensing technology moves forward and advances, Headwall’s Application Engineering team has been able to gather a rare view into the past through the hyperspectral scanning of some of the most important historical artifacts and papers in the United States. For the first time ever, hyperspectral VNIR and SWIR imaging was conducted on key historical documents from the US Civil War period.

The Gettysburg AddressBy working collaboratively with the researchers in the Cornell University Division of Rare and Manuscript Collections and the Cornell Johnson Museum of Art, Janette Wilson and Kwok Wong of Headwall’s Application Engineering team spent a few days conducting VNIR and SWIR hyperspectral scans of some of the most important artifacts held by Cornell University. Of particular interest was the hyperspectral scanning of the University’s collection of original Lincoln documents signed by president Abraham Lincoln during his presidency. This collection included the Gettysburg Address (seen at left), the Emancipation Proclamation, and the 13th Amendment to the Constitution.

The scanning of documents and artifacts with hyperspectral imagers is particularly well suited for the purposes of both 1) research and 2) for establishing a baseline of spectral/spatial information for monitoring change in the artifacts to better preserve objects of cultural heritage.

For a couple main reasons, hyperspectral imaging is particularly appealing to collection-care experts. First, and probably most important, is that the technology is non-destructive. The instruments don't interface with the documents and the lighting is called 'cold illumination.' That is, there is no risk of themal damage to the items under inspection. Second, previously unseen features immediately 'come to light' when viewed hyperspectrally. Note the image below, which represents a stamp on the Gettysburg Address that cannot be seen visibly but can when looked at within the VNIR and SWIR spectral range. Collection-care experts are fascinated by unseen features, which can be used to build the body of knowledge with respect to documents or artifacts.

Unseen Features

Tags: hyperspectral, SWIR, VNIR, Cornell University, artifacts, documents, Gettysburg Address