{"657568":{"#nid":"657568","#data":{"type":"news","title":"Terahertz Imaging Reveals Hidden Inscription on Early Modern Funerary Cross ","body":[{"value":"\u003Cp\u003EIn a multidisciplinary project, researchers at the Georgia Institute of Technology and \u003Ca href=\u0022https:\/\/lorraine.gatech.edu\/\u0022\u003EGeorgia Tech-Lorraine\u003C\/a\u003E used terahertz imaging and signal processing techniques to look beneath the corroded surface of a 16\u003Csup\u003Eth\u003C\/sup\u003E-century lead funerary cross. Led by David Citrin, a professor in the \u003Ca href=\u0022https:\/\/www.ece.gatech.edu\/\u0022\u003ESchool of Electrical and Computer Engineering\u003C\/a\u003E (ECE), the effort brought together imaging scientists, a chemist specializing in archaeological objects, and an art historian to reveal a message that had been obscured by time: an inscription of the Lord\u0026rsquo;s Prayer.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;Our approach enabled us to read a text that was hidden beneath corrosion, perhaps for hundreds of years,\u0026rdquo; said Alexandre Locquet, an adjunct professor in ECE and researcher at\u0026nbsp;\u003Ca href=\u0022https:\/\/umi2958.gatech.edu\/\u0022 rel=\u0022noopener noreferrer\u0022 tabindex=\u0022-1\u0022 target=\u0022_blank\u0022 title=\u0022https:\/\/umi2958.gatech.edu\/\u0022\u003EGeorgia Tech-CNRS IRL 2958\u003C\/a\u003E, a joint international research laboratory at the Georgia Tech-Lorraine campus in Metz, France. \u0026ldquo;Clearly, approaches that access such information without damaging the object are of great interest to archaeologists.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe \u003Ca href=\u0022https:\/\/www.nature.com\/articles\/s41598-022-06982-2\u0022\u003Estudy\u003C\/a\u003E was reported March 2 in the journal \u003Cem\u003EScientific Reports\u003C\/em\u003E.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe cross, cut from a sheet of lead, was found in a burial plot at an abbey in Remiremont, France \u0026mdash; a couple hours drive from the Georgia Tech-Lorraine campus. Known as a \u003Cem\u003Ecroix d\u0026rsquo;absolution\u003C\/em\u003E, it is a type of funerary cross that dates to the Middle Ages and has been found at sites in France, Germany, and England.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;This type of cross typically bears inscriptions of prayers or information about the deceased,\u0026rdquo; said Aur\u0026eacute;lien Vacheret, director of the \u003Ca href=\u0022https:\/\/www.remiremont.fr\/culture\/musees-de-remiremont\/musee-charles-de-bruyeres\/\u0022\u003EMus\u0026eacute;e Charles-de-Bruy\u0026egrave;res\u003C\/a\u003E in Remiremont and co-author on the study. \u0026ldquo;It is thought their purpose was to seek a person\u0026rsquo;s absolution from sin, facilitating their passage to heaven.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe museum loaned the cross to Citrin\u0026rsquo;s lab in hopes that the team could use imaging techniques to make the invisible visible. Citrin and his group specialize in non-destructive evaluation and develop techniques that allow for detailed examination of an object\u0026rsquo;s hidden layers without changing or damaging its original form. Although their work often has industrial applications, such as detecting damage to airplane fuselages, the group embraced the opportunity to inspect the cross \u0026ndash; a chance to further explore their technology\u0026rsquo;s applications for archaeological purposes.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EPeeking Beneath the Veil of Corrosion\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe team used a commercial terahertz scanner to examine the cross every 500 microns (about every half a millimeter) across the object. First, the scanner sent short pulses of terahertz electromagnetic radiation \u0026mdash; a form of light that travels on tiny wavelengths \u0026mdash; over each section of the cross. Some waves bounced back from the layer of corrosion, while others penetrated through the corrosion, reflecting from the actual surface of the lead cross. This produced two distinct echoes of the same original pulse.\u003C\/p\u003E\r\n\r\n\u003Cp\u003ENext, the team used an algorithm to process the time delay between the two echoes into a signal with two peaks. This data revealed how thick the corrosion was in each scanned point. The measurements of the light beams that reflected from the underlying metal were then collected to form images of the lead surface below the corrosion.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EInterdisciplinary Insights\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003EAlthough crucial data was gathered during the scanning process, the raw images were too noisy and jumbled and the inscription remained illegible at the time. But Junliang Dong, then a Ph.D. student in Citrin\u0026rsquo;s lab, had the insight to process the images in a special way to eliminate the noise. By subtracting and piecing together parts of the images acquired in different frequencies, Dong was able to restore and enhance the images. What was left was a surprisingly readable image containing the text.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EUsing the processed images, Vacheret was able to identify multiple Latin words and phrases. He determined they were all part of the \u003Cem\u003EPater Noster\u003C\/em\u003E, commonly known as the Our Father or the Lord\u0026rsquo;s Prayer.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe team also worked with a conservationist to chemically reverse the corrosion on the cross, confirming the \u003Cem\u003EPater Noster\u003C\/em\u003E inscription. Comparing their images to the clean cross, the team found their images had revealed parts of the inscription not observable on the original cross. By uncovering additional aspects of the inscriptions that were previously undocumented, their work was able to offer deeper understanding of the cross and further insight into 16\u003Csup\u003Eth\u003C\/sup\u003E-century Christianity in Lorraine, France.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;In this case, we were able to check our work afterwards,\u0026nbsp;but not all lead objects can be treated this way,\u0026rdquo; Citrin said.\u0026nbsp;\u0026ldquo;Some objects are large, some must remain \u003Cem\u003Ein situ\u003C\/em\u003E, and some are just too delicate. We hope our work opens up the study of other lead objects that might also yield secrets lying underneath corrosion.\u0026rdquo;\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003ECitrin\u0026rsquo;s group has also used terahertz imaging to look beneath the surface of 17\u003Csup\u003Eth\u003C\/sup\u003E-century paintings, elucidating paint layer structure and providing insights into techniques of master painters.\u0026nbsp;They are currently investigating surface coatings on ancient Roman ceramics.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe cross project illustrates that success requires more than just accurate measurement, but also careful data processing and collaboration between researchers from disparate fields. The team\u0026rsquo;s approach opens new perspectives for terahertz imaging analysis and could produce great boosts for the fields of digital acquisitions and documentation, as well as character recognition, extraction, and classification.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;Despite three decades of intense development, terahertz imaging is still a rapidly developing field,\u0026rdquo; said Locquet. \u0026ldquo;While others focus on developing the hardware, our efforts concentrate on making the most of the data that is measured.\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003ECitation\u003C\/strong\u003E: Junliang Dong, Ana Ribeiro, Aur\u0026eacute;lien Vacheret, Alexandre Locquet, and D. S. Citrin, \u0026ldquo;Revealing inscriptions obscured by time on an early-modern lead funerary cross using terahertz multispectral imaging,\u0026rdquo; \u003Cem\u003EScientific Reports\u003C\/em\u003E (March 2, 2022).\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EDOI\u003C\/strong\u003E: \u003Ca href=\u0022https:\/\/doi.org\/10.1038\/s41598-022-06982-2\u0022\u003Ehttps:\/\/doi.org\/10.1038\/s41598-022-06982-2\u003C\/a\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EFunding\u003C\/strong\u003E:\u0026nbsp;This work was funded by the \u003Ca href=\u0022https:\/\/www.europe-en-france.gouv.fr\/fr\/fonds-europeens\/fonds-europeen-de-developpement-regional-FEDER\u0022\u003EFonds Europ\u0026eacute;en de D\u0026eacute;veloppement R\u0026eacute;gional (FEDER)\u003C\/a\u003E from\u0026nbsp;the \u003Ca href=\u0022https:\/\/www.grandest.fr\/europe-grandest\/\u0022\u003EConseil R\u0026eacute;gional du Grand Est\u003C\/a\u003E, as well as the \u003Ca href=\u0022https:\/\/www.ic-arts.eu\/\u0022\u003EInstitut Carnot ARTS\u003C\/a\u003E.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EAbout Georgia Tech\u003C\/strong\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe Georgia Institute of Technology, or Georgia Tech, is a top 10 public research university developing leaders who advance technology and improve the human condition. The Institute offers business, computing, design, engineering, liberal arts, and sciences degrees. Its nearly 44,000 students, representing 50 states and 149 countries, study at the main campus in Atlanta, at campuses in France and China, and through distance and online learning. As a leading technological university, Georgia Tech is an engine of economic development for Georgia, the Southeast, and the nation, conducting more than $1 billion in research annually for government, industry, and society.\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Researchers used terahertz imaging and signal processing techniques to look beneath the corroded surface of a 16th-century lead funerary cross, revealing an inscription of the Lord\u0027s Prayer. "}],"uid":"36123","created_gmt":"2022-04-25 18:01:02","changed_gmt":"2022-04-25 19:41:36","author":"Catherine Barzler","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2022-04-25T00:00:00-04:00","iso_date":"2022-04-25T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"657565":{"id":"657565","type":"image","title":"David Citrin Cross","body":null,"created":"1650907960","gmt_created":"2022-04-25 17:32:40","changed":"1650987731","gmt_changed":"2022-04-26 15:42:11","alt":"","file":{"fid":"249219","name":"DSC_0159.JPG","image_path":"\/sites\/default\/files\/images\/DSC_0159.JPG","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/DSC_0159.JPG","mime":"image\/jpeg","size":396460,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/DSC_0159.JPG?itok=UoprwCNV"}},"657567":{"id":"657567","type":"image","title":"Terahertz images of cross inscriptions","body":null,"created":"1650908644","gmt_created":"2022-04-25 17:44:04","changed":"1650911337","gmt_changed":"2022-04-25 18:28:57","alt":"","file":{"fid":"249225","name":"lgsm Figure5-02.png","image_path":"\/sites\/default\/files\/images\/lgsm%20Figure5-02.png","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/lgsm%20Figure5-02.png","mime":"image\/png","size":1745103,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/lgsm%20Figure5-02.png?itok=V4zOz1Sf"}}},"media_ids":["657565","657567"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[],"keywords":[{"id":"187915","name":"go-researchnews"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003ECatherine Barzler, Senior Research Writer\/Editor\u003C\/p\u003E\r\n","format":"limited_html"}],"email":["catherine.barzler@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}