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Wednesday, May 31 • 3:30pm - 4:00pm
057. (Research and Technical Studies) Improvements in 2D x-radiography and volumetric x-ray tomosynthesis

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Use of x-ray imaging permeates the process of art and artifact care and conservation. As with any technology–based tool, advances in hardware and software capabilities bring about refinement and expansion in existing areas as well as enabling new areas of application. For instance, there are two main methods of radiography, Computed Radiography (CR) and Digital Radiography (DR). Each method has practical advantages and limitations. One limitation of DR has been that conventional DR plates have not been sensitive to x-ray energies below 40kVp. By incorporating new carbon fiber tops and locating low-noise electronics away from the detection region, the detection threshold can be lowered to ~15kVp. The improvement in low energy detection allows us to present 2D x-ray images taken with a DR plate of laid lines, legible text and watermarks on paper, colorants on maps, as well as changes in wood grain density and weave configurations of cloth. Possessing 3-dimensional knowledge of the condition and construction of an object can provide the conservator with interesting and even essential information. We will describe a newly available volumetric x-ray tomosynthesis technique that uses a series of 2D radiographs taken from different perspectives varying two degrees of angular freedom. Each radiograph contains the entire volume to be examined so no interpolation between slices is necessary as in computed axial tomography. The volume reconstruction software requires that configuration details for each input image be known. Consequently, highly accurate and precise measurements of image features can be made easily. We have used the technology with a variety of sources and DR plates and have recently employed CR systems commonly found at museums and non-destructive testing laboratories. Because of the relatively small amount of data gathered, the user can scroll the focal plane through an object along any axis in near real time with just a typical laptop computer. The hardware is portable so that exams can be made within an x-ray vault, out on the museum floor or in the field. The software output in the form of image stacks interfaces readily with 3D printing and virtual reality technologies. At last year's AIC conference, we showed how this volumetric technique could be applied in examining the paint layers of paintings on wood or canvas while suppressing contributions to the view caused by supporting understructures in the form of cribbing or stretcher bars. Input images of paper with double-sided print can now be examined by volumetric tomosynthesis by capitalizing on the improvements in the DR plates described above. We will show that text can be read and paper thickness measured by setting the focal plane to each of the two sides of the paper. These achievements are possible even when the paper is placed within an envelope.

Speaker(s)
avatar for Dr. Dan Boye

Dr. Dan Boye

Professor of Physics, Davidson College
Dr. Dan Boye, Professor of Physics at Davidson College, has almost 30 years experience in physics research and education. Fundamental research areas include optical properties of insulating crystals, glasses and nano-materials doped with rare earth and transition metal ions, energy... Read More →


Wednesday May 31, 2017 3:30pm - 4:00pm
Riverside West Exhibit Hall Exhibit Level, East Tower

Attendees (24)