MegaVision supports
Scientific and Scholarly Publications
When imaging cultural heritage objects, conservators and others express concerns about the illumination levels used, the question can be put simply:
“What are the light levels (of the imaging modality to be used) and how do they compare to museum lighting standards?”
We will provide a response using data from the Leon Levy Digital Dead Sea Scrolls Library
Using multispectral imaging, Reflectance Transformation Imaging (RTI), and photogrammetry to document a 19th century British painting of the Giudecca Canal and Santa Maria della Salute, Venice. The project abstract has been accepted for a poster presentation at the 42nd Annual Meeting of the American Institute for Conservation, May 28-31, 2014, in San Francisco, California.
Team members: Taylor Bennett, Ken Boydston, Jim Wright, Conservator, William Christens-Barry, Ph.D., Equpoise Imaging, LLC, Elisa Stewart, Mike Jennings.
Wilhelm Imaging Research paper titled: “Use of a Multispectral Camera System and Very Small, Comprehensive ‘Micropatch’ Test Targets for Full Tonal Scale Colorimetric Evaluation of the Permanence of Digitally-Printed Color and B&W Photographs” presented at “Imaging Conference JAPAN 2011” in Tokyo on June 7, 2011. The conference was sponsored by The Imaging Society of Japan.
Author: Henry Wilhelm, Ken Boydston, Kabenla Armah, and Barbara C. Stahl
Source: The Imaging Society of Japan
The digitization project of the Dead Sea Scrolls (DSS) was first conceived as yet another conservation effort to preserve the scrolls. The Israel Antiquities Authority (IAA) set out to develop a non-invasive monitoring methodology of their physical state, based on multi-spectral images. Once the IAA realized that they were going to create the best possible images to date and since all of the scrolls have been formally published, they decided to conduct a comprehensive digitization project in addition to developing a monitoring system. The IAA would image all of the DSS, including thousands of fragments, add their metadata, and put everything online, making it available to the public and the scholarly world alike in a way never before imagined.
The digitization project of the Dead Sea Scrolls (DSS) was first conceived as yet another conservation effort to preserve the scrolls. The Israel Antiquities Authority (IAA) set out to develop a non-invasive monitoring methodology of their physical state, based on multi-spectral images. Once the IAA realized that they were going to create the best possible images to date and since all of the scrolls have been formally published, they decided to conduct a comprehensive digitization project in addition to developing a monitoring system. The IAA would image all of the DSS, including thousands of fragments, add their metadata, and put everything online, making it available to the public and the scholarly world alike in a way never before imagined.
https://www.jstor.org/stable/10.5325/jeasmedarcherstu.2.2.0071#metadata_info_tab_contents
G. De Gregorio – E. Gamillscheg – J. Grusková – O. Kresten – G. Martin – B. Mondrain – N. Wilson
To compare agreement between diagnosis of clinical level of diabetic retinopathy (DR) and diabetic macular edema (DME) derived from nonmydriatic fundus images using a digital camera back optimized for low-flash image capture (MegaVision) compared with standard seven-field Early Treatment Diabetic Retinopathy Study (ETDRS) photographs and dilated clinical examination. Subject comfort and image acquisition time were also evaluated. Subjects and methods: In total, 126 eyes from 67 subjects with diabetes underwent Joslin Vision Network nonmydriatic retinal imaging. ETDRS photographs were obtained after pupillary dilation, and fundus examination was performed by a retina specialist. Results: There was near-perfect agreement between MegaVision and ETDRS photographs (κ=0.81, 95% confidence interval [CI] 0.73-0.89) for clinical DR severity levels. Substantial agreement was observed with clinical examination (κ=0.71, 95% CI 0.62-0.80). For DME severity level there was near-perfect agreement with ETDRS photographs (κ=0.92, 95% CI 0.87-0.98) and moderate agreement with clinical examination (κ=0.58, 95% CI 0.46-0.71). The wider MegaVision 45° field led to identification of nonproliferative changes in areas not imaged by the 30° field of ETDRS photos. Field area unique to ETDRS photographs identified proliferative changes not visualized with MegaVision. Mean MegaVision acquisition time was 9:52 min. After imaging, 60% of subjects preferred the MegaVision lower flash settings. Conclusions: When evaluated using a rigorous protocol, images captured using a low-light digital camera compared favorably with ETDRS photography and clinical examination for grading level of DR and DME. Furthermore, these data suggest the importance of more extensive peripheral images and suggest that utilization of wide-field retinal imaging may further improve accuracy of DR assessment.
In 2008, as part of an extensive conservation program, the Israel Antiquities Authority (IAA) announced a project to electronically reimage their entire collection of Dead Sea Scrolls and put the images online. The requirements are high resolution (39 MP) color and near-infrared images and the application of spectral imaging to selected fragments to monitor changes in the Scrolls. The color images capture the current state of the scrolls while the infrared images provide legible text for scholarly use. Spectral imaging will be used to monitor any changes in the parchment reflectance that are known to drive the transition from legible to illegible. This is the major purpose of the IAA Digitization Project. The digitization project will also explore chemical changes of the parchment with Raman and FT-IR spectroscopy. We discuss the decision matrix that led to the final choice of imaging technology: high resolution imaging with monochrome camera and 12 LED wavelengths spanning 435 nm to 940 nm. The visible band images will be converted to RGB color using a mini-color checker in the image field to provide a reference while the 940 nm provides improved legibility for those texts that are illegible to the eye or in color or b/w images. The entire set of wavelength bands will be used for conservation monitoring to look for early signs of changes in the parchment reflectance.
The Library of Congress’ Preservation Research and Testing Division has established an advanced preservation studies scientific program for research and analysis of the diverse range of cultural heritage objects in its collection. Using this system, the Library is currently developing specialized integrated research methodologies for extending preservation analytical capacities through non-destructive hyperspectral imaging of cultural objects. The research program has revealed key information to support preservation specialists, scholars and other institutions. The approach requires close and ongoing collaboration between a range of scientific and cultural heritage personnel – imaging and preservation scientists, art historians, curators, conservators and technology analysts. A research project of the Pierre L’Enfant Plan of Washington DC, 1791 had been undertaken to implement and advance the image analysis capabilities of the imaging system. Innovative imaging options and analysis techniques allow greater processing and analysis capacities to establish the imaging technique as the first initial non-invasive analysis and documentation step in all cultural heritage analyses. Mapping spectral responses, organic and inorganic data, topography semi-microscopic imaging, and creating full spectrum images have greatly extended this capacity from a simple image capture technique. Linking hyperspectral data with other non-destructive analyses has further enhanced the research potential of this image analysis technique.
https://www.spie.org/Publications/Proceedings/Paper/10.1117/12.839000
The Archimedes Palimpsest imaging team has developed a spectral imaging system and associated processing techniques for general use with palimpsests and other artifacts. It includes an illumination system of light-emitting diodes (LEDs) in 13 narrow bands from the near ultraviolet through the near infrared (▵λ≤ 40nm), blue and infrared LEDs at raking angles, high-resolution monochrome and color sensors, a variety of image collection techniques (including spectral imaging of emitted fluorescence), standard metadata records, and image processing algorithms, including pseudocolor color renderings and principal component analysis (PCA). This paper addresses the development and optimization of these techniques for the study of parchment palimpsests and the adaptation of these techniques to allow flexibility for new technologies and processing capabilities. The system has proven useful for extracting text from several palimpsests, including all original manuscripts in the Archimedes Palimpsest, the undertext in a privately owned 9th-century Syriac palimpsest, and in a survey of selected palimpsested leaves at St. Catherine’s Monastery in Egypt. In addition, the system is being used at the U.S. Library of Congress for spectral imaging of historical manuscripts and other documents.
https://www.spie.org/Publications/Proceedings/Paper/10.1117/12.839116
5. Reducing a Challenging Multi-Spectral Imaging Task to Practice
Kenneth Boydston
The multispectral image data set of a cultural heritage object can have a number of uses by disparate parties, and can be in and of itself historically significant. When the object is large, largely degraded, and of significant historical value such as is the late fifteenth-century world map by Henricus Martellus at Yale, acquiring the images that will satisfy known and anticipated demands can be particularly challenging. Time constraints, budget constraints, technological limitations, logistics, handling considerations, risk assessment, personnel, and facilities are among the parameters that can affect the outcome and which should be included in project planning.
Of particular interest are the technological capabilities and limitations. The technology can impact other parameters, and other parameters can impact the technology. While technology will certainly impact the outcome of a multispectral imaging project, it is often the case that technological limitations drive the project—though this should not be the case. In this paper we will suggest that multispectral imaging projects should be driven primarily by the needs of the scholars and conservators who will use the data, and that by focusing on these needs, technological innovations can be created and appropriate technology deployed that will make the difference between mediocrity and success. Examples from the imaging of the Martellus Map demonstrate a few such innovations.
One innovation required by the combination of budget, image spatial resolution, value, size and weight of the object was a large, yet easily portable easel capable of supporting the map and precisely moving both up and down and left and right over a grid of locations. Spatial resolution required that the images be captured in an 11 x 5 grid of tiles and stitched together. Software and hardware protocols were developed to facilitate manual movements of the map. Lasers were integrated to track and maintain focus and camera alignment.
Innovative use of software (MegaVision’s PhotoShoot Multispectral Imaging Capture Software) enabled a capture configuration customized for the particular needs of the map. This configuration was planned in advance, and then modified on site as the nature and needs of the map were revealed in preliminary captured samples. The magnitude of the image data set, together with the complexity of processing software (such as PCA), required innovative methods for preparing the imagery for visual appreciation.
Heyworth, G., Phelps, M., Wisnicki, A., Boydston, K., Easton, R., Van Duzer, C. (2016). Recovering Shared Heritage via Spectral Imaging: Problems, Solutions, Interpretations. In Digital Humanities 2016: Conference Abstracts. Jagiellonian University & Pedagogical University, Kraków, pp. 69-72.
Multispectral imaging is a powerful tool to recover text from manuscripts affected by fading, palimpsesting, water, fire, or overpainting. Many scholars working in the digital humanities have some acquaintance with the technology, but practical experience will help them better understand the range of imaging modalities that comprise contemporary multispectral imaging and the potential of each to advance their research. Though this workshop, scholars will be equipped to identify good candidates for the technology, and thus contribute to the recovery and preservation of our cultural heritage.
The Lazarus Project, headquartered at the University of Mississippi and directed by Gregory Heyworth, operates such a state-of-the-art multispectral imaging system that can be transported to institutions and researchers around the world so that the technology can be made available at no cost. This is part of the educational mission of the Lazarus Project – as a teaching tool for undergraduate and graduate students in the humanities and the imaging sciences – and is the reason why the capability may be offered at no cost. The system has been transported to institutions in the USA, England, Wales, France, Italy, Germany, and the Republic of Georgia to image a number of important historical objects, among which are the Vercelli Book, the Black Book of Carmarthen, and the c. 1491 world map by Henricus Martellus. This mission and capability of the Lazarus Project enables mid-sized institutions with a few manuscripts to benefit from the technology of multispectral imaging without making a sizeable investment in imaging equipment and personnel training. In addition, the cultural heritage objects are imaged at their home institution, without the difficulty of traveling to a stationary system that may be thousands of miles distant. The availability of this portable system that provides multispectral imaging free of charge makes it even more important that scholars who visit libraries and archives be able to identify good candidates for the technology.
The Lazarus Project will offer a workshop for participants in DH2016 in which the portable multispectral imaging system and the subsequent spectral image processing will be demonstrated. These demonstrations will take place in the Jagiellonian Library, and manuscripts from the library will be imaged. Thus, participants in the workshop will have the opportunity to see how multispectral imaging works, from the imaging of the object to the processing of the images and results. Each session will include a description of the equipment and process (camera, lens, LED light system, PhotoShoot software, and processing software tools), a few cycles of imaging of leaves of a manuscript, and a look at what goes into processing the images—with time for questions.
There will be four 90-minute workshops at the following times:
Monday, 11 July 2016: 9:30am – 11:00am
Monday, 11 July 2016: 2:30pm – 4:00pm
Tuesday, 12 July 2016: 9:30am – 11:00am
Tuesday, 12 July 2016: 2:30pm – 4:00pm
A maximum of 17 participants will be permitted in each session due to space constraints in the room in the Jagiellonian Library.
We look forward to seeing you at the demonstration.
Heyworth, G., Van Duzer, C., Boydston, K., Phelps, M., Easton, R. (2016). A Demonstration of Multispectral Imaging. In Digital Humanities 2016: Conference Abstracts. Jagiellonian University & Pedagogical University, Kraków, pp. 929-930.
This paper presents an imaging system that reads texts from books that open less than 30 degrees (due to their fragile bindings) and whose paper quality is degraded. In particular, the system operates on the Scheimpflug principle to correct the geometric distortion necessarily introduced when imaging barely open books. We introduce the guiding principles behind such a system, discuss how it is calibrated and set up, present the results of imaging two dime novels from early twentieth century, both with fragile bindings, and discuss lessons we learned.
Heyworth, Gregory & Knox, Keith & Boydston, Kenneth & Zhu, Yuhao. (2022). Multispectral Scheimpflug: Imaging Degraded Books That Open less Than 30 Degrees. Archiving Conference. 19. 1-4. 10.2352/issn.2168-3204.2022.19.1.1.
Easton, Roger & Sacca, Kevin & Heyworth, Gregory & Boydston, Kenneth & Duzer, Chet & Phelps, Michael. (2015). Rediscovering text in the Yale Martellus map. 1-6. 10.1109/WIFS.2015.7368592.
https://www.researchgate.net/publication/308728959_Rediscovering_text_in_the_Yale_Martellus_map
France, Fenella & Toth, Michael & Christens-Barry, WA & Boydston, K. (2010). Advanced Spectral Imaging for Microanalysis of Cultural Heritage. Microscopy and Microanalysis. 16. 728 – 729. 10.1017/S1431927610054851.
Methods and apparatus enable capture of images of a scene in response to various spectral distributions of light, as well as processing of the captured images to adjust them and, in the case of particular sets of spectral distributions, to derive images accurately representing the colors of the scene.
Kenneth, Boydston., Brian, D., Amrine., William, A., Christens-Barry., Richard, Michael, Colvin. (2011). Multispectral and Colorimetric Imaging System.
https://typeset.io/papers/multispectral-and-colorimetric-imaging-system-47rbv3rq5o
New Light on Old Manuscripts – The Sinai Palimpsests and Other Advances in Palimpsest Studies