Thinking Outside the Color Profiling Capture Box

Color-capture systems use color-correction processing operations to deliver expected results in the saved image files. For cultural heritage imaging projects, establishing and monitoring such operations are important when meeting imaging requirements and guidelines. To reduce unwanted variations, it is common to evaluate imaging performance, and adjust hardware and software settings. In most cases these include the use of ICC Color profiling software and supporting measurements. While advice on the subject by experts can be deftly persuasive, discussions of color goodness for capture are clouded by many imaging variables. This makes claims of a single, color-profiling approach or engine moot in the context of a greater workflow environment. We suggest looking outward and considering alternative profiling practices and evaluation methods that could improve color image capture accuracy and consistency.

A practitioner’s guide to fringe projection profilometry

Many techniques exist for 3D digitization of cultural heritage objects. Paintings, manuscripts, and other near-planar objects are especially challenging to digitize because of their minute surface variations. Of the existing techniques, fringe projection profilometry (FPP) is one of the most promising approaches for measuring the surface shape of such objects. In practical implementations of FPP, one needs to understand and control various sources of error due to system hardware and environmental conditions. It is difficult to find information on this in one place in the literature, which discourages application of the technique. In this paper we present a practitioner’s guide to phase-shifting fringe projection profilometry that covers critical but often omitted implementation details required for successful application of the technique.

Digital Archiving of Civil War Graffiti for Research & Access

Historic properties face challenges preserving and maintaining their physical heritage, as well as digitally sharing and accessing their history in a virtual environment. They are now utilizing new advanced imaging methods to research their cultural heritage artifacts. Recent advanced imaging in historic Civil War-era houses demonstrated the integration of imaging techniques and data to support conservation of these structures and research into their history and contents. New technical systems, including the latest narrowband multispectral imaging systems and higher resolution cameras, raise major challenges in not only the integration of new technologies, but also the ability to store, manage and access large amounts of data. Integration, preservation, access and collaboration with the image data from this program requires implementation of standardized digitization and data archiving practices.

Color Accuracy-Guided Data Reduction for Practical LED-based Multispectral Imaging

The color accuracy of an LED-based multispectral imaging strategy has been evaluated with respect to the number of spectral bands used to build a color profile and render the final image. Images were captured under select illumination conditions provided by 10-channel LED light sources. First, the imaging system was characterized in its full 10-band capacity, in which an image was captured under illumination by each of the 10 LEDs in turn, and the full set used to derive a system profile. Then, the system was characterized in increasingly reduced capacities, obtained by reducing the number of bands in two ways. In one approach, image bands were systematically removed from the full 10-band set. In the other, images were captured under illumination by groups of several of the LEDs at once. For both approaches, the system was characterized using different combinations of image bands until the optimal set, giving the highest color accuracy, was determined when a total of only 9, 8, 7, or 6 bands was used to derive the profile. The results indicate that color accuracy is nearly equivalent when rendering images based on the optimal combination of anywhere from 6 to 10 spectral bands, and is maintained at a higher level than that of conventional RGB imaging. This information is a first step toward informing the development of practical LED-based multispectral imaging strategies that make spectral image capture simpler and more efficient for heritage digitization workflows.

Layering Historical Maps and Census Data for Interactive Visualizations in HistoryForge

HistoryForge (<ext-link ext-link-type="uri" xlink:href="https://historyforge.net">https://historyforge.net</ext-link>) is a web application that combines information from U.S. Census records, historical maps, and other records in an interactive framework of human and spatial relationships that illustrate what communities looked like and how they evolved over time. It generates an environment that invites a study of local history at the levels of neighborhood, family, and individual. HistoryForge is being developed using open source software so that any community can adopt it to explore their own local history and add archival material. This paper will describe the project's development, growing potential for enriching records with archival material, and its current implementation in four different communities. The rapid development of the last year has been supported by a two-year grant from the Public Engagement with Historical Records from the National Historical Publications and Records Commission of the National Archives.

EN 17650 – The new standard for digital preservation of cinematographic works

EN 17650 is a proposed new European Standard for the digital preservation of cinematographic works. It allows organizing of content in a systematic way, the so called Cinema Preservation Package (CPP). The standard defines methods to store content in physical and logical structures and describes relationships and metadata for its components. The CPP uses existing XML schemes, in particular METS, EBUCore and PREMIS to store structural, descriptive, technical and provenance metadata. METS XML files with their core metadata contain physical and logical structures of the content, hash values and UUIDs to ensure data integrity and links to external metadata files to enrich the content with additional information. The content itself is stored based on existing public and industry standards, avoiding unnecessary conversion steps. The paper explains the concepts behind the new standard and specifies the usage and combinations of existing schemes with newly introduced metadata parameters.

Predicting Camera Color Quality

Color quality can be measured two ways. The first is target based where color-difference statistics are reported comparing image data with measurement-based colorimetric data. The second is based on measuring the camera sensor’s spectral sensitivities and calculating their similarity to a standard observer, for example, μ-factor. A computational experiment was performed where synthetic images of a variety of targets were rendered for four camera systems having μ-factors of 0.79, 0.88, 0.94, and 0.99. Each camera was profiled using the same target. Although profile color accuracy was acceptable for all the cameras, this did not predict the color accuracy for independent targets. μ-factor was a better predictor of color quality and its use is recommended when evaluating cameras for cultural heritage applications

Addressing the Challenges of Interoperability and Cultural Heritage Data

One of the ongoing challenges for effective utilization of heritage science data is the lack of access to well-organized and accessible extant data sets and the need to structure data in formats that allow interrogation and integration of related data. This need for data fusion expands to both subjective and objective measurements and descriptors, as well as a long-overdue need for established guidelines for metadata and shared terminologies, or more critically, ontologies. Research into this area has shown the need for Knowledge Organization Systems (KOS) that bridge and integrate multiple ontologies that address specific needs – for example the Getty Vocabularies for cultural heritage terms, the Linked Art model for a simplified core CIDOC-CRM, as well as the OBO Foundry and other scientific ontologies for measurements and heritage science terminology.[1]

Evaluation of Text Legibility in Alternative Imaging Approaches to Microfiche Digitization

Microfiche was a common format used in microforms reproductions of documents, extensively used for archival storage before the move to digital formats. While contemporary documents are still available for digitization, others from older historical periods are no longer physically accessible for various reasons. In some cases, their microfiche copies are available, making microfiche digitization a must. However, a microfiche reader is not always available and, even then, it is a machine made for the purpose of reading and not for data collection. In this work, the performance two imaging devices are evaluated as alternatives to the traditional microfiche reader, by means of optical character recognition (OCR). Results show that this alternative surpasses the performance of a microfiche reader in terms of text legibility.

The Sustainable Development of Sports Culture via Digital Archives

This study engages in the process of digitizing information concerning interviews of veteran athletes and collections of historical relics, and then establishes metadata pertaining to the archival process. The fruits of this labor are to be demonstrated on the Historical Sport Relics Digital Museum website for public interests. The purpose of this work is to use digital archiving as a method to preserve the culture, heritage, and values of Taiwan’s sport history, as well as to develop value-added applications.