Mark Mudge

Illuminating the past: state of the art

Virtual reconstruction and representation of historical environments and objects have been of research interest for nearly two decades. Physically based and historically accurate illumination allows archaeologists and historians to authentically visualise a past environment to deduce new knowledge. This report reviews the current state of illuminating cultural heritage sites and objects using computer graphics for scientific, preservation and research purposes. We present the most noteworthy and up-to-date examples of reconstructions employing appropriate illumination models in object and image space, and in the visual perception domain. Finally, we also discuss the difficulties in rendering, documentation, validation and identify probable research challenges for the future. The report is aimed for researchers new to cultural heritage reconstruction who wish to learn about methods to illuminate the past.

Dynamic shading enhancement for reflectance transformation imaging

We propose a set of dynamic shading enhancement techniques for improving the perception of details, features, and overall shape characteristics from images created with Reflectance Transformation Imaging (RTI) techniques. Selection of these perceptual enhancement filters can significantly improve the users ability to interactively inspect the content of 2D RTI media by zooming, panning, and changing the illumination direction. In particular, we present two groups of strategies for RTI image enhancement based on two main ideas: exploiting the unsharp masking methodology in the RTI-specific context; and locally optimizing the incident light direction for improved RTI image sharpness and illumination of surface features. The Result section will present a number of datasets and compare them with existing techniques.

Image-Based Empirical Information Acquisition, Scientific Reliability, and Long-Term Digital Preservation for the Natural Sciences and Cultural Heritage

The tools and standards of best practice adopted by natural science (NS) and cultural heritage (CH) professionals will determine the digital future of NS and CH digital imaging work. This tutorial discusses emerging digital technologies and explores issues influencing widespread adoption of digital practices for NS and CH. The tutorial explores a possible digital future for NS and CH through key concepts; adoption of digital surrogates, empirical (scientific) provenance, perpetual digital conservation, and ‘born archival’ semantic knowledge management. The tutorial discusses multiple image based technologies along with current research including; Reflectance Transformation Imaging (RTI), Photometric Stereo, and new research in the next generation of multi-view RTI. This research involves extending stereo correspondence methods. These technologies permit generation of digital surrogates that can serve as trusted representations of ‘real world’ content. The tutorial explores how empirical provenance contributes to the reliability of digital surrogates, and how perpetual digital conservation can ensure that digital surrogates will be archived and available for future generations. The tutorial investigates the role of semantically based knowledge management strategies and their use in simplifying ease of use by natural science and CH professionals as well as long term preservation activities. The tutorial also investigates these emerging technologies’ potential to democratize digital technology, making digital tools and methods easy to adopt and make NS and CH materials widely available to diverse audiences. The tutorial concludes with handson demonstrations of image-based capture and processing methods and a practical problem solving Q&A with the audience.

Editorial: Special Section on Cultural Heritage

Over the last two decades, there have been many high profile success stories where cutting edge computer graphics (CG) technology was used in collaboration with cultural heritage (CH) professionals to unlock the secrets of humanity’s legacy. Well known examples include the empirical 3D acquisition of Michelangelo’s David, the laser scan-based 3D mapping of the tombs found in the Valley of the Kings and the decipherment of the instructions to and the operation of the 2nd-century BCE Antikythera Mechanism—arguably the first computer in human kind history. This special edition of Computers and Graphics contains new work that continues this tradition.

Cultural heritage and computer graphics: what are the issues?

In many parts of the world, governments are allocating more nancial support for projects that use technology to preserve and communicate cultural heritage. This panel considers several key related questions: What is the role of computer graphics in these projects? Is cultural heritage just an interesting area for using graphics, or does it present unique research challenges? How successful have projects in computer graphics and cultural heritage been? Are the basic tools and techniques developed in graphics adequate for use in cultural heritage, or are we missing opportunities?

Editorial: Computers & Graphics journal special section on Cultural Heritage

An increasing number of Cultural Heritage professionals are using Computer Graphics technology to unlock and document the secrets of humanity’s legacy. Earlier this year, a recent special issue of this journal published some of the important results from the intersection of these two fields [1]. The level of interest and the quality of submissions was such that an additional special section is necessary to showcase three further exciting results. Andujar et al. [2] discuss the design of the user interface for the virtual inspection of the entrance of the Ripoll Monastery in Spain. The authors analyze the requirements from museum curators and discuss the main interface design decisions. Results of a user study comparing the proposed user interface with alternative approaches are provided together with a discussion of its benefits to the Cultural Heritage Community. Adán et al. [3] propose a semi-automatic approach for the reconstruction of archeological pieces through the integration of a set of only a few segments of the original piece. This highly complex problem is tackled by considering hybrid human/computer strategies. Hypotheses, models and integration solutions originating from both humans and computers are continuously updated until an agreement is reached. This restoration approach has been tested on a set of ancient fractured pieces belonging to the remains of Roman sculptures at the well known Mérida site. Finally, Ritz et al. [4] present a novel 3D geometry acquisition technique at high resolution based on structured light reconstruction with a low-cost projector–camera system. The proposed setup allows reconstruction of the finest details of small cultural heritage objects and enables accurate height field measurements which can be used as input to physically based renderers. The cooperation between the diverse fields of cultural heritage and computer graphics is maturing. Researchers and practitioners in both fields now regularly work closely together. Many more high quality publications are expected as the synergies between the two disciplines are realized in future collaborations.