University of Southampton OCS (beta), CAA 2012

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Advances in the computational photography tools: Reflectance Transformation Imaging (RTI) and Algorithmic Rendering (AR)
Carla Schroer, Mark Mudge

Last modified: 2011-12-11


This talk will present an overview of the latest developments in RTI and AR technologies.

Reflectance Transformation Imaging. RTI creates digital representations from image sequences where light is projected from different directions. The lighting information from this image set is mathematically synthesized into an RTI image, enabling a user to interactively re-light and enhance the subject's surface in incredible detail. 

We will examine multi-spectral RTI and the hidden topological landscapes disclosing under-painting and drawings in the infra-red and the fine surface information disclosed in ultra-violet wavelengths.  We will discuss RTI of subjects under magnification using macro and microscopic optics as well as updates in viewing technology.

New developments in the related technology Algorithmic Rendering (AR), which uses the same data sets as RTI, will also be presented. The development of new AR technology by Princeton University and Cultural Heritage Imaging is supported by a significant grant from the National Science Foundation.  The end-product will be an open-source tool which will extract and merge visual information available only under certain lighting conditions, certain wavelengths, or certain imaging modalities. Users will be able to generate high quality, comprehensible illustrations for documentation, scientific study, and sharing with colleagues, collection visitors, and the public.

New software tools to better collect and manage the metadata surrounding the creation of RTI and AR will also be discussed.  This “digital lab notebook” is a critical element in the generation of scientifically reliable digital representations that enable future reuse for novel purposes, assist the long-term digital preservation of the virtual representations, and aid the physical conservation of the digitally represented museum materials.

RTI is undergoing rapid adoption in the US museum conservation field.  A US Institute of Museum and Library Services (IMLS) sponsored training program is bringing a four day RTI training to all six masters programs in art conservation in North America, as well as four regional museum trainings open to museum professionals.  As a result of this program over 150 museum professionals and pre-professionals will be fully trained in RTI technology, in addition to the many institutions that are adopting RTI outside of this program including the Museum of Modern Art and the Metropolitan Museum of Art.


RTI, AR, Computational Photography