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Interactive Pixel Based file formats have been produced over the course of the last two decades by many stakeholders active in the Heritage sector. It is a global story. Its use has facilitated research and dissemination strategies for vast numbers of artefacts, conservation interactions and scientific studies. The technology has been explored and elaborated via varying technical strategies; each one of them delivering specific results with visual benefits and paths for computational research. This situation is also reflected in the many naming conventions used for this technology: Relightable Images, Multi-Light Image Collections, Reflectance Transformation Imaging, Multi-Light Images, Multi-Light Reflectance, … . It has been the aim of the pixel+ project to bring the existing spectrum of these technologies closer together, by A. creating a universal web interface for its most popular processed output formats (objective 1), B. finding solutions to store and disseminate these type of multi-layered datasets in a new open, web optimize file format (objective 2), C. providing a conversion tool allowing stakeholders to optimize their existing datasets into the new file format (objective 2). Throughout the pixel+ project the general collective term for the targeted technology is Single Camera Multi-Light (SCML), the newly proposed file format: .scml. SCML techniques have been used extensively to study objects under varying light conditions. Intuitively, we humans perform this technique to study local surface detail, the shape of an object or reflectance properties, e.g. by using a flash light at raking angles to reveal the tiny surface details. These visual cues that change under varying light conditions are captured with cameras and serve as input for various algorithms that model this light dependent pixel intensity (i.e. formulate the final pixel color as a function of the light direction) or even learn surface and material properties from these cues. Two major SCML approaches lay in the scope of the pixel+ project. On the one hand the Belgian system of the Portable Light Dome (PLD) and on the other hand the US solution with Reflectance Transformation Imaging (RTI); sometimes also known as Polynomial Texture Mapping (PTM), piloted by Cultural Heritage Imaging (CHI, San Francisco). The latter includes the axe expanded by mainly ISTI/CNR researchers in Italy. Both approaches have proven their added value over the last 20 years for the visual documenting, study and multi-layered digital preservation of heritage objects. In the meantime countless past and ongoing research and imaging projects, initiated and funded all over the world, illustrate this clearly. For all these projects and their outcomes pixel+ has provided new solutions. Both platforms have been developed by separate research groups, with a different focus. This resulted in dissimilar interactive pixel based file formats, making it challenging to interchange the information processed and stored in their respective output datasets. Therefore, the pixel+ project aimed to merge the technologies of both approaches into a single consultation platform that will be capable of displaying all existing interactive pixel based file formats with their respective viewing modes and metadata. This viewer has the ability to illuminate the virtual model of the heritage object and consult the processed datasets with visual styles developed within the research spheres of both platforms. Moreover, as both methods are alike in terms of required input and processed output, pixel+ focusses on other types of integration, resulting in new additional visual styles for processed data, as well as a novel reprocessing pipeline for existing source image sets. Because RTI and PLD are still relatively young technologies, knowledge of their technicalities and wide range of potential benefits is still sub-par. A new dissemination website has been launched which explains these technologies and their derivatives. It contains best practices and use cases, and shares community updates. As it's in the interest of the whole community, the website doesn’t shy away from discussing other future computational photography techniques to further elaborate viewing, processing and/or digital preserving interactive pixel based file formats. The source codes of both the pixel+ viewer and this companion website are on GitHub. ispartof: BRAIN-be Pioneer Projects pages:1-51 status: Published online |
