Browsing by Subject "cultural heritage"

Now showing 1 - 4 of 4
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    Appleton Celebrating 125 years 1881-2006
    (2007) Bigley, Ann
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    Digitally Reconstructing and Presenting A Historical Site over a span of Time
    (2022-01) Shervheim, Daniel
    In this thesis we present our work on Virtual Fort Snelling. Virtual Fort Snelling is an interactive experience that allows users to visualize the fort area over the past 200 years. The creation of Virtual Fort Snelling raised a number of interesting technical challenges. In this work we discuss our 3D modeling, texturing, and shading pipeline. We also discuss our scene lighting and instanced vegetation rendering systems. As well as our content delivery, caching, and presentation systems. Finally, we measure and analyze our vegetation rendering system, and discuss our future plans.
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    Image-Based Relighting of 3D Objects from Flash Photographs
    (2019-05) Tetzlaff, Michael
    Photography is a remarkable technology that allows us to capture and reproduce the appearance of the real world. Although photographs are two-dimensional and static, their capabilities have been extended into higher dimensions through the development of techniques like photogrammetry, image-based rendering, and image-based relighting. Such prior work, however, has struggled to support dynamic illumination of the subject while still representing specular reflections accurately, especially for subjects that exhibit heterogeneity in their appearance. The most successful results in this direction usually require thousands of images. This dissertation introduces a new paradigm for image-based relighting of 3D objects that requires no more than a few hundred flash photographs. The flash lighting configuration is conveniently found on most commodity cameras. After being processed using traditional photogrammetry, the flash images serve as a collection of virtual light sources in a relighting system, through the power of Cook-Torrance microfacet theory. This approach produces new images of 3D objects that effectively retain the photographic accuracy of the subject's color appearance from the original flash photos. The same flash images can also be used to estimate reflectance parameters that improve the accuracy of the relighting technique. This rendering method can even be used to emulate lighting conditions -- both outdoor and indoor -- that are very different than flash. This work proceeds to show how the intensities of point light sources derived from the collection of flash images can be chosen to effectively emulate the intended environment. Although similar results have been previously achieved using thousands of images, the method shown here can be effective with a few hundred images or less. However, this reduction is not without limitation; a shinier object requires more photographs to avoid discontinuity between the intended environment and its reflection. To address this one limitation, this work ultimately develops a fidelity metric for assessing whether reflections of individual light sources are likely to be discernible when the object is relit. This metric is a heuristic solution which estimates the magnitude of this issue by quantifying the degree of overlap in specular reflections between similar images in the dataset. It is believed to be the first work which assesses the fidelity of how highlights are depicted when an object is relit using a limited number of views. This solution is shown to be generally effective and serves as a foundation which can be built upon by future metrics.
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    Serving the Inanimate Constituency: Re-Centering Collections in the Work of Museums
    (2016-05) Clark, Kristina
    Museums play a critical role in protecting society's collective heritage by protecting, caring for, and sharing collections items for the public trust. A combination of developments has led museums to shift resources from collections towards work on audience engagement, innovation, and demonstrating impact. But strategies exist for museums to keep collections at the center of their work, thus helping to protect museums' essential and niche function to society. The Cycling Museum of Minnesota offers an illustration of what re-centering collections looks like in practice.