New methods and tools for 3D-modeling of large scale outdoor scenes using range and color images


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My dissertation develops new tools and methods for creating digital models from range and color images, with emphasis in large-scale outdoor scenes. First, it addresses the problem of range and color image registration. In this area, I introduce a semi-automatic tool for range and color image registration that makes use of line-features to solve for the position and orientation of the digital camera. This allows to efficiently register images of urban scenery. Secondly, I present a registration technique that uses the shadows cast by the sun as cues find the correct camera pose, which was successfully applied in the creation of a digital model of an archaeological excavation in Monte Polizzo, Sicily. I also address the problem of building seamless integrated texture maps from images that were taken under different illumination conditions. To achieve this I present two different solutions. The first one is to align all the images to the same illumination. For this, I have developed a technique that computes a relighting operator over the area of overlap of a pair of images, which is then used to relight the entire image. The proposed method can handle images with shadows and can effectively remove the shadows from the image, if required. The second technique uses the ratio of two images to factor out the diffuse reflectance of an image from its illumination. This is achieved without any light measuring device. By computing the actual reflectance we remove from the images any effects of the illumination, which then allows to create new renderings under novel illumination conditions.

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