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.