@techreport{KurzHaentschGrosseetal.2007,
  author    = {Kurz, Daniel and H{\"a}ntsch, Ferry and Grosse, Max and Schiewe, Alexander and Bimber, Oliver},
  title     = {Laser Pointer Tracking in Projector-Augmented Architectural Environments},
  doi       = {10.25643/bauhaus-universitaet.818},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-8183},
  year      = {2007},
  abstract  = {We present a system that applies a custom-built pan-tilt-zoom camera for laser-pointer tracking in arbitrary real environments. Once placed in a building environment, it carries out a fully automatic self-registration, registrations of projectors, and sampling of surface parameters, such as geometry and reflectivity. After these steps, it can be used for tracking a laser spot on the surface as well as an LED marker in 3D space, using inter-playing fisheye context and controllable detail cameras. The captured surface information can be used for masking out areas that are critical to laser-pointer tracking, and for guiding geometric and radiometric image correction techniques that enable a projector-based augmentation on arbitrary surfaces. We describe a distributed software framework that couples laser-pointer tracking for interaction, projector-based AR as well as video see-through AR for visualizations with the domain specific functionality of existing desktop tools for architectural planning, simulation and building surveying.},
  subject      = {Association for Computing Machinery / Special Interest Group on Graphics},
  language  = {en}
}
@techreport{GrosseBimber2008,
  author    = {Grosse, Max and Bimber, Oliver},
  title     = {Coded Aperture Projection},
  doi       = {10.25643/bauhaus-universitaet.1234},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20080227-13020},
  year      = {2008},
  abstract  = {In computer vision, optical defocus is often described as convolution with a filter kernel that corresponds to an image of the aperture being used by the imaging device. The degree of defocus correlates to the scale of the kernel. Convolving an image with the inverse aperture kernel will digitally sharpen the image and consequently compensate optical defocus. This is referred to as deconvolution or inverse filtering. In frequency domain, the reciprocal of the filter kernel is its inverse, and deconvolution reduces to a division. Low magnitudes in the Fourier transform of the aperture image, however, lead to intensity values in spatial domain that exceed the displayable range. Therefore, the corresponding frequencies are not considered, which then results in visible ringing artifacts in the final projection. This is the main limitation of previous approaches, since in frequency domain the Gaussian PSF of spherical apertures does contain a large fraction of low Fourier magnitudes. Applying only small kernel scales will reduce the number of low Fourier magnitudes (and consequently the ringing artifacts) -- but will also lead only to minor focus improvements. To overcome this problem, we apply a coded aperture whose Fourier transform has less low magnitudes initially. Consequently, more frequencies are retained and more image details are reconstructed.},
  subject      = {Association for Computing Machinery / Special Interest Group on Graphics},
  language  = {en}
}