@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}
}
@techreport{GrundhoeferBimber2008,
  author    = {Grundh{\"o}fer, Anselm and Bimber, Oliver},
  title     = {Dynamic Bluescreens},
  doi       = {10.25643/bauhaus-universitaet.1233},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20080226-13016},
  year      = {2008},
  abstract  = {Blue screens and chroma keying technology are essential for digital video composition. Professional studios apply tracking technology to record the camera path for perspective augmentations of the original video footage. Although this technology is well established, it does not offer a great deal of flexibility. For shootings at non-studio sets, physical blue screens might have to be installed, or parts have to be recorded in a studio separately. We present a simple and flexible way of projecting corrected keying colors onto arbitrary diffuse surfaces using synchronized projectors and radiometric compensation. Thereby, the reflectance of the underlying real surface is neutralized. A temporal multiplexing between projection and flash illumination allows capturing the fully lit scene, while still being able to key the foreground objects. In addition, we embed spatial codes into the projected key image to enable the tracking of the camera. Furthermore, the reconstruction of the scene geometry is implicitly supported.},
  subject      = {Association for Computing Machinery / Special Interest Group on Graphics},
  language  = {en}
}
@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{GrundhoeferSeegerHaentschetal.2007,
  author    = {Grundh{\"o}fer, Anselm and Seeger, Manja and H{\"a}ntsch, Ferry and Bimber, Oliver},
  title     = {Dynamic Adaptation of Projected Imperceptible Codes},
  doi       = {10.25643/bauhaus-universitaet.816},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-8168},
  year      = {2007},
  abstract  = {In this paper we present a novel adaptive imperceptible pattern projection technique that considers parameters of human visual perception. A coded image that is invisible for human observers is temporally integrated into the projected image, but can be reconstructed by a synchronized camera. The embedded code is dynamically adjusted on the fly to guarantee its non-perceivability and to adapt it to the current camera pose. Linked with real-time flash keying, for instance, this enables in-shot optical tracking using a dynamic multi-resolution marker technique. A sample prototype is realized that demonstrates the application of our method in the context of augmentations in television studios.},
  subject      = {Association for Computing Machinery / Special Interest Group on Graphics},
  language  = {en}
}
@article{GrundhoeferSeegerHaentschetal.2007,
  author    = {Grundh{\"o}fer, Anselm and Seeger, Manja and H{\"a}ntsch, Ferry and Bimber, Oliver},
  title     = {Coded Projection and Illumination for Television Studios},
  organization    = {Bimber, Fak. M, BUW},
  doi       = {10.25643/bauhaus-universitaet.800},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-8005},
  year      = {2007},
  abstract  = {We propose the application of temporally and spatially coded projection and illumination in modern television studios. In our vision, this supports ad-hoc re-illumination, automatic keying, unconstrained presentation of moderation information, camera-tracking, and scene acquisition. In this paper we show how a new adaptive imperceptible pattern projection that considers parameters of human visual perception, linked with real-time difference keying enables an in-shot optical tracking using a novel dynamic multi-resolution marker technique},
  subject      = {Association for Computing Machinery / Special Interest Group on Graphics},
  language  = {en}
}
@unpublished{GrundhoeferBimber2006,
  author    = {Grundh{\"o}fer, Anselm and Bimber, Oliver},
  title     = {Real-Time Adaptive Radiometric Compensation},
  doi       = {10.25643/bauhaus-universitaet.784},
  url       = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20111215-7848},
  year      = {2006},
  abstract  = {Recent radiometric compensation techniques make it possible to project images onto colored and textured surfaces. This is realized with projector-camera systems by scanning the projection surface on a per-pixel basis. With the captured information, a compensation image is calculated that neutralizes geometric distortions and color blending caused by the underlying surface. As a result, the brightness and the contrast of the input image is reduced compared to a conventional projection onto a white canvas. If the input image is not manipulated in its intensities, the compensation image can contain values that are outside the dynamic range of the projector. They will lead to clipping errors and to visible artifacts on the surface. In this article, we present a novel algorithm that dynamically adjusts the content of the input images before radiometric compensation is carried out. This reduces the perceived visual artifacts while simultaneously preserving a maximum of luminance and contrast. The algorithm is implemented entirely on the GPU and is the first of its kind to run in real-time.},
  subject      = {Maschinelles Sehen},
  language  = {en}
}