Papers by Anselm Grundhöfer
Joint Eurographics - IEEE TCVG Symposium on Visualization, 2004
Wepresent a three pass occlusion culling algorithm, which makes efficient use of hardware support... more Wepresent a three pass occlusion culling algorithm, which makes efficient use of hardware support. Our geo-scientific sub-surface data sets consist typically of a set of high resolution height fields, polygonal objects, and volume slices and lenses. The first rendering pass computes a z-buffer image using low resolution objects and the non-transparent volume objects. During the second pass, we render
2013 IEEE Conference on Computer Vision and Pattern Recognition Workshops, 2013
Proceedings of the 3rd international conference on Computer graphics and interactive techniques in Australasia and South East Asia - GRAPHITE '05, 2005
This paper presents a non-conservative occlusion culling technique for dynamic scenes with animat... more This paper presents a non-conservative occlusion culling technique for dynamic scenes with animated or usermanipulated objects. We use a multi-pass algorithm, which decides the visibility based on low level of detail representations of the geometric models. Our approach makes efficient use of hardware support for occlusion queries and avoids stalling the graphics pipeline. We have tested our approach for large real-world models from different areas. Our results show that the algorithm performs well for medium complex scenes with 5 to 20 million triangles. with a very low number of hardly noticeable pixel errors, typically in the range of 0.02 percent of the total number of visible pixels.
IEEE Virtual Reality Conference (VR 2006), 2006
ACM SIGGRAPH 2008 talks on - SIGGRAPH '08, 2008
We synchronize cameras and analog lighting with high speed projectors. Radiometric compensation a... more We synchronize cameras and analog lighting with high speed projectors. Radiometric compensation allows displaying flexible blue screens on arbitrary real world surfaces. A fast temporal multiplexing of coded projection and flash illumination enables professional chroma keying and camera tracking for non-studio film sets.
2010 IEEE Computer Society Conference on Computer Vision and Pattern Recognition - Workshops, 2010
CAMShift is a well-established and fundamental algorithm for kernel-based visual object tracking.... more CAMShift is a well-established and fundamental algorithm for kernel-based visual object tracking. While it performs well with objects that have a simple and constant appearance, it is not robust in more complex cases. As it solely relies on back projected probabilities it can fail in cases when the object's appearance changes (e.g., due to object or camera movement, or due to lighting changes), when similarly colored objects have to be re-detected or when they cross their trajectories. We propose low-cost extensions to CAMShift that address and resolve all of these problems. They allow the accumulation of multiple histograms to model more complex object appearances and the continuous monitoring of object identities to handle ambiguous cases of partial or full occlusion. Most steps of our method are carried out on the GPU for achieving real-time tracking of multiple targets simultaneously. We explain efficient GPU implementations of histogram generation, probability back projection, computation of image moments, and histogram intersection. All of these techniques make full use of a GPU's high parallelization capabilities.
Lecture Notes in Computer Science, 2011
We show how the intrinsically performed JPEG compression of many digital still cameras leaves mar... more We show how the intrinsically performed JPEG compression of many digital still cameras leaves margin for deriving and applying image-adapted coded apertures that support retention of the most important frequencies after compression. These coded apertures, together with subsequently applied image processing, enable a higher light throughput than corresponding circular apertures, while preserving adjusted focus, depth of field, and bokeh. Higher light throughput leads to proportionally higher signal-to-noise ratios and reduced compression noise, oralternatively-to lower shutter times. We explain how adaptive coded apertures can be computed quickly, how they can be applied in lenses by using binary spatial light modulators, and how a resulting coded bokeh can be transformed into a common radial one.
We present a three pass occlusion culling algorithm, which makes efficient use of hardware suppor... more We present a three pass occlusion culling algorithm, which makes efficient use of hardware support. Our geo-scientific sub-surface data sets consist typically of a set of high resolution height fields, polygonal objects, and volume slices and lenses. The first rendering pass computes a z-buffer image using low resolution objects and the non-transparent volume objects. During the second pass, we render the same objects against the z-buffer of the first pass while submitting an occlusion query with each object. The third pass reads this occlusion information back from the graphics hardware and renders only those high resolution objects, for which the corresponding low resolution objects were not completely occluded. To avoid fill rate bottle necks, the first two passes may be rendered to a low resolution window. Our implementation shows frame rate improvements for all test cases while introducing only a small overhead and no or hardly noticeable errors. Our non-conservative approach does not require front to back sorting and it works well for dynamic scenes.
2007 6th IEEE and ACM International Symposium on Mixed and Augmented Reality, 2007
: A TV studio mock-up with back projection encoding adaptive imperceptible patterns (a), images c... more : A TV studio mock-up with back projection encoding adaptive imperceptible patterns (a), images captured by a synchronized camera at 120 Hz (b, c), computed foreground matte from real-time flash keying (d), extracted multi-resolution marker pattern for in-shot camera pose estimation (e), and composite frame with virtual background and 3D augmentation (f).
ACM SIGGRAPH 2005 Sketches on - SIGGRAPH '05, 2005
We show how view-dependent image-based and geometric warping, radiometric compensation, and multi... more We show how view-dependent image-based and geometric warping, radiometric compensation, and multi-focal projection enable a view-dependent stereoscopic visualization on ordinary (geometrically complex, colored and textured) surfaces within everyday environments. Special display configurations for immersive or semi-immersive AR/VR applications that require permanent and artificial projection canvases might become unnecessary. We demonstrate several adhoc visualization examples in a real architectural and museum application context.
SIGGRAPH 2009: Talks on - SIGGRAPH '09, 2009
With adaptive coded aperture projection, we present solutions for taking projectors to the next l... more With adaptive coded aperture projection, we present solutions for taking projectors to the next level. By placing a programmable liquid crystal array at a projectors aperture plane we show how the depth of field (DOF) of a projection can be greatly enhanced. This allows focussed imagery to be shown on complex screens with varying distances to the projectors focal plane,
Proceedings of the SIGGRAPH 2003 conference on Sketches & applications in conjunction with the 30th annual conference on Computer graphics and interactive techniques - GRAPH '03, 2003
We present techniques which create a consistent illumination between real and virtual objects ins... more We present techniques which create a consistent illumination between real and virtual objects inside an application specific optical see-through display: the Virtual Showcase. We use projectors and cameras to capture reflectance information from diffuse real objects and to illuminate them under new synthetic lighting conditions. Matching direct and indirect lighting effects, such as shading, shadows, reflections and color bleeding can be approximated at interactive rates in such a controlled mixed environment.
Practical Holography XIX: Materials and Applications, 2005
Holography and computer graphics are being used as tools to solve individual research, engineerin... more Holography and computer graphics are being used as tools to solve individual research, engineering, and presentation problems within several domains. Up until today, however, these tools have been applied separately. Our intention is to combine both technologies to create a powerful tool for science, industry and education. We are currently investigating the possibility of integrating computer generated graphics and holograms. This paper gives an overview over our latest results. It presents several applications of interaction techniques to graphically enhanced holograms and gives a first glance on a novel method that reconstructs depth from optical holograms. -weimar.de/medien/AR; www.holographics.de (high-resolution color versions of images presented in this paper are available online)
Virtual studio technology plays an important role for modern television productions. Blue-screen ... more Virtual studio technology plays an important role for modern television productions. Blue-screen matting is a common technique for integrating real actors or moderators into computer generated sceneries. Augmented reality offers the possibility to mix real and virtual in a more ...
ACM SIGGRAPH 2011 Posters on - SIGGRAPH '11, 2011
A variety of standard video modes that stretch or zoom lower resolution video content linearly to... more A variety of standard video modes that stretch or zoom lower resolution video content linearly to take full advantage of large screen sizes have been implemented in TV sets. When content and screen aspect ratios differ, format proportions may be compromised, video content may be clipped, or screen regions may remain unused. Newer techniques, such as video retargeting and video
SIGGRAPH 2009: Talks on - SIGGRAPH '09, 2009
... Downloads (12 Months), 105. View colleagues of Daniel Kurz. Sebastian Thiele No contact infor... more ... Downloads (12 Months), 105. View colleagues of Daniel Kurz. Sebastian Thiele No contact information provided yet. Bibliometrics: publication history ... Downloads (6 Weeks), 5. Downloads (12 Months), 36. View colleagues of Sebastian Thiele. Ferry Häntsch ...
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Papers by Anselm Grundhöfer