TY - RPRT A1 - Grundhöfer, Anselm A1 - Seeger, Manja A1 - Häntsch, Ferry A1 - Bimber, Oliver T1 - Dynamic Adaptation of Projected Imperceptible Codes N2 - 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. KW - Association for Computing Machinery / Special Interest Group on Graphics KW - CGI KW - Maschinelles Sehen KW - Erweiterte Realität KW - Kamera Tracking KW - Projektion KW - Augmented Reality KW - Camera Tracking KW - Projection Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-8168 ER - TY - RPRT A1 - Föckler, Paul A1 - Zeidler, Thomas A1 - Bimber, Oliver T1 - PhoneGuide: Museum Guidance Supported by On-Device Object Recognition on Mobile Phones N2 - We present PhoneGuide – an enhanced museum guidance approach that uses camera-equipped mobile phones and on-device object recognition. Our main technical achievement is a simple and light-weight object recognition approach that is realized with single-layer perceptron neuronal networks. In contrast to related systems which perform computational intensive image processing tasks on remote servers, our intention is to carry out all computations directly on the phone. This ensures little or even no network traffic and consequently decreases cost for online times. Our laboratory experiments and field surveys have shown that photographed museum exhibits can be recognized with a probability of over 90%. We have evaluated different feature sets to optimize the recognition rate and performance. Our experiments revealed that normalized color features are most effective for our method. Choosing such a feature set allows recognizing an object below one second on up-to-date phones. The amount of data that is required for differentiating 50 objects from multiple perspectives is less than 6KBytes. KW - Neuronales Netz KW - Objekterkennung KW - Handy KW - Museum KW - Mobile phones KW - object recognition KW - neural networks KW - museum guidance Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-6500 ER - TY - INPR A1 - Wetzstein, Gordon A1 - Bimber, Oliver T1 - A Generalized Approach to Radiometric N2 - We propose a novel method that applies the light transport matrix for performing an image-based radiometric compensation which accounts for all possible types of light modulation. For practical application the matrix is decomposed into clusters of mutually influencing projector and camera pixels. The compensation is modeled as a linear system that can be solved with respect to the projector patterns. Precomputing the inverse light transport in combination with an efficient implementation on the GPU makes interactive compensation rates possible. Our generalized method unifies existing approaches that address individual problems. Based on examples, we show that it is possible to project corrected images onto complex surfaces such as an inter-reflecting statuette, glossy wallpaper, or through highly-refractive glass. Furthermore, we illustrate that a side-effect of our approach is an increase in the overall sharpness of defocused projections. KW - Association for Computing Machinery / Special Interest Group on Graphics KW - CGI KW - Maschinelles Sehen Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-7625 ER - TY - RPRT A1 - Wetzstein, Gordon A1 - Bimber, Oliver T1 - Radiometric Compensation through Inverse Light Transport N2 - Radiometric compensation techniques allow seamless projections onto complex everyday surfaces. Implemented with projector-camera systems they support the presentation of visual content in situations where projection-optimized screens are not available or not desired - as in museums, historic sites, air-plane cabins, or stage performances. We propose a novel approach that employs the full light transport between a projector and a camera to account for many illumination aspects, such as interreflections, refractions and defocus. Precomputing the inverse light transport in combination with an efficient implementation on the GPU makes the real-time compensation of captured local and global light modulations possible. KW - Association for Computing Machinery / Special Interest Group on Graphics KW - CGI KW - Maschinelles Sehen KW - Projektionssystem KW - radiometrische Kompensation KW - Licht Transport KW - Projector-Camera Systems KW - Radiometric Compensation KW - Inverse Light Transport Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-8126 ER -