164 research outputs found
3D Acquisition of Mirroring Objects using Striped Patterns
No full textObjects with mirroring optical characteristics are left out of the scope of most 3D scanning methods. We present here a new automatic acquisition approach, shape-from-distortion, that focuses on that category of objects, requires only a still camera and a color monitor, and produces range scans (plus a normal and a reflectance map) of the target. Our technique consists of two steps: first, an improved environment matte is captured for the mirroring object, using the interference of patterns with different frequencies to obtain sub-pixel accuracy. Then, the matte is converted into a normal and a depth map by exploiting the self-coherence of a surface when integrating the normal map along different paths. The results show very high accuracy, capturing even smallest surface details. The acquired depth maps can be further processed using standard techniques to produce a complete 3D mesh of the object
Shape from Distortion: 3D Range Scanning of Mirroring Objects
No full textObjects with mirroring surfaces are left out of the scope of most recent 3D scanning methods. We developed a new acquisition approach, shape-from-distortion, that focuses on that category of objects, requires only a still camera and a monitor, and generates high quality range scans (plus a normal field). Our contributions are a novel acquisition technique based on environment matting [Chuang et al. 2000] and corresponding geometry reconstruction method that recovers a very precise geometry model for mirroring objects
Printing Spatially-Varying Reflectance
No full textAlthough real-world surfaces can exhibit significant variation in materials --- glossy, diffuse, metallic, etc. --- printers are usually used to reproduce color or gray-scale images. We propose a complete system that uses appropriate inks and foils to print documents with a variety of material properties. Given a set of inks with known Bidirectional Reflectance Distribution Functions (BRDFs), our system automatically finds the optimal linear combinations to approximate the BRDFs of the target documents. Novel gamut-mapping algorithms preserve the relative glossiness between different BRDFs, and halftoning is used to produce patterns to be sent to the printer. We demonstrate the effectiveness of this approach with printed samples of a number of measured spatially-varying BRDFs
Gene-expression signature of adhesion/growth-regulatory tissue lectins (galectins) in transitional cell cancer and its prognostic relevance
No full textAIMS: Lectins, and especially galectins, appear to be important in malignancy-associated processes. The aim was to analyse comprehensively the presence of galectins in urothelial tumours. METHODS AND RESULTS: Non-cross-reactive antibodies against seven family members from the three subgroups (prototype: galectin-1, -2 and -7; chimera type: galectin-3; tandem-repeat type: galectin-4, -8 and -9) were used. Gene expression was monitored in specimens of normal urothelium, fresh tumour tissue and cell lines by real-time polymerase chain reaction (PCR). The presence and evidence of tumour-associated up-regulation were shown for galectin-1 and -3. This was less clear-cut for galectin-4 and -8. Galectin-7 was expressed in all cell lines; galectin-2 and -9 were detected at comparatively low levels. Galectin-2, -3 and -8 up-regulation was observed in superficial tumours, but not in muscle-invasive tumours (P < 0.05). Immunoreactivity correlated with tumour grading for galectin-1, -2 and -8, and disease-dependent mortality correlated with galectin-2 and -8 expression. Binding sites were visualized using labelled galectins. CONCLUSIONS: The results demonstrate a complex expression pattern of the galectin network in urothelial carcinomas. Galectin-1, -2, -3 and -8 are both potential disease markers and also possible targets for bladder cancer therap
Path Regeneration for Interactive Path Tracing
No full textRendering of photo-realistic images at interactive frame rates is currently an extensively researched area of computer graphics.Many of these approaches attempt to utilize the computational power of modern graphics hardware for ray tracing based methods. When using path tracing algorithms the ray paths are highly incoherent, hence we propose an efficient technique that minimizes the divergence in execution flow and ensures full utilization by intelligently regenerating the paths. We analyze the conditions under which our improvements provide the highest speedup, and demonstrate the performance of the overall system by rendering interactive previews of global illumination solutions using (bidirectional) path tracing with progressive refinement.Rendering of photo-realistic images at interactive frame rates is currently an extensively researched area of computer graphics.Many of these approaches attempt to utilize the computational power of modern graphics hardware for ray tracing based methods. When using path tracing algorithms the ray paths are highly incoherent, hence we propose an efficient technique that minimizes the divergence in execution flow and ensures full utilization by intelligently regenerating the paths. We analyze the conditions under which our improvements provide the highest speedup, and demonstrate the performance of the overall system by rendering interactive previews of global illumination solutions using (bidirectional) path tracing with progressive refinement.Eurographics 2010 - Short PapersRenderin
Procedural Descriptions of Anisotropic Noisy Textures by Example
No full textThis short paper introduces a new approach to automate the creation of procedural anisotropic noisy textures by using an example. As for past approaches that allow one to obtain procedural descriptions of stochastic textures, it uses a sum of multi-scale noise functions and a combined spectral / histogram-based approach. The improvement, here, consists in better controlling the spectral domain by using Gabor noise functions. This allows us to extend the range of textures that can be addressed, while bringing a number of advantages compared to classical examplebased texture synthesis: extreme compactness, continuous definition over infinite space, easy extension to solid (even animated solid) textures and straight texture value computation in the fragment shader.This short paper introduces a new approach to automate the creation of procedural anisotropic noisy textures by using an example. As for past approaches that allow one to obtain procedural descriptions of stochastic textures, it uses a sum of multi-scale noise functions and a combined spectral / histogram-based approach. The improvement, here, consists in better controlling the spectral domain by using Gabor noise functions. This allows us to extend the range of textures that can be addressed, while bringing a number of advantages compared to classical examplebased texture synthesis: extreme compactness, continuous definition over infinite space, easy extension to solid (even animated solid) textures and straight texture value computation in the fragment shader.Eurographics 2010 - Short PapersImages, Geometry, and Musi
gCubik+i Virtual 3D Aquarium: Interfacing a Graspable 3d Display with a Tabletop Display
No full textWe propose gCubik+i as a new interactive platform that naturally interfaces a 3D display with a tabletop display. The proposed platform is suitable for group collaboration and it introduces two novel interaction paradigms to existing tabletop display applications: 1) natural switching between the shared working spaces of the table and the users hands; and 2) transforming static 2D images into interactive 3D images that can be viewed and manipulated as if holding a real object. This paper describes the conceptual design and prototype implementation of the gCubik+i platform along with a description of its 3D virtual aquarium application.Eurographics 2010 - Short PapersInteraction and Application
Crustal and Sedimentary Structures and Geodynamic Evolution of the West Antarctic Continental Margin and Pine Island Bay
No full textSince the last glacial maximum the West Antarctic Ice Sheet (WAIS) with a base mostly beneath the present-day sea-level has experienced dramatic volume changes within short periods of time. Studies are urgently required to show how these short-term variations are related to volume changes in the older geological past. Next to the ice drainage basins of the Weddell Sea and the Ross Embayment, Pine Island Bay forms the third-largest outflow area for the West Antarctic ice-shield. The main ice streams from the WAIS into Pine Island Bay flow through the Pine Island and Thwaites Glacier systems, through which most of the glacial-marine sediments onto the shelf of Pine Island Bay and across the continental slope into the deep sea have been transported. Geophysical surveys of the sedimentary sequences and the underlying basement of the shelf and slope of the southern Amundsen Sea, Pine Island Bay and its adjacent continental rise would allow reconstructions of the formation of the tectonic and older sedimentary processes as well as to find out about the history of large-scale glaciation in West Antarctica. Accurate models of the geodynamic- tectonic evolution contain some of the most important parameters for understanding and reconstruction of the palaeo-environment. The following objectives will be addressed during ANT XXflII4 as part of a cooperative project between the Vernadsky Institute in Moscow (Dr. Gleb Udintsev) and AWl:K. Gohl, G. Uenzelmann-Neben, G. Eagles, A. Fahl, T. Feigl, J. Grobys, J. Just, V. Leinweber, N. Lensch, C. Mayr, N. Parsiegla, N. Rackebrandt, P. Schloter, S. Suckro, K. Zimmermann, S. Gauger, H. Bohlmann, G. L. Netzeband, and P. Lemenkova. Crustal and Sedimentary Structures and Geodynamic Evolution of the West Antarctic Continental Margin and Pine Island Bay. Germany, Bremerhaven, 2006. doi: 10.13140/RG.2.2.16473.36961
Ray Tracing using Hierarchies of Slab Cut Balls
No full textIn this paper, bounding volume trees of slab cut balls are evaluated and compared with other types of trees for ray tracing. A novel tree construction algorithm is proposed, which utilizes a relative orientation heuristic between parent and child nodes. Also, a fast intersection test between a ray and a slab cut ball is presented. Experimental comparisons to other commonly used enclosing shapes reveal that the slab cut ball is attractive. In particular, the slab cut ball outperforms the sphere in all tested scenes with speed-up factors between 1 and 4.Eurographics 2010 - Short PapersRenderin
Segmental Brush Synthesis with Stroke Images
No full textWe present a new approach for synthesizing realistic brush strokes exploiting recent works of texture synthesis from stroke images. (See Figure 1). In our method, stroke images are automatically decomposed into a sequence of quad segments and stitched together along the path of user s input to produce final image. Numbers of methods using textures on digital painting have been explored; our usage of texture is novel in that the source image is typically a photo and the synthesis is fast enough to achieve realtime feedback. In contrast to previous methods, our approach allows a large variety of artistic brushes to be interactively simulated fairly so that unique media which haven t caught attention yet such as lipsticks or finger paint, are well reproduced. We shall show some artworks created using our method and demonstrate feasibility of our algorithm.We present a new approach for synthesizing realistic brush strokes exploiting recent works of texture synthesis from stroke images. (See Figure 1). In our method, stroke images are automatically decomposed into a sequence of quad segments and stitched together along the path of user s input to produce final image. Numbers of methods using textures on digital painting have been explored; our usage of texture is novel in that the source image is typically a photo and the synthesis is fast enough to achieve realtime feedback. In contrast to previous methods, our approach allows a large variety of artistic brushes to be interactively simulated fairly so that unique media which haven t caught attention yet such as lipsticks or finger paint, are well reproduced. We shall show some artworks created using our method and demonstrate feasibility of our algorithm.We present a new approach for synthesizing realistic brush strokes exploiting recent works of texture synthesis from stroke images. (See Figure 1). In our method, stroke images are automatically decomposed into a sequence of quad segments and stitched together along the path of user s input to produce final image. Numbers of methods using textures on digital painting have been explored; our usage of texture is novel in that the source image is typically a photo and the synthesis is fast enough to achieve realtime feedback. In contrast to previous methods, our approach allows a large variety of artistic brushes to be interactively simulated fairly so that unique media which haven t caught attention yet such as lipsticks or finger paint, are well reproduced. We shall show some artworks created using our method and demonstrate feasibility of our algorithm.Eurographics 2010 - Short PapersImages, Geometry, and Musi
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