291 research outputs found
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
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
3D Data Acquisition - Eurographics 2002 Tutorial Notes
No full text3D scanners and image acquisition systems are rapidly becoming more affordable and allow to build highly accurate models of real 3D objects in a cost- and time-effective manner. This tutorial will present the potential of this technology, review the state of the art in model acquisition methods, and will discuss the 3D acquisition pipeline from physical acquisition until the final digital model. First, different optical scanning techniques (e.g. structured light triangulation, time-of-flight approaches) will briefly be presented. Other acquisition related issues including the design of the scanning studio will be discussed and evaluated. In the area of registration, we will consider both the problems of initially aligning individual scans, and of refining this alignment with variations of the Iterative Closest Point method. For scan integration and mesh reconstruction, we will compare various methods for computing, interpolating and approximating surfaces. We will then look at various ways in which surface properties such as color and reflectance can be extracted from acquired imagery. Finally, we will examine techniques for the efficient management and rendering of very large, attribute-rich meshes, including methods for the construction of simplified triangle-based representation and sample-based rendering approaches
7th ACM Symposium on Solid Modeling and Applications; Tutorial T2: A Framework for the Acquisition, Processing and Interactive Display of High Quality 3D Models
No full textAesop's Fables for Preschoolers
No full textThis is a large format booklet of 26 pages on heavy paper stock. It offers ten stories: LM, BS, GA, TH, DS, CP, “Boys and Frogs,” “Crab and Mother,” MM, and BC. The art is large, simple, playful: apt for preschoolers. The texts, as though typewritten, might use some words unfamiliar to preschoolers, like the “toils” of a hunter’s net or the grasshopper’s “fiddle.” I suspect that the texts, including their morals, were taken from some classic source. The tortoise wears glasses. The dog in DS has a good greed statement: “I need that bigger bone.” The moral for TH, which in its narrative speaks of “going slowly but steadily” is “The race is not always to the swift.” Will preschoolers understand that statement?No Autho
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
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
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
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