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Sharp volumetric billboard based characterization and modeling of complex 3D Ni/A1 high energy ball milled composites

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MECHANICS OF MATERIALS 2017年 108卷 93-106页

作者： Yushu, Dewen Lee, Sangmin Matous, Karel Univ Notre Dame Dept Aerosp & Mech Engn Notre Dame IN 46556 USA Univ Notre Dame Ctr Shock Wave Proc Adv React Mat Notre Dame IN 46556 USA

We present an innovative image-based modeling technique, based on Google Earth like algorithms, to effectively resolve intricate material morphology and address the computational complexity associated with heterogeneous materials. This sharp volumetric billboard algorithm stems from a volumetric billboard method, a multi-resolution modeling strategy in computer graphics. In this work, we enhance volumetric billboards through a sharpening filter to reconstruct the statistical information of heterogeneous systems. A hierarchy of microstructures is created for high energy ball milled Ni/A1 composites. We analyze the first- and second-order statistics of microstructures, and characterize both macro- and micro-mechanical material responses. Furthermore, we conduct a convergence study of the associated computational results. The statistical and mechanical robustness of data compression is demonstrated through the corresponding error analysis. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： image-based modeling Google Earth Volumetric billboard Model reduction Ni/Al composite Crystal plasticity

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modeling plants with sensor data

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Science in China(Series F) 2009年第3期52卷 500-511页

作者： MA Wei XIANG Bo ZHA HongBin LIU Jia ZHANG XiaoPeng Key Laboratory of Machine Perception (Ministry of Education) Peking University Beijing 100871 China LIAMA-NLPR Institute of Automation Chinese Academy of Sciences Beijing 100080 China

Sensor data, typically images and laser data, are essential to modeling real plants. However, due to the complex geometry of the plants, the measurement data are generally limited, thereby bringing great difficulties in classifying and constructing plant organs, comprising leaves and branches. The paper presents an approach to modeling plants with the sensor data by detecting reliable sharp features, i.e. the leaf apexes of the plants with leaves and the branch tips of the plants without leaves, on volumes recovered from the raw data. The extracted features provide good estimations of correct positions of the organs. Thereafter, the leaves are reconstructed separately by simply fitting and optimizing a generic leaf model. One advantage of the method is that it involves limited manual intervention. For plants without leaves, we develop an efficient strategy for decomposition-based skeletonization by using the tip features to reconstruct the 3D models from noisy laser data. Experiments show that the sharp feature detection algorithm is effective, and the proposed plant modeling approach is competent in constructing realistic models with sensor data.

关键词： plant modeling image-based modeling laser-based modeling sharp feature detection decomposition skeletonization

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A Re-Engineered Software Interface and Workflow for the Open-Source SimVascular Cardiovascular modeling Package

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JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME 2018年第2期140卷 024501页

作者： Lan, Hongzhi Updegrove, Adam Wilson, Nathan M. Maher, Gabriel D. Shadden, Shawn C. Marsden, Alison L. Stanford Univ Dept Pediat Clark Ctr E100B318 Campus Dr Stanford CA 94305 USA Univ Calif Berkeley Dept Mech Engn Berkeley CA 94720 USA Open Source Med Software Corp Santa Monica CA 90403 USA Stanford Univ ICME Stanford CA 94305 USA Stanford Univ Dept Bioengn Stanford CA 94305 USA

Patient-specific simulation plays an important role in cardiovascular disease research, diagnosis, surgical planning and medical device design, as well as education in cardiovascular biomechanics. SIMVASCULAR is an open-source software package encompassing an entire cardiovascular modeling and simulation pipeline from image segmentation, three-dimensional (3D) solid modeling, and mesh generation, to patient-specific simulation and analysis. SimVascular is widely used for cardiovascular basic science and clinical research as well as education, following increased adoption by users and development of a GATEWAY web portal to facilitate educational access. Initial efforts of the project focused on replacing commercial packages with opensource alternatives and adding increased functionality for multiscale modeling, fluid-structure interaction (FSI), and solid modeling operations. In this paper, we introduce a major SimVascular (SV) release that includes a new graphical user interface (GUI) designed to improve user experience. Additional improvements include enhanced data/project management, interactive tools to facilitate user interaction, new boundary condition (BC) functionality, plug-in mechanism to increase modularity, a new 3D segmentation tool, and new computer-aided design (CAD)based solid modeling capabilities. Here, we focus on major changes to the software platform and outline features added in this new release. We also briefly describe our recent experiences using SimVascular in the classroom for bioengineering education.

关键词： patient-specific simulation image-based modeling CFD hemodynamics open-source finite element method biomechanics software

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modeling and animating realistic faces from images

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INTERNATIONAL JOURNAL OF COMPUTER VISION 2002年第2期50卷 143-169页

作者： Pighin, F Szeliski, R Salesin, DH Univ So Calif Inst Creat Technol Los Angeles CA 90089 USA Microsoft Res Redmond WA USA Univ Washington Dept Comp Sci Seattle WA 98195 USA

We present a new set of techniques for modeling and animating realistic faces from photographs and videos. Given a set of face photographs taken simultaneously, our modeling technique allows the interactive recovery of a textured 3D face model. By repeating this process for several facial expressions, we acquire a set of face models that can be linearly combined to express a wide range of expressions. Given a video sequence, this linear face model can be used to estimate the face position, orientation, and facial expression at each frame. We illustrate these techniques on several datasets and demonstrate robust estimations of detailed face geometry and motion.

关键词： facial animation performance-driven animation image-based modeling model-based tracking analysis by synthesis

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Challenges in modeling Hemodynamics in Cerebral Aneurysms Related to Arteriovenous Malformations

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CARDIOVASCULAR ENGINEERING AND TECHNOLOGY 2022年第5期13卷 673-684页

作者： Boster, Kimberly A. Stevens Shidhore, Tanmay C. Cohen-Gadol, Aaron A. Christov, Ivan C. Rayz, Vitaliy L. Purdue Univ Sch Mech Engn W Lafayette IN 47907 USA Indiana Univ Sch Med Dept Neurol Surg Indianapolis IN 46202 USA Purdue Univ Weldon Sch Biomed Engn Sch Mech Engn W Lafayette IN 47907 USA

Purpose The significantly higher incidence of aneurysms in patients with arteriovenous malformations (AVMs) suggests a strong hemodynamic relationship between these lesions. The presence of an AVM alters hemodynamics in proximal vessels by drastically changing the distal resistance, thus affecting intra-aneurysmal flow. This study discusses the challenges associated with patient-specific modeling of aneurysms in the presence of AVMs. Methods We explore how the presence of a generic distal AVM affects upstream aneurysms by examining the relationship between distal resistance and aneurysmal wall shear stress using physiologically realistic estimates for the influence of the AVM on hemodynamics. Using image-based computational models of aneurysms and surrounding vasculature, aneurysmal wall-shear stress is calculated for a range of distal resistances corresponding to the presence of AVMs of various sizes and compared with a control case representing the absence of an AVM. Results In the patient cases considered, the alteration in aneurysmal wall shear stress due to the presence of an AVM is considerable, as much as 19 times the base case wall shear stress. Furthermore, the relationship between aneurysmal wall shear stress and distal resistance is shown to be highly geometry-dependent and nonlinear. In most cases, the range of physiologically realistic possibilities for AVM-related distal resistance are so large that patient-specific flow measurements are necessary for meaningful predictions of wall shear stress. Conclusions The presented work offers insight on the impact of distal AVMs on aneurysmal wall shear stress using physiologically realistic computational models. Patient-specific modeling of hemodynamics in aneurysms and associated AVMs has great potential for understanding lesion pathogenesis, surgical planning, and assessing the effect of treatment of one lesion relative to another. However, we show that modeling approaches cannot usually meaningfully quantify

关键词： image-based modeling Cerebrovascular hemodynamics Arteriovenous malformations Cerebral aneurysms

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Interactive 3D content modeling for Digital Earth

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VISUAL COMPUTER 2016年第10期32卷 1293-1309页

作者： Samavati, Faramarz Runions, Adam Univ Calgary Dept Comp Sci Calgary AB Canada Univ Calgary Dept Comp Sci Graph Jungle Comp Graph Lab Calgary AB Canada

Digital Earth is a global reference model for integrating, processing and visualizing geospatial datasets. In this reference model, various data-types, including Digital Elevation Models (DEM) and imagery (orthophotos), are universally and openly available for the entire globe. However, 3D content such as detailed terrains with features, man-made structures, 3D water bodies and 3D vegetation are not commonly available in Digital Earth. In this paper, we present an interactive system for the rapid creation and integration of these types of 3D content to augment Digital Earth. The inputs to our system include available data sources, such as DEM and imagery information depicting landscapes and urban environments. The proposed system employs sketch-based and image-assisted tools to support interactive creation of textured 3D content. For adding terrain features visible in orthophotos, and also the basin of water bodies, we use a multiscale least square surface fitting to generate an adaptive triangular subdivision. For modeling forests and vegetation, we use image-based techniques and take advantage of visible regions and colors of forests in orthophotos. For 3D man-made structures, starting from a single photograph, we provide a simple image-assisted sketching tool to extract these objects, correct for perspective distortion and place them into desired locations.

关键词： Digital Earth Computer graphics Interactive modeling Sketch-based modeling Subdivision surfaces image-based modeling

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image Analysis and modeling in Medical image Computing Recent Developments and Advances

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METHODS OF INFORMATION IN MEDICINE 2012年第5期51卷 395-397页

作者： Handels, H. Deserno, T. M. Meinzer, H. -P. Tolxdorff, T. Med Univ Lubeck Inst Med Informat D-23538 Lubeck Germany Aachen Univ Technol RWTH Dept Med Informat Aachen Germany German Canc Res Ctr Dept Med & Biol Informat Heidelberg Germany Charite Inst Med Informat D-13353 Berlin Germany

Background: Medical image computing is of growing importance in medical diagnostics and image-guided therapy. Nowadays, image analysis systems integrating advanced image computing methods are used in practice e.g. to extract quantitative image parameters or to support the surgeon during a navigated intervention. However, the grade of automation, accuracy, reproducibility and robustness of medical image computing methods has to be increased to meet the requirements in clinical routine. Objectives: In the focus theme, recent developments and advances in the field of modeling and model-based image analysis are described. The introduction of models in the image analysis process enables improvements of image analysis algorithms in terms of automation, accuracy, reproducibility and robustness. Furthermore, model-based image computing techniques open up new perspectives for prediction of organ changes and risk analysis of patients. Methods: Selected contributions are assembled to present latest advances in the field. The authors were invited to present their recent work and results based on their outstanding contributions to the Conference on Medical image Computing BVM 2011 held at the University of Lubeck, Germany. All manuscripts had to pass a comprehensive peer review. Results: modeling approaches and model-based image analysis methods showing new trends and perspectives in model-based medical image computing are described. Complex models are used in different medical applications and medical images like radiographic images, dual-energy CT images, MR images, diffusion tensor images as well as microscopic images are analyzed. The applications emphasize the high potential and the wide application range of these methods. Conclusions: The use of model-based image analysis methods can improve segmentation quality as well as the accuracy and reproducibility of quantitative image analysis. Furthermore, image-based models enable new insights and can lead to a deeper understand

关键词： Medical image computing image analysis image-based modeling model-based image segmentation image registration

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Fluid Volume modeling from Sparse Multi-view images by Appearance Transfer

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ACM TRANSACTIONS ON GRAPHICS 2015年第4期34卷 1-10页

作者： Okabe, Makoto Dobashi, Yoshinori Anjyo, Ken Onai, Rikio Univ Electrocommun Chofu Tokyo 182 Japan Hokkaido Univ Sapporo Hokkaido 060 Japan OLM Digital Inc Tokyo Japan JST CREST Tokyo Japan

We propose a method of three-dimensional (3D) modeling of volumetric fluid phenomena from sparse multi-view images (e.g., only a single-view input or a pair of front- and side-view inputs). The volume determined from such sparse inputs using previous methods appears blurry and unnatural with novel views;however, our method preserves the appearance of novel viewing angles by transferring the appearance information from input images to novel viewing angles. For appearance information, we use histograms of image intensities and steerable coefficients. We formulate the volume modeling as an energy minimization problem with statistical hard constraints, which is solved using an expectation maximization (EM)-like iterative algorithm. Our algorithm begins with a rough estimate of the initial volume modeled from the input images, followed by an iterative process whereby we first render the images of the current volume with novel viewing angles. Then, we modify the rendered images by transferring the appearance information from the input images, and we thereafter model the improved volume based on the modified images. We iterate these operations until the volume converges. We demonstrate our method successfully provides natural-looking volume sequences of fluids (i.e., fire, smoke, explosions, and a water splash) from sparse multiview videos. To create production-ready fluid animations, we further propose a method of rendering and editing fluids using a commercially available fluid simulator.

关键词： image-based modeling natural phenomena animation volume modeling texture analysis/synthesis single-view modeling

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Using metaballs to modeling and animate clouds from satellite images

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VISUAL COMPUTER 1999年第9期15卷 471-482页

作者： Dobashi, Y Nishita, T Yamashita, H Okita, T Hiroshima City Univ Fac Informat Sci Asaminami Ku Hiroshima 7313194 Japan Univ Tokyo Dept Informat Sci Bunkyo Ku Tokyo 1130033 Japan Hiroshima Univ Fac Engn Higashihiroshima 7398527 Japan

We propose modeling that uses metaballs to create realistic clouds from satellite images. The method is intended for space flight simulators, visualization of the weather information, and simulation of surveys of the earth, The density distribution inside the clouds is defined by a set of metaballs. The parameters (center positions, radii, and density values) are automatically determined so that the synthesized image is similar to the satellite image. We also propose an animation method for clouds generated by a sequence of satellite images taken at a given interval. We give several examples of clouds generated from satellite images of typhoons passing through Japan.

关键词： clouds image-based modeling satellite image metaballs

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Structured Annotations for 2D-to-3D modeling 09

Structured Annotations for 2D-to-3D Modeling

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ACM SIGGRAPH Asia Conference 2009

作者： Gingold, Yotam Igarashi, Takeo Zorin, Denis NYU JST ERATO New York NY 10003 USA

ISBN: (纸本)9781605588582

We present a system for 3D modeling of free-form surfaces from 2D sketches. Our system frees users to create 2D sketches from arbitrary angles using their preferred tool, which may include pencil and paper. A 3D model is created by placing primitives and annotations on the 2D image. Our primitives are based on commonly used sketching conventions and allow users to maintain a single view of the model. This eliminates the frequent view changes inherent to existing 3D modeling tools, both traditional and sketch-based, and enables users to match input to the 2D guide image. Our annotations-same-lengths and angles, alignment, mirror symmetry, and connection curves-allow the user to communicate higher-level semantic information;through them our system builds a consistent model even in cases where the original image is inconsistent. We present the results of a user study comparing our approach to a conventional "sketch-rotate-sketch" workflow.

关键词： user interfaces sketch-based modeling annotations interactive modeling image-based modeling

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