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Continuous optimization of interior carving in 3D fabrication

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Frontiers of Computer Science 2017年第2期11卷 332-346页

作者： Yue XIE Ye YUAN Xiang CHE Changxi ZHENG Kun ZHOU State Key lab of cad&CG Zhejiang University Hangzhou 310058 China Columbia University New York NY 10027 USA

In this paper we propose an optimization frame- work for interior carving of 3D fabricated shapes. Interior carving is an important technique widely used in industrial and artistic designs to achieve functional purposes by hollow- ing interior shapes in objects. We formulate such functional purpose as the objective function of an optimization prob- lem whose solution indicates the optimal interior shape. In contrast to previous volumetric methods, we directly repre- sent the boundary of the interior shape as a triangular mesh. We use Eulerian semiderivative to relate the time derivative of the object function to a virtual velocity field and iteratively evolve the interior shape guided by the velocity field with sur- face tracking. In each iteration, we compute the velocity field guaranteeing the decrease of objective function by solving a linear programming problem. We demonstrate this general framework in a novel application of designing objects float- hag in fluid and two previously investigated applications, and print various optimized objects to verify its effectiveness.

关键词： computer graphics 3D printing interior carving shape optimization Eulerian semiderivative

ECharts: A declarative framework for rapid construction of web-based visualization

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Visual Informatics 2018年第2期2卷 136-146页

作者： Deqing Li Honghui Mei Yi Shen Shuang Su Wenli Zhang Junting Wang Ming Zu Wei Chen Baidu Inc. China State Key lab of cad&CG Zhejiang UniversityChina

While there have been a dozen of authoring systems and programming toolkits for visual design and development,users who do not have programming skills,such as data analysts or interface designers,still may feel cumbersome to efficiently implement a web-based *** this paper,we present ECharts,an open-sourced,web-based,cross-platform framework that supports the rapid construction of interactive *** motivation is driven by three goals:easy-touse,rich built-in interactions,and high *** kernel of ECharts is a suite of declarative visual design language that customizes built-in chart *** underlying streaming architecture,together with a high-performance graphics renderer based on HTML5 canvas,enables the high expandability and performance of *** report the design,implementation,and applications of ECharts with a diverse variety of *** compare the utility and performance of ECharts with ***,HighCharts,and *** of the experiments demonstrate the efficiency and scalability of our *** the first release in June 2013,ECharts has iterated 63 versions,and attracted over 22,000 star counts and over 1700 related projects in the *** is regarded as a leading visualization development tool in the world,and ranks the third in the GitHub visualization tab.

关键词： Information visualization Web-based visualization

Electro-mechanical response of functionally graded beams with imperfectly integrated surface piezoelectric layers

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Science China(Physics,Mechanics & Astronomy) 2006年第5期49卷 513-525页

作者： YAN Wei1 & CHEN Weiqiu1,2 1. Department of Civil Engineering, Zhejiang University, Hangzhou 310027, China 2. State Key lab of cad & CG, Zhejiang University, Hangzhou 310027, China Department of Civil Engineering Zhejiang University Hangzhou China State Key lab of cad & CG Zhejiang University Hangzhou China

The time-dependent behavior of a simply-supported functionally graded beam bonded with piezoelectric sensors and actuators is studied using the state-space method. The creep behavior of bonding adhesives between piezoelectric layers and beam is characterized by a Kelvin-Voigt viscoelastic model, which is practical in a high temperature circumstance. Both the host elastic functionally graded beam and the piezoelectric layers are orthotropic and in a state of plane stress, with the former being inhomogeneous along the thickness direction. A laminate model is employed to approximate the host beam. Moreover, the coupling effect between the elastic deformation and electric field in piezoelectric layers is considered. Results indicate that the viscoelastic property of interfacial adhesives has a significant effect on the function of bonded actuators and sensors with time elapsing.

关键词： functionally graded beam piezoelectric layers Kelvin-Voigt model state-space method

Line clipping against polygonal window algorithm based on the multiple virtual boxes rejecting

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2005年第B8期6卷 100-107页

作者：王进陆国栋彭群生吴煊晖 State Key lab. of cad&CG Zhejiang University Department of Electrical and Computer Engineering National University of Singapore

This paper presents a new algorithm for line clipping against a polygonal window by exploiting the local relationship between each line segment and the polygon. Firstly, a minimal enclosing box （MEB） of the polygon is adopted to reject the invisible line segments located outside the MEB. Secondly, a 45° rotated box is used to encode the endpoint of the line segment, and then reject a portion of the invisible segments crossing polygon comers. Finally, instead of encoding the endpoints of all line segments with respect to the polygonal window, each vertex of the polygon is encoded, taking the line segment to be clipped as reference. For efficient encoding of the polygon vertices, a new concept, termed with slope adaptive virtual box, is introduced regarding each line segment. Such a box can not only conveniently reject all totally invisible lines lying outside the MEB conveniently, but also precisely identify the edges of the polygon with which the line segment potentially intersects. With the summation of the vertex codes, it can be verified whether the line segment is separated from or potentially intersects the polygon window. Based on the product of the codes of adjacent vertices, singular cases of intersection can be solved accurately. Experimental results demonstrate the efficiency and stability of the new algorithm.

关键词： Polygon vertex encoding Adaptive virtual box Line segment rejection Line segment intersection Line clipping

Erroneous pixel prediction for semantic image segmentation

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Computational Visual Media 2022年第1期8卷 165-175页

作者： Lixue Gong Yiqun Zhang Yunke Zhang Yin Yang Weiwei Xu State Key lab of cad&CG Zhejiang UniversityHangzhou 310058China School of Computing Clemson University South Carolina29634USA

We consider semantic image *** method is inspired by Bayesian deep learning which improves image segmentation accuracy by modeling the uncertainty of the network *** contrast to uncertainty,our method directly learns to predict the erroneous pixels of a segmentation network,which is modeled as a binary classification *** can speed up training comparing to the Monte Carlo integration often used in Bayesian deep *** also allows us to train a branch to correct the labels of erroneous *** method consists of three stages:(i)predict pixel-wise error probability of the initial result,(ii)redetermine new labels for pixels with high error probability,and(iii)fuse the initial result and the redetermined result with respect to the error *** formulate the error-pixel prediction problem as a classification task and employ an error-prediction branch in the network to predict pixel-wise error *** also introduce a detail branch to focus the training process on the erroneous *** have experimentally validated our method on the Cityscapes and ADE20K *** model can be easily added to various advanced segmentation networks to improve their *** Deeplabv3+as an example,our network can achieve 82.88%of mloU on Cityscapes testing dataset and 45.73%on ADE20K validation dataset,improving corresponding Deeplabv3+results by 0.74%and 0.13%respectively.

关键词： erroneous pixel prediction image segmentation deep learning

A Survey of Macroscopic Brain Network Visualization Technology

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Chinese Journal of Electronics 2018年第5期27卷 889-899页

作者： CHEN Weifeng SHI Lei CHEN Wei School of Information Zhejiang University of Finance & Economics State Key lab of Computer Science Institute of SoftwareChinese Academy of Sciences State Key lab of cad&CG Zhejiang University

Brain science, as an important branch of Neuroscience, is a discipline that studies the structure and function of brain nervous system of human and other mammals. With the invention of new technologies such as brain imaging, light microscopes and brain electromagnetics,brain science is gradually unraveling the mysteries of human emotion, intelligence and behavior. In this wave, data visualization punctuates the landmark advances in brain science since its beginning. This survey reviews the recent literature on brain network visualization(aka connectome)from the fields of both connectomics and visualization. In particular, we focus on the macroscopic-level brain network visualization techniques, that reveal the structural and functional connectivity of the whole brain, in comparison to microsopic-level neuronal connectivities. We also discuss the interactive visualization tools currently available for viewing the brain networks. Finally, we conclude with a number of ongoing challenges in macroscopic brain network visualization.

关键词： Brain network Connectomics Visualization

A level set based segmentation approach for point-sampled surfaces

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第4期8卷 575-585页

作者： MIAO Yong-wei FENG Jie-qing ZHENG Guo-xian PENG Qun-sheng State Key lab. of cad ＆ CG Zhejiang University Hangzhou 310027 China College of Science Zhejiang University of Technology Hangzhou 310032 China

Segmenting a complex 3D surface model into some visually meaningful sub-parts is one of the fundamental problems in digital geometry processing. In this paper, a novel segmentation approach of point-sampled surfaces is proposed, which is based on the level set evolution scheme. To segment the model so as to align the patch boundaries with high curvature zones, the driven speed function for the zero level set inside narrow band is defined by the extended curvature field, which approaches zero speed as the propagating front approaches high curvature zone. The effectiveness of the proposed approach is demonstrated by our ex- perimental results. Furthermore, two applications of model segmentation are illustrated, such as piecewise parameterization and local editing for point-sampled geometry.

关键词： Point-samoled surfaces Segmentation Level set method Extended curvature field

Exploratory study of logistics service quality scale based on online shopping malls

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第6期8卷 926-931页

作者： FENG Yi-xiong ZHENG Bing TAN Jian-rong State Key lab. of cad ＆ CG Zhejiang University Hangzhou 310027 China College of Economics ＆ Management Dalian University Dalian 116622 China

Online shopping has already become the new mode that a lot of customers try to adopt. At the same time, the online shopping could not be successfully completed without logistics service. Logistics service quality (LSQ) has significant impact on revenue and profitability. This paper presents the issue from the perspective of the customer, and explores the initial factors of LSQ based on the online shopping through in-depth interview and the Delphi method. The survey uses a standard 7-point Likert-type scale to measure the LSQ. Empirical research results are shown in detail to confirm seven LSQ dimensions with Chinese characteristics, including timeliness quality, personal contact quality, order quality, order discrepancy handling, order condition and convenience. Statistical analyses of the investigation were conducted to test the reliability and validity of the LSQ evaluation model.

关键词： Online shopping Logistics service Logistics service quality (LSQ) Dimensions of LSQ

Stepwise approach for view synthesis

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第8期8卷 1218-1226页

作者： CHAI Deng-feng PENG Qun-sheng State Key lab of cad and CG Zhejiang University Hangzhou 310027 China Institute of Spatial Information Technique Zhejiang University Hangzhou 310027 China

This paper presents some techniques for synthesizing novel view for a virtual viewpoint from two given views cap-tured at different viewpoints to achieve both high quality and high efficiency. The whole process consists of three passes. The first pass recovers depth map. We formulate it as pixel labelling and propose a bisection approach to solve it. It is accomplished in log2n(n is the number of depth levels) steps,each of which involves a single graph cut computation. The second pass detects occluded pixels and reasons about their depth. It fits a foreground depth curve and a background depth curve using depth of nearby fore-ground and background pixels,and then distinguishes foreground and background pixels by minimizing a global energy,which involves only one graph cut computation. The third pass finds for each pixel in the novel view the corresponding pixels in the input views and computes its color. The whole process involves only a small number of graph cut computations,therefore it is efficient. And,visual artifacts in the synthesized view can be removed successfully by correcting depth of the occluded pixels. Experimental results demonstrate that both high quality and high efficiency are achieved by the proposed techniques.

关键词： View synthesis Occlusion Graph cut