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Smooth Triaxial Weaving with Naturally Curved Ribbons

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Physical Review Letters 2021年第10期127卷 104301-104301页

作者： Changyeob Baek Alison G. Martin Samuel Poincloux Tian Chen Pedro M. Reis Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Flexible Structures Laboratory Institute of Mechanical Engineering École Polytechnique Fédérale de Lausanne (EPFL) Lausanne 1015 Switzerland Fivizzano Italy Computer Graphics and Geometry Laboratory School of Computer and Communication Sciences École Polytechnique Fédérale de Lausanne (EPFL) Lausanne 1015 Switzerland

Triaxial weaving is a handicraft technique that has long been used to create curved structures using initially straight and flat ribbons. Weavers typically introduce discrete topological defects to produce nonzero Gaussian curvature, albeit with faceted surfaces. We demonstrate that, by tuning the in-plane curvature of the ribbons, the integrated Gaussian curvature of the weave can be varied continuously, which is not feasible using traditional techniques. Further, we reveal that the shape of the physical unit cells is dictated solely by the in-plane geometry of the ribbons, not elasticity. Finally, we leverage the geometry-driven nature of triaxial weaving to design a set of ribbon profiles to weave smooth spherical, ellipsoidal, and toroidal structures.

关键词： Elasticity Topological defects Crystal structures Thin films Finite-element method Geometry Laser techniques

Experimental realization of phonon demultiplexing in three-dimensions

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arXiv 2020年

作者： Bilal, Osama R. Yee, Chern Hwee Rys, Jan Schumacher, Christian Daraio, Chiara Department of Mechanical engineering University of Connecticut Storrs United States Department of Mechanical and Process Engineering ETH Zürich Zürich8092 Switzerland Computer Graphics Laboratory ETH Zürich Zürich8092 Switzerland Division of Engineering and Applied Science California Institute of Technology PasadenaCA91125 United States

Phononic metamaterials enabled the realization of many acoustic components analogous to their electronic counterparts, such as transistors, logic gates and calculators. A key component among these is the demultiplexer, a device that receives multiple signals and sorts them based on their frequencies into separate channels. Previous experimental realizations of acoustic and elastic multiplexers have employed plates with pillars or holes to demultiplex frequencies. However, existing realizations are confined to two-dimensions, which can limit potential acoustic or elastic circuit design. Here we show the first experimental realization of a three-dimensional, four channel phononic demultiplexer. Our design methodology is based on bundles of pass-bands within a large band gap that can easily be tuned for multi-channel frequency demultiplexing. The proposed design can be utilized in acoustic and elastic information processing, nondestructive evaluation and communication applications among others. Copyright © 2020, The Authors. All rights reserved.

关键词： Demultiplexing

Apple Vision Pro for Healthcare: "The Ultimate Display"? Entering the Wonderland of Precision Medicine

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arXiv 2023年

作者： Egger, Jan Gsaxner, Christina Chen, Xiaojun Bian, Jiang Kleesiek, Jens Puladi, Behrus Girardetstraße 2 Essen45131 Germany Hufelandstraße 55 Essen45147 Germany Hufelandstraße 55 Essen45147 Germany Department of Oral and Maxillofacial Surgery University Hospital RWTH Aachen Pauwelsstraße 30 Aachen52074 Germany Institute of Computer Graphics and Vision Graz University of Technology Inffeldgasse 16/II Graz8010 Austria Institute of Biomedical Manufacturing and Life Quality Engineering State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University Dongchuan Road 800 Minhang District Shanghai200240 China Institute of Medical Robotics Shanghai Jiao Tong University Dongchuan Road 800 Minhang District Shanghai200240 China Health Outcomes & Biomedical Informatics College of Medicine University of Florida GainesvilleFL32610 United States Partner Site Essen Hufelandstraße 55 Essen45147 Germany Department of Physics TU Dortmund University August-Schmidt-Str. 4 Dortmund44227 Germany Institute of Medical Informatics University Hospital RWTH Aachen Pauwelsstraße 30 Aachen52074 Germany

At the Worldwide Developers Conference (WWDC) in June 2023, Apple introduced the Vision Pro. The Vision Pro is a Mixed Reality (MR) headset, more specifically it is a Virtual Reality (VR) device with an additional Video See-Through (VST) capability. The VST capability turns the Vision Pro also into an Augmented Reality (AR) device. The AR feature is enabled by streaming the real world via cameras to the (VR) screens in front of the user’s eyes. This is of course not unique and similar to other devices, like the Varjo XR-3. Nevertheless, the Vision Pro has some interesting features, like an inside-out screen that can show the headset wearers’ eyes to "outsiders" or a button on the top, called "Digital Crown", that allows you to seamlessly blend digital content with your physical space by turning it. In addition, it is untethered, except for the cable to the battery, which makes the headset more agile, compared to the Varjo XR-3. This could actually come closer to the "Ultimate Display", which Ivan Sutherland had already sketched in 1965. Not available to the public yet, like the Ultimate Display, we want to take a look into the crystal ball in this perspective to see if it can overcome some clinical challenges that - especially - AR still faces in the medical domain, but also go beyond and discuss if the Vision Pro could support clinicians in essential tasks to spend more time with their patients. © 2023, CC BY.

关键词： Augmented reality

IRIS: Interactive real-time feedback image segmentation with deep learning

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IRIS: Interactive real-time feedback image segmentation with...

Medical Imaging 2020: Biomedical Applications in Molecular, Structural, and Functional Imaging

作者： Pepe, Antonio Schussnig, Richard Li, Jianning Gsaxner, Christina Chen, Xiaojun Fries, Thomas-Peter Egger, Jan Stanford University School of Medicine Department of Radiology 300 Pasteur Dr StanfordCA United States Graz University of Technology Institute of Computer Graphics and Vision Inffeldgasse 16c/II GrazA-8010 Austria Computer Algorithms for Medicine Laboratory GrazA-8010 Austria Graz University of Technology Institute of Structural Analysis Lessingstraße 25/II GrazA-8010 Austria Medical University of Graz Department of Oral and Maxillofacial Surgery Auenbruggerplatz 5/1 GrazA-8036 Austria Shanghai Jiao Tong University School of Mechanical Engineering 800 Dong Chuan Road Shanghai200240 China

ISBN: (纸本)9781510634015

Volumetric examinations of the aorta are nowadays of crucial importance for the management of critical pathologies such as aortic dissection, aortic aneurism, and other pathologies, which affect the morphology of the artery. These examinations usually begin with the acquisition of a Computed Tomography Angiography (CTA) scan from the patient, which is later on postprocessed to reconstruct the 3D geometry of the aorta. The first postprocessing step is referred to as segmentation. Different algorithms have been suggested for the segmentation of the aorta;including interactive methods, as well as fully automatic methods. Interactive methods need to be fine-tuned on each single CTA scan and result in longer duration of the process, whereas fully automatic methods require the possession of a large amount of labeled training data. In this work, we introduce a hybrid approach by combining a deep learning method with a consolidated interaction technique. In particular, we trained a 2D and a 3D U-Net on a limited number of patches extracted from 25 labeled CTA scans. Afterwards, we use an interactive approach, which consists in defining a region of interest (ROI) by just placing a seed point. This seed point is later used as the center of a 2D or 3D patch to be fed to the 2D or 3D U-Net, respectively. Due to the low content variation of these patches, this method allows to correctly segment the ROIs without the need for parameter tuning for each dataset and with a smaller training dataset, requiring the same minimal interaction as state-of-the-art interactive methods. Later on, the new segmented CTA scans can be further used to train a convolutional network for a fully automatic approach. © 2020 SPIE

关键词： Angiography

Digital interface brain computer interaction method based on icon control 11th

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Digital interface brain computer interaction method based on...

11th International Conference on Augmented Cognition, AC 2017, held as part of the 19th International Conference on Human-computer Interaction, HCI 2017

作者： Niu, Yafeng Xue, Chengqi Wang, Haiyan Tang, Wenzhe Zhang, Xinyu Jin, Tao Chen, Yingjie Victor School of Mechanical Engineering Southeast University Nanjing211189 China Science and Technology on Electro-Optic Control Laboratory Luoyang471023 China Mechanical and Electrical Engineering Institute China University of Petroleum Qingdao266580 China Department of Computer Graphics Technology Purdue University West LafayetteIN47907 United States

In order to explore the icon controlled digital interface for brain-computer interaction, we use Event-Related Potential technology, first of all, collect the icons from various digital interfaces, use the image processing software to process the icon images, the method comprises the following steps: communication between EEG and test computer, EEG experiment, off-line analysis of the original signal, time domain and frequency domain feature extraction of the group average EEG signal, microprocessor processing, and obtain the user computer function control command of the icon picture, then extract time domain and frequency domain characteristics of target icon picture EEG signal, and calculate the similarity between them, finally realize the triggering of control instruction of the target icon picture. This method can effectively realize icon brain-computer control of the digital interface, and provide the important reference for other elements to interact with the digital interface brain-computer interaction. © Springer International Publishing AG 2017.

关键词： Time domain analysis

Clinical evaluation of semi-automatic opensource algorithmic software segmentation of the mandibular bone: Practical feasibility and assessment of a new course of action

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arXiv 2018年

作者： Wallner, Jürgen Hochegger, Kerstin Chen, Xiaojun Mischak, Irene Reinbacher, Knut Pau, Mauro Zrnc, Tomislav Schwenzer-Zimmerer, Katja Zemann, Wolfgang Schmalstieg, Dieter Egger, Jan Department of Oral & Maxillofacial Surgery Medical University of Graz Auenbruggerplatz 5/1 Graz Austria Laboratory Graz Austria Institute for Computer Graphics and Vision Graz University of Technology Inffeldgasse 16c/II Graz Austria School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China Department of Dental Medicine and Oral Health Medical University of Graz Billrothgasse 4 Graz Austria BioTechMed-Graz Krenngasse 37/1 Graz Austria

Introduction: computer assisted technologies based on algorithmic software segmentation are an increasing topic of interest in complex surgical cases. However-due to functional instability, time consuming software processes, personnel resources or licensed-based financial costs many segmentation processes are often outsourced from clinical centers to third parties and the industry. Therefore, the aim of this trial was to assess the practical feasibility of an easy available, functional stable and licensed-free segmentation approach to be used in the clinical practice. Material and methods: In this retrospective, randomized, controlled trail the accuracy and accordance of the opensource based segmentation algorithm GrowCut was assessed through the comparison to the manually generated ground truth of the same anatomy using 10 CT lower jaw data-sets from the clinical routine. Assessment parameters were the segmentation time, the volume, the voxel number, the Dice Score and the Hausdorff distance. Results: Overall semi-automatic GrowCut segmentation times were about one minute. Mean Dice Score values of over 85% and Hausdorff Distances below 33.5 voxel could be achieved between the algorithmic GrowCut-based segmentations and the manual generated ground truth schemes. Statistical differences between the assessment parameters were not significant (p0.94) for any of the comparison made between the two groups. Discussion: Complete functional stable and time saving segmentations with high accuracy and high positive correlation could be performed by the presented interactive open-source based approach. In the cranio-maxillofacial complex the used method could represent an algorithmic alternative for image-based segmentation in the clinical practice for e.g. surgical treatment planning or visualization of postoperative results and offers several advantages. Due to an open-source basis the used method could be further developed by other groups or specialists. Systematic compari

关键词： Geometry

Development of a computer-aided design software for dental splint in orthognathic surgery

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arXiv 2017年

作者： Chen, Xiaojun Li, Xing Xu, Lu Sun, Yi Politis, Constantinus Egger, Jan Institute of Biomedical Manufacturing and Life Quality Engineering State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China OMFS IMPATH Research Group Department of Imaging and Pathology Faculty of Medicine KU Leuven Leuven Belgium Department of Oral and Maxillofacial Surgery University Hospitals Leuven Leuven Belgium Faculty of Computer Science and Biomedical Engineering Institute for Computer Graphics and Vision Graz University of Technology Graz Austria BioTechMed-Graz Graz Austria

In the orthognathic surgery, dental splints are important and necessary to help the surgeon reposition the maxilla or mandible. However, the traditional methods of manual design of dental splints are difficult and time-consuming. The research on computer-aided design software for dental splints is rarely reported. Our purpose is to develop a novel special software named EasySplint to design the dental splints conveniently and efficiently. The design can be divided into two steps, which are the generation of initial splint base and the Boolean operation between it and the maxilla-mandibular model. The initial splint base is formed by ruled surfaces reconstructed using the manually picked points. Then, a method to accomplish Boolean operation based on the distance filed of two meshes is proposed. The interference elimination can be conducted on the basis of marching cubes algorithm and Boolean operation. The accuracy of the dental splint can be guaranteed since the original mesh is utilized to form the result surface. Using EasySplint, the dental splints can be designed in about 10 minutes and saved as a stereo lithography (STL) file for 3D printing in clinical applications. Three phantom experiments were conducted and the efficiency of our method was demonstrated. Copyright © 2017, The Authors. All rights reserved.

关键词： computer software

Guided filter for adaptive persistence of ultrasound images

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ICIC Express Letters, Part B: Applications 2013年第6期4卷 1597-1602页

作者： Guo, Dequan Yang, Hongyu Yin, Hao Liu, Dong Chyuan Zhang, Zhijie Key Laboratory of Fundamental Synthetic Vision Graphics and Image Science for National Defense Sichuan University No. 24 South Section 1 Yihuan Road Chengdu 610065 China Department of Mechanical Engineering Neijiang Vocational and Technical College No. 42 Dongtong Road Neijiang 641100 China College of Computer Science Sichuan University No. 24 South Section 1 Yihuan Road Chengdu 610065 China

Medical ultrasonic images often suffer from the electronics noise and speckle artifact, which degrade lesion detectability and increase the likelihood of misdiagnosis. In this paper, a legible and comprehensive method for ultrasonic image is proposed and it can be effective to suppress the noise and improve the images quality. Persistence technology based on temporal multi-frames is utilized to smooth the electronics noise and even lower speckle artifact. To reduce computing complexity, a sum table method and conjugate direction search approaches are applied to speed up estimation of motion vectors. Then, the guided image filter strategy is used to enhance the contrast and detail resolution for the processed image by persistence. The experimental results show that the proposed method is better in quantitative and qualitative perfomance, and enhances the ultrasound image in contrast with existing methods. © 2013 ICIC International.

关键词： Motion estimation

Detail-preserving axial deformation using curve pairs

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Detail-preserving axial deformation using curve pairs

International Conference on Shape Modeling and Applications

作者： Wen-Bing Ge Gang Xu Kin-Chuen Hui Guo-Ping Wang The key lab on machine perception and intelligence of MOE Peking University Beijing China CAD Laboratory Department of Mechanical and Automation Engineering Chinese University of Hong Kong Sha Tin Hong Kong China Galaad I.N.R.I.A. Sophia Antipolis France College of Computer Hangzhou Dianzi University Hangzhou China

Traditional axial deformation is simple and intuitive for users to modify the shape of objects. However, unexpected twist of the object may be obtained. The use of a curve-pair allows the local coordinate frame to be controlled intuitively. However, some important geometric details may be lost and changed in the deformation process. In this paper, we present a detail-preserving axial deformation algorithm based on Laplacian coordinates. Instead of embedding the absolute coordinates into deformation space in traditional axial deformation, we transform the Laplacian coordinates at each vertex according to the transformation of local frames at the closest points on the axial curve. Then the deformed mesh is reconstructed by solving a linear system that describes the reconstruction of the local details in least squares sense. By associating a complex 3D object to a curve-pair, the object can be stretched, bend, twisted intuitively through manipulating the curve-pair, and can also be edited by means of view-dependent sketching. This method combines the advantages of axial deformation and Laplacian mesh editing. Experimental results are presented to show the effectiveness of the proposed method.

关键词： Laplace equations Deformable models Solid modeling Automatic generation control Animation Shape control Laboratories Automation Machine intelligence Educational institutions