电纺PANI/PEO纳米纤维传感器制备与应用

采用静电纺丝法制备了聚苯胺/聚环氧乙烷（ PANI/PEO）纳米纤维,研究了电压、接收距离对电纺PANI/PEO纳米纤维直径的影响,对电纺参数进行了优化。通过对电纺接收端的控制,制备了平行纳米纤维阵列,实现了纳米纤维的定向排布;通过对电纺射流沉积次数的控制,制备了PANI/PEO纳米单纤维传感器,并对NH3进行了气敏性测试。结果表明：当电纺电压为20 kV且接收距离为20 cm时,获得的PA-NI/PEO纳米纤维直径为105 nm,且形貌较佳,在此优化参数条件下制备的单纤维PANI/PEO纳米传感器在常温下对低浓度的NH3有良好的线性响应输出。     

Electrospinning of hollow and core/sheath nanofibers using a microfluidic manifold

In this article, we describe a microfluidic approach to fabricate hollow and core/sheath nanofibers by electrospinning. Key benefits in using microfluidic devices for nanofiber synthesis include rapid prototyping, ease of fabrication, and the ability to spin multiple fibers in parallel through arrays of individual microchannels. Hollow poly (vinylpyrrolidone) (PVP) + titania (TiO₂) composite and core/sheath polypyrrole (PPy)/PVP nanofibers of the order of 100 and 250 nm, respectively, were successfully fabricated using elastomeric microfluidic devices. Fiber characterization was subsequently carried out using a combination of scanning electron microscopy and transmission electron microscopy.     

3‐D crosstalk and luminance uniformity from angular luminance profiles of multiview autostereoscopic 3‐D displays

Abstract— Autostereoscopic 3‐D display technologies enable a more immersive media experience by adding real depth to the visual content. However, the method used for the creation of a sensation of depth or stereo illusion contains several display design and content‐related issues that need to be carefully considered to maintain sufficient image quality. Conventionally, methods used for 3‐D image‐quality evaluations have been based on subjective testing. Optical measurements, in addition to subjective testing, can be used as an efficient tool for 3‐D display characterization. Objective characterization methods for autostereoscopic displays have been developed. How parameters affecting stereo image quality can be defined and measured, and how their effect on the stereo image quality can be evaluated have been investigated. Developed characterization methods are based on empirically gathered data. In this paper, previously presented methodology for two‐view displays is extended to cover autostereoscopic multiview displays. A distinction between displays where the change in content occurs in clear steps when the user moves in front of the display, and displays where the apparent movement of the objects is more continuous as a function of the head movement is made. Definitions for 3‐D luminance and luminance uniformity, which are equally important, as well as 3‐D crosstalk, which is the dominant factor in the evaluations of the perceived 3‐D image quality, is focused upon.     

Intuitive 3D Maps for MAV Terrain Exploration and Obstacle Avoidance

Recent development showed that Micro Aerial Vehicles (MAVs) are nowadays capable of autonomously take off at one point and land at another using only one single camera as exteroceptive sensor. During the flight and landing phase the MAV and user have, however, little knowledge about the whole terrain and potential obstacles. In this paper we show a new solution for a real-time dense 3D terrain reconstruction. This can be used for efficient unmanned MAV terrain exploration and yields a solid base for standard autonomous obstacle avoidance algorithms and path planners. Our approach is based on a textured 3D mesh on sparse 3D point features of the scene. We use the same feature points to localize and control the vehicle in the 3D space as we do for building the 3D terrain reconstruction mesh. This enables us to reconstruct the terrain without significant additional cost and thus in real-time. Experiments show that the MAV is easily guided through an unknown, GPS denied environment. Obstacles are recognized in the iteratively built 3D terrain reconstruction and are thus well avoided.     

基于虚拟仪器的舵机半实物仿真系统研究

传统舵机控制算法的设计大多是通过数字仿真来实现的,数字仿真过程中舵机执行机构模型的不准确使得仿真结果与实际情况有较大的差距。提出一种基于虚拟仪器的舵机控制半实物仿真系统,该系统利用LabVIEW软件平台开发了舵机执行机构的控制算法仿真模块,并通过D/A设备将控制参数发送给舵机执行机构。结合高速A/D设备对舵机反馈信号进行采集,在软件中实现对舵机控制算法性能的实时分析。试验结果表明,该系统解决了数字仿真中舵机执行机构模型不准确的问题,为舵机开发过程中的控制算法设计仿真提供了更为灵活、高效的方法。     

Parametric editing of clothed 3D avatars

Easy editing of a clothed 3D human avatar is central to many practical applications. However, it is easy to produce implausible, unnatural looking results, since subtle reshaping or pose alteration of avatars requires global consistency and agreement with human anatomy. Here, we present a parametric editing system for a clothed human body, based on use of a revised SCAPE model. We show that the parameters of the model can be estimated directly from a clothed avatar, and that it can be used as a basis for realistic, real-time editing of the clothed avatar mesh via a novel 3D body-aware warping scheme. The avatar can be easily controlled by a few semantically meaningful parameters, 12 biometric attributes controlling body shape, and 17 bones controlling pose. Our experiments demonstrate that our system can interactively produce visually pleasing results.     

Using extension method for health analysis system of a fitness device

This paper used foot-operated fitness equipment, a power generation system and a biomedical measurement system to construct a fitness system for fitness exercise, energy storage and diagnosing the user’s movement conditions. The diagnostic mode is that the rotation speed and output power of pedal-dynamo are converted into the mileage and calorie consumption of the user’s pedaling movement. Second, the biomedical measurement module can diagnose the user’s movement health status timely according to the heartbeat signals and the consumed calories while the user is in exercise. The diagnostic data were integrated using touch tablet PC and LabVIEW software for the image controlled man-machine interface. The user can observe the real-time motion state through the virtual instrument interface. The built-in program can diagnose the health status, and count the total generation and movement process after exercise.     

Optimization of Comb-Driven Devices for Mechanical Testing of Polymeric Nanofibers Subjected to Large Deformations

Comb-driven electrostatic actuators applied to mechanical testing of nanostructures are usually designed by a ldquobrute-forcerdquo approach for maximum electrostatic-force output, which results in limited actuation range. This issue is more prevalent when testing soft nanofibers with large ductility. In this paper, the design considerations for a comb-driven platform for nanoscale mechanical testing of ductile nanofibers subjected to 50%, or larger, inelastic extensions are presented. The optimization carried out aimed at increasing the net-force output by comb drives with clamped-clamped tethers, which also improves on the accuracy in the calculation of the force that is applied onto the nanofiber specimens. At large actuator motions, tethers of low bending stiffness increased the net force applied to a nanofiber and provided better accuracy in the calculation of the applied force. On the contrary, at small actuator motions, the maximum net-force output by the comb drives increased with the axial tether stiffness due to the associated increase in the pull-in-instability voltage. The fabricated surface-micromachined devices enabled experiments with individual electrospun polyacrylonitrile nanofibers at a maximum force of 30 muN and extensions up to 60%. The force output calculated from the voltage input to the electrostatic devices was compared to direct measurements by an independent optical method. [2008-0252]     

Real-time 3D motion capture by monocular vision and virtual rendering

Networked 3D virtual environments allow multiple users to interact over the Internet by means of avatars and to get some feeling of a virtual telepresence. However, avatar control may be tedious. 3D sensors for motion capture systems based on 3D sensors have reached the consumer market, but webcams remain more widespread and cheaper. This work aims at animating a user’s avatar by real-time motion capture using a personal computer and a plain webcam. In a classical model-based approach, we register a 3D articulated upper-body model onto video sequences and propose a number of heuristics to accelerate particle filtering while robustly tracking user motion. Describing the body pose using wrists 3D positions rather than joint angles allows efficient handling of depth ambiguities for probabilistic tracking. We demonstrate experimentally the robustness of our 3D body tracking by real-time monocular vision, even in the case of partial occlusions and motion in the depth direction.     

基于PSoC和DP-PSO-SVM的便携式假肢控制系统

针对三自由度假肢阈值控制方式存在不直观、灵活性差的缺陷，控制效果较好的模式识别控制器存在便携性差、实用性差等问题，提出一种基于PSoC在线模式识别的肌电假肢控制系统设计方案.采用低功耗芯片PSoC作为主控制器，设计了一套便携式四通道sEMG （表面肌电信号）采集系统，采用双群粒子群优化算法改进的支持向量机（DP-PSO-SVM）构建分类识别器，并通过假肢驱动器实现假肢在线模式控制.实验结果表明：采用DP-PSO-SVM算法比采用标准粒子群SVM （PSO-SVM）算法构建的分类器识别精度提高4%，达到96.7%；该控制器对6种动作的在线识别率达到96.3%，且符合实时性要求.     

A Novel Automatic Classification System Based on Hybrid Unsupervised and Supervised Machine Learning for Electrospun Nanofibers

The manufacturing of nanomaterials by the electrospinning process requires accurate and meticulous inspection of related scanning electron microscope (SEM) images of the electrospun nanofiber, to ensure that no structural defects are produced. The presence of anomalies prevents practical application of the electrospun nanofibrous material in nanotechnology. Hence, the automatic monitoring and quality control of nanomaterials is a relevant challenge in the context of Industry 4.0. In this paper, a novel automatic classification system for homogenous (anomaly-free) and non-homogenous (with defects) nanofibers is proposed. The inspection procedure aims at avoiding direct processing of the redundant full SEM image. Specifically, the image to be analyzed is first partitioned into sub-images (nanopatches) that are then used as input to a hybrid unsupervised and supervised machine learning system. In the first step, an autoencoder (AE) is trained with unsupervised learning to generate a code representing the input image with a vector of relevant features. Next, a multilayer perceptron (MLP), trained with supervised learning, uses the extracted features to classify non-homogenous nanofiber (NH-NF) and homogenous nanofiber (H-NF) patches. The resulting novel AE-MLP system is shown to outperform other standard machine learning models and other recent state-of-the-art techniques, reporting accuracy rate up to 92.5%. In addition, the proposed approach leads to model complexity reduction with respect to other deep learning strategies such as convolutional neural networks (CNN). The encouraging performance achieved in this benchmark study can stimulate the application of the proposed scheme in other challenging industrial manufacturing tasks.      

TransCAIP: A Live 3D TV System Using a Camera Array and an Integral Photography Display with Interactive Control of Viewing Parameters

The system described in this paper provides a real-time 3D visual experience by using an array of 64 video cameras and an integral photography display with 60 viewing directions. The live 3D scene in front of the camera array is reproduced by the full-color, full-parallax autostereoscopic display with interactive control of viewing parameters. The main technical challenge is fast and flexible conversion of the data from the 64 multicamera images to the integral photography format. Based on image-based rendering techniques, our conversion method first renders 60 novel images corresponding to the viewing directions of the display, and then arranges the rendered pixels to produce an integral photography image. For real-time processing on a single PC, all the conversion processes are implemented on a GPU with GPGPU techniques. The conversion method also allows a user to interactively control viewing parameters of the displayed image for reproducing the dynamic 3D scene with desirable parameters. This control is performed as a software process, without reconfiguring the hardware system, by changing the rendering parameters such as the convergence point of the rendering cameras and the interval between the viewpoints of the rendering cameras.     

Streaming of Complex 3D Scenes for Remote Walkthroughs

We describe a new 3D scene streaming approach for remote walkthroughs. In a remote walkthrough, a user on a client machine interactively navigates through a scene that resides on a remote server. Our approach allows a user to walk through a remote 3D scene, without ever having to download the entire scene from the server. Our algorithm achieves this by selectively transmitting only small parts of the scene and lower quality representations of objects, based on the user's viewing parameters and the available connection bandwidth. An online optimization algorithm selects which object representations to send, based on the integral of a benefit measure along the predicted path of movement. The rendering quality at the client depends on the available bandwidth, but practical navigation of the scene is possible even when bandwidth is low.     

Computerized control system and interface for flexible micromanipulator control

Micro- and nanomanipulators are essential for a broad range of applications requiring precise micro- and nanoscopic spatial control such as those in micromanufacturing and single cell analysis. These manipulators are often manually controlled using an attached joystick and can be difficult for operators to use efficiently. This paper describes a system developed in MATLAB to control a well-known, commercial micromanipulator in a user friendly and versatile manner through a graphical user interface (GUI). The control system and interface allows several types of flexible movement controls in three-axis, Cartesian space, including single movements, multiple queued movements, and mouse-following continuous movements. The system uses image processing for closed loop feedback to ensure precise and accurate control over the movement of the manipulator’s end effector. The system can be used on any electronic device capable of running the free MATLAB Runtime Environment (MRE) and the system is extensible to simultaneously control other instruments capable of serial communication.     

六轴陀螺仪MPU6050的虚拟3D模型角度控制

基于六轴陀螺仪MPU6050和集成WiFi芯片的Arduino设计,搭建了对Unreal Engine4(虚幻引擎)中3D模型进行角度姿态控制的硬件设备,该设备可嵌入到实际物体与虚拟3D模型进行实时交互.空间角度数据由DMP姿态解算器分析处理,MPU6050与Arduino等用串口通信,将数据打包,通过UDP协议将数据上传至Unreal Engine4(虚幻引擎)独立线程处理.测试结果表明,硬件设备与3D模型可以实现实时角度姿态控制,以低成本的投入提高了用户的体验感与沉浸感.     

3维卡通水与物体交互作用的动画建模

为了生成水与物体交互作用的卡通动画,提出一个混合式的3维卡通水模型。先构造出复杂的各种卡通水波模型,然后在2维工作区上对它们进行结构上的组合并映射到3维水面上进行绘制;障碍物在3维水面上的覆盖区域被检测出来之后,将其逆映射到2维工作区并在工作区内实现流水波形和障碍物所在区域的碰撞检测,根据碰撞检测结果触发障碍物附近的激起浪花波形。该方法的特点在于既表现了卡通流水与障碍物的碰撞,又保持了手工绘画的艺术感。此外,用户还可以方便地对波形的形态、位置、速度等进行设置与调控。系统利用GPU（图形处理器）硬件处理能力实现了对3维卡通水与物体交互的实时绘制。     

自动日志功能的实时控制Java3D机械手仿真

主要介绍了一个既可以作为Java应用程序在单机运行,又可以作为Java Applet在网络环境中使用的基于Java3D的机械手仿真系统.鉴于仿真系统中,存在的因由鼠标、键盘控制而带来的操作缺乏灵活性,从而很难满足实时控制要求,以及缺少自动建立仿真操作日志的有效方法等问题.通过介绍如何利用Jinput技术接入带有操纵杆的输入设备,以及如何利用数据映射机制建立操作日志,不仅为上述问题提供了解决办法,而且将其实际运用到机械手仿真系统中.同时,还使用了碰撞检测技术实现了仿真机械手对虚拟小球的实时抓取功能.     

View-projection animation for 3D occlusion management

Inter-object occlusion is inherent to 3D environments and is one of the challenges of using 3D instead of 2D computer graphics for visualization. Based on an analysis of this effect, we present an interaction technique for view-projection animation that reduces inter-object occlusion in 3D environments without modifying the geometrical properties of the objects themselves. The technique allows for smooth on-demand animation between parallel and perspective projection modes as well as online manipulation of view parameters, enabling the user to quickly and easily adapt the view to reduce occlusion. A user study indicates that the technique provides many of the occlusion reduction benefits of traditional camera movement, but without the need to actually change the viewpoint. We have also implemented a prototype of the technique in the Blender 3D modeler.     

Interactive Construction and Animation of Layered Elastically Deformable Characters

An interactive system is described for creating and animating deformable 3D characters. By using a hybrid layered model of kinematic and physics-based components together with an immersive 3D direct manipulation interface, it is possible to quickly construct characters that deform naturally when animated and whose behavior can be controlled interactively using intuitive parameters. In this layered construction technique, called the elastic surface layer model, a simulated elastically deformable skin surface is wrapped around a kinematic articulated figure. Unlike previous layered models, the skin is free to slide along the underlying surface layers constrained by geometric constraints which push the surface out and spring forces which pull the surface in to the underlying layers. By tuning the parameters of the physics-based model, a variety of surface shapes and behaviors can be obtained such as more realistic-looking skin deformation at the joints, skin sliding over muscles, and dynamic effects such as squash-and-stretch and follow-through. Since the elastic model derives all of its input forces from the underlying articulated figure, the animator may specify all of the physical properties of the character once, during the initial character design process, after which a complete animation sequence can be created using a traditional skeleton animation technique. Character construction and animation are done using a 3D user interface based on two-handed manipulation registered with head-tracked stereo viewing. In our configuration, a six degree-of-freedom head-tracker and CrystalEyes shutter glasses are used to display stereo images on a workstation monitor that dynamically follow the user head motion. 3D virtual objects can be made to appear at a fixed location in physical space which the user may view from different angles by moving his head. To construct 3D animated characters, the user interacts with the simulated environment using both hands simultaneously: the left hand, controlling a Spaceball, is used for 3D navigation and object movement, while the right hand, holding a 3D mouse, is used to manipulate through a virtual tool metaphor the objects appearing in front of the screen. Hand-eye coordination is made possible by registering virtual space to physical space, allowing a variety of complex 3D tasks necessary for constructing 3D animated characters to be performed more easily and more rapidly than is possible using traditional interactive techniques.     

碳黑/聚乙烯醇电纺复合纤维的制备与气敏特性研究

通过碳黑(CB)/聚乙烯醇(PVA)混合溶液的电纺,制备了掺纳米CB的PVA复合纤维,用扫描电镜(SEM)观察了它的形貌。CB/PVA复合纳米纤维的形貌取决于混合物中CB的含量。随CB含量的增加,CB颗粒在纤维中的分布逐渐变得均匀;最佳CB/PVA的质量比为3∶10;继续增加CB含量,CB颗粒聚合成团析出,杂乱分布于PVA纤维中。乙醇蒸气测试表明:质量比为3∶10的CB/PVA纤维具有灵敏度高、响应恢复快等特点。