A 2D Mapping Method Based on Virtual Laser Scans for Indoor Robots

The indoor robots are expected to complete metric navigation tasks safely and efficiently in complex environments, which is the essential prerequisite for accomplishing other high-level operation tasks. 2 D occupancy grid maps are sufficient to support the robots in avoiding all obstacles in the environments during navigation. However, the maps based on normal laser scans only reflect a horizontal slice of the environment, which may cause the problem of some obstacles missing or misinterpreting their exact boundaries,thereby threatening the safety and efficiency of robot navigation. This paper presents a 2 D mapping method based on virtual laser scans to provide a more comprehensive representation of obstacles for indoor robot navigation. The resulting maps can accurately represent the top-down projected contours of all obstacles no matter where their vertical positions are. The virtual laser scans are initially generated from raw data of an RGB-D camera based on the filtering, projection, and polar-coordinate scanning. The scans are fed directly to the laser-based simultaneous localization and mapping(SLAM) algorithms to update the current map and robot position. Two auxiliary strategies are proposed to further improve the quality of maps by reducing the impact of the narrow field of view and the blind zone of the RGB-D camera on the observations. In this paper, the improved virtual laser generation method makes the extracted 2 D observations fit the laser-based SLAM algorithms, and two auxiliary strategies are novel ways to improve map quality. The generated maps can reflect the comprehensive obstacle information in indoor environments with good accuracy. The comparative experiments are carried out based on four simulation scenarios and three real-world scenarios to prove the effectiveness of our 2 D mapping method.

A method of key positioning based on laser virtual keyboard

The paper puts forward a method of virtual keyboard key positioning based on infrared laser reflection and image processing technology. In this paper, the positioning principle is introduced first. And the experimental system is established based on image acquisition, image transformation, threshold selection and binarization processing and identification of key placement. Tested in the indoor environment, the method can achieve characters input efficiently and accurately. And the key positioning has high accuracy, validity and reliability. So the method which has a high practical value provides a good theoretical basis for design of virtual keyboard application.

Influence of the virtual photon field on the squeezing properties of an atom laser

This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose-Einstein condensate. It discusses the influences of atomic eigenfrequency, the interaction intensity between the optical field and atoms, parameter of the binomial states field and virtual photon field on the squeezing properties. The results show that two quadrature components of an atom laser can be squeezed periodically. The duration and the degree of squeezing an atom laser have something to do with the atomic eigenfrequency and the parameter of the binomial states field, respectively. The collapse and revival frequency of atom laser fluctuation depends on the interaction intensity between the optical field and atoms. The effect of the virtual photon field deepens the depth of squeezing an atom laser.

VIRTUAL PROCESSING OF LASER SURFACE HARDENING ON AUTOBODY DIES

A new method of collision-free path plan integrated in virtual processing is developed to improve the efficiency of laser surface hardening on dies. The path plan is based on the premise of no collision and the optimization object is the shortest path. The optimization model of collision-free path is built from traveling salesman problem （TSP）. Collision-free path between two machining points is calculated in configuration space （C-Space）. Ant colony optimization （ACO） algorithm is applied to TSP of all the machining points to find the shortest path, which is simulated in virtual environment set up by IGRIP software. Virtual machining time, no-collision report, etc, are put out atter the simulation. An example on autobody die is processed in the virtual platform, the simulation results display that ACO has perfect optimization effect, and the method of virtual processing with integration of collision-free optimal path is practical.

激光诱导击穿光谱(LIBS)分析虚拟仿真实验

虚拟仿真实验作为大型仪器分析实验教学模式的新兴趋势,有效地将虚拟仿真技术与实物仪器教学相结合,最大限度地提升了学生对于大型仪器分析的综合应用能力。本文以激光诱导击穿光谱(LIBS)虚拟仿真实验系统为例,完整地模拟了LIBS系统的样品处理、光谱采集、定性分析和定量分析等实际实验场景,通过虚实结合实验教学模式对实验过程进行实时跟踪与综合考评。该实验有助于提高学生自主探究能力和创新意识,培养具有独立思考与实践能力的拔尖人才。

大跨度钢桁梁桥智能建造技术应用的可行性研究

大跨度钢桁梁桥的构件制造及拼装复杂,采用场内预制组装仍需消耗大量的人力、财力及工期。因此,本文采用BIM桥梁建模、三维激光扫描和虚拟预拼装技术,进行了基于BIM技术的施工方案模拟的可行性研究和基于BIM技术与三维激光扫描方法结合的构件加工质量检测研究,并在此基础上进行了基于BIM技术与三维激光扫描方法结合的虚拟拼装技术研究,探索了大跨度钢桁梁桥智能建造技术应用于指导工程实施的可行性。

三维激光扫描技术在解决工业驱动汽轮机装配干涉问题的应用与研究

详细阐述了三维激光扫描技术在工业驱动汽轮机装配上的应用,对三维激光扫描的关键技术(高精度测量、快速扫描、虚拟装配等)进行了分析研究,提出了通过高效装配仿真技术解决工业驱动汽轮机部套装配干涉问题的方案,探索并总结了一套适合汽轮机部套虚拟装配预防装配干涉的技术。

基于虚幻引擎的红外成像激光对抗模拟系统

为了得到激光对红外成像系统可视化、场景化的干扰效果,采用虚幻引擎搭建了红外成像激光对抗模拟系统。利用虚幻引擎的模型与场景编辑功能构建对抗场景,并模拟红外成像;构建了激光干扰数学模型,以此生成模拟激光干扰光斑,实现了不同距离、不同红外成像视场以及不同激光入射角的对抗模拟,并对干扰前后的图像进行了对比分析。结果表明,当红外成像视场保持不变、干扰距离由3.7 km减小为2.9 km和2 km时,干扰光斑面积在成像中的占比均逐渐增大;当干扰距离保持不变、红外成像视场由8°缩小为6°和4°时,干扰光斑面积在成像中的占比也逐渐增大;当红外成像视场与干扰距离不变,激光入射角度在±4°范围内调整,干扰光斑面积几乎没有变化。该模拟系统能较真实地对红外成像及激光对抗效果进行模拟,可作为红外成像激光对抗效能评估研究的基础工具。

激光雕刻虚拟仿真实验开发研究

将虚拟仿真融入实验教学是教育信息化建设的重要组成部分。分析了虚拟仿真实验教学的重要性,阐述了虚拟仿真融入实验教学的两种常见模式,介绍了虚拟现实在实验教学中的主要展现形式。以激光雕刻实验为例,开发了激光雕刻虚拟仿真实验,搭建了虚拟实验教学场景,仿真了激光雕刻加工过程,建设了线上实验教学平台,简述了虚拟仿真实验的一般开发流程和主要技术手段。实践证明,融入虚拟仿真的实验教学可为改良传统的实验教学模式提供借鉴与参考。

虚拟现实技术下激光三维无障碍空间图像增强算法

与普通空间图像相比,激光三维无障碍空间图像包含信息量更多,给图像的增强算法带来较大难度,为了提高激光三维无障碍空间图像质量,提出虚拟现实技术下激光三维无障碍空间图像增强算法。在虚拟现实技术下,生成激光三维无障碍空间图像,采用双边和引导滤波相结合的方式进行去噪处理,提取图像特征,通过去模糊、变换增强、细节特征增强、颜色增强等步骤,得出激光三维无障碍空间图像的增强处理结果。通过测试实验得出结论:与传统图像增强算法相比,优化设计算法得出增强图像的信噪比和对比度更高,分别提升约49 dB和68 dB,由此证明优化设计算法具有更优的图像增强效果。

基于激光测距仪的智能物联网体感交互感知研究

当前的智能物联网设备在识别用户指令方面存在不足,时常需要用户多次尝试,降低了用户的使用体验和对设备的信任度。为了解决问题,提出了一种基于激光测距仪的智能物联网体感交互感知方法。首先,拟合激光波绘制结果,并利用距离变换算法设定智能物联网的体感交互方式。然后,通过误差传递公式,计算激光测距仪的协方差矩阵,依据此调整参数和测量点。最后,融合激光图像特征,识别操作者的动态指令。实验结果表明,所提方法能够显著提升智能物联网设备对体感指令的采集完整度,正确完成所有体感指令,且平均体感动作类别划分精准度高达97.02%,说明所提方法具有较高的体感交互感知精度。

基于视觉传达技术的激光三维图像虚拟重建方法

为了提升激光三维图像虚拟重建效果,提出了基于视觉传达技术的激光三维图像虚拟重建方法。获取激光三维图像的纹理特征值,采集到激光三维图像,提取激光三维图像重建特征;融合频率域特征和纹理特征,得到激光三维图像多特征数据集以及激光三维图像多特征数据集内坏特征,设计多特征融合的步骤;根据多特征融合结果,得到三维特定激光三维图像模型,实现激光三维图像虚拟重建结果。实验结果证明:该系统可有效解决了激光三维图像重建难题,当遮挡比例为18%时,尺度不变深度误差值与平均角度误差值均达到最大,最大值均未超过设置阈值,本方法结构相似度在90%以上,重建精度较高,可以实现激光三维图像高精度虚拟重建。

融入虚拟仿真的激光雕刻印刷电路板实验教学模式设计

为了解决激光雕刻实验教学实际问题,设计了“虚拟仿真+线上线下混合式”实验教学模式,搭建了相应的实验教学平台,并建立了多层次多维度实验教学评价体系。从教学效果上看,“虚拟仿真+线上线下混合式”实验教学模式不仅有效提升了实验教学目标高阶性,还增强了实验教学内容丰富性,进而提高了实验教学质量。

基于激光视觉的3D舞美虚拟人物影像自动化识别系统

针对3D舞美虚拟人物影像易受到成像条件干扰,导致人物姿态识别误差大的问题,设计基于激光视觉的3D舞美虚拟人物影像自动化识别系统。使用线结构光视觉三维测量装置,采集表演人物的激光视觉图像后,以平行投影的方式,重构3D舞美虚拟人物影像;通过基于谱系聚类的关键姿态轮廓特征提取方法,提取影像中关键姿态轮廓特征,输入基于HCRF的3D舞美虚拟人物影像人体姿态识别模型,计算人体姿态动作类型的条件概率,实现3D舞美虚拟人物影像自动化识别。实验结果表明,该系统对3D舞美虚拟人物影像中,行走、跑步、跳跃、跌倒、身体倾斜五种姿态类型自动化识别后,识别结果的交并比最小值为0.986,识别结果与真实姿态动作类型匹配。

激光点云数据离群点删除下的多视点场景虚拟重构

单纯的激光扫描技术在现实场景虚拟重构时,有效点云数据过少,坐标均衡性较差,混乱坐标较多。为提高虚拟现实重构精度,设计基于激光点云离群点删除的多视点场景虚拟重构方法。提取多视点场景激光点云数据,包括激光数据角点特征提取,以及视觉数据角点特征提取。设置离群阈值,计算三维坐标轴中非离群点数据集所包含的空间长度,设置离群点坐标栅格结构。通过点激光云数据提取值,计算移除离群点前后点云数据之间的平均距离,完成无用数据移除,实现虚拟重构。实验结果可知:移除前后平均距离差距显著,可见离群点的移除对虚拟现实重构技术有明显作用;在使用所提方法得到的虚拟现实重构场景中,可以得到明显的房间轮廓,且大型物体重构影像也十分清晰。

三维激光扫描技术在桥梁合龙中的应用研究

桥梁的分段建造是为了确保施工的质量和安全性,而合龙则是形成完整桥梁的最后一步。为了减少实际合龙过程中的风险,数字化模拟合龙已成为关键步骤。本文以某桥梁建造工程为例,利用三维激光扫描技术描述了桥梁虚拟合龙的整体技术流程,通过分段点云数据建立了三维模型并进行了合龙测试。此项研究突显了三维激光扫描技术在桥梁虚拟合龙设计中的应用潜力。

光波导输入的双通道同步定标虚拟成像相位阵列光谱仪

激光频率梳定标的虚拟成像相位阵列光谱仪有潜力同时实现超高光谱分辨率与波长定标精度,对于天文光谱探测有重要意义。然而,现有的研究工作中,虚拟成像相位阵列光谱仪采用常规的双通道光纤输入模式,在受环境干扰时,两个通道的同步性较差,相对漂移严重,从而降低了光谱仪的重复性定标精度。为解决该问题,提出一种以光波导作为输入器件的双通道虚拟成像相位阵列光谱仪,利用波导通道之间相对稳定的特性,实现更高水平的同步定标精度。通过对不同环境下光谱仪的稳定性进行研究得出,在相似的测试条件下,波导输入的虚拟成像相位阵列光谱仪的重复性定标精度明显优于光纤输入时的定标表现。

V–L decomposition of a novel full-waveform lidar system based on virtual instrument technique

A novel three-dimensional（3D） imaging lidar system which is based on a virtual instrument technique is introduced in this paper. The main characteristics of the system include： the capability of modeling a 3D object in accordance with the actual one by connecting to a geographic information system（GIS）, and building the scene for the lidar experiment including the simulation environment. The simulation environment consists of four parts： laser pulse, atmospheric transport,target interaction, and receiving unit. Besides, the system provides an interface for the on-site experiment. In order to process the full waveform, we adopt the combination of pulse accumulation and wavelet denoising for signal enhancement.We also propose an optimized algorithm for data decomposition： the V-L decomposition method, which combines Vondrak smoothing and laser-template based fitting. Compared with conventional Gaussian decomposition, the new method brings an improvement in both precision and resolution of data decomposition. After applying V-L decomposition to the lidar system, we present the 3D reconstructed model to demonstrate the decomposition method.

脉冲激光沉积过程虚拟仿真实验设计及教学模式探索

脉冲激光沉积(PLD)薄膜制备技术是物理气相沉积技术中先进的工艺和手段之一,也是材料学科实验教学的重要内容,但该实验所需实验仪器精密、操作复杂、耗材昂贵且用量大,严重制约其有效开展。基于此,自主开发设计了PLD过程虚拟仿真实验项目,完整模拟了PLD薄膜制备的工艺流程及关键控制条件,实现虚实结合。通过线上、线下结合的教学模式,实现沉浸式漫游、互动式学习、自主选择练习,达到激发兴趣、提升能力、提高效率的教学目标,有效培养学生的创新意识。

基于三维激光扫描的教学用飞机结构虚拟实践平台构建

依据教育部虚拟仿真实验教学课程的建设要求和航空类人才培养目标,结合飞行器设计与工程本科专业特点,利用三维激光扫描、逆向建模和可视化演示等数字化技术手段,为“飞行器结构设计”“结构维修与适航”等航空专业核心课构建了教学用飞机结构虚拟实践平台,营造了“沉浸式”“虚拟机库”的教学氛围,取得了显著的教学成效,满足了在线教学资源共享、多校区实物教学演示等要求,储备了大量的典型飞机结构数字化案例。