基于II三维重建的facet-braiding现象分析

三维全景图像技术(Integral Imaging,简称II)是一种能够记录和显示全真三维场景的图像技术。该技术采用微透镜阵列记录空间场景,空间任意一点的深度信息只需通过一次成像即可直接获得。Facet braiding是三维全景图像中一种很重要的视觉现象,该现象造成图像失真,影响了图像的观看效果。Ref. 6中Martine} Cuenca从单个元素图像的角度对该现象进行了分析,现从三维重建的角度对该现象的出现与否进行对比验证。先用光学软件模拟深度优先、参考平面在无穷远处的传统II成像系统,然后在该模拟系统中进行对比实验,结果并未出现Ref. 6中提到的facet braiding现象。该结果对II的视角分析、物体的精确三维重建及空间分辫率分析具有重要意义。     

记录分辨率对II三维重建分辨率的影响

三维全景图像技术(Integral Imaging,简称II)是一种能够记录和显示全真三维场景的图像技术.分辨率低一直是限制该技术发展的最重要因素之一,而其中记录分辨率对三维重建分辨率的影响尤其突出,但目前这方面的研究较少且与实际不符.在深度优先的II系统中分析研究记录分辨率对II三维重建分辨率的影响,推导出记录分辨率与深度的关系,并以实验验证所得结果.对II成像系统优化参数设计、物体空间分辨率分析及未来三维电视的数据处理具有重要意义.     

基于序列图像的三维重构

提出了一种基于序列图像的三维重构方法。在相机标定的基础上,利用两幅图像间的匹配关系得到一个初始的三维模型,然后利用剩余图像与初始模型间的匹配关系,采用反投影映射的方法计算出剩余图像的外方位元素。最后经过稠密匹配、三角剖分和纹理渲染得到物体的三维模型。实验结果表明,相机标定精度较高的情况下,采用该算法能够得到较低失真的三维模型。     

基于异步延时法的颗粒动态轨迹测量方法

为了获取河流中泥沙污染物颗粒的动态运动轨迹详情,减少泥沙沉降对河道的污染,提出了一种基于异步延时法和光场相机相结合的颗粒动态轨迹测量方法,通过相机在长曝光时间内记录的颗粒运动轨迹,实现颗粒运动状态的观测。首先采用普通相机搭建了二维测量系统进行颗粒运动轨迹的测量,该方法无需复杂的图像处理算法,通过图像的简单叠加就能实现颗粒运动轨迹测量,测量系统的误差为0.28%,为后期采用光场相机实现颗粒轨迹的三维测量奠定了基础。     

一个基于深度图像的三维模型检索算法

三维模型检索是现在的研究热点,提出一种基于深度图像的三维模型检索算法。对三维模型进行规范化处理,采用基于正交投影的方法计算三维模型在其包围立方体的六个面上的深度图像;提取深度图像的边界方向直方图和Zernike矩特征;利用特征距离度量进行三维模型检索,并采用相关反馈技术实现权值的调整,得到用户最满意的目标检索模型。对比实验表明,该算法避免了传统视觉图像丢失三维模型空间信息的缺点,有效地提高了检索的精确性和鲁棒性。     

基于三维全景图的校园漫游系统王绪宛,雷蕾

虚拟现实是利用电脑模拟产生一个三维空间的虚拟世界,让使用者如同身历其境,而三维全景图是虚拟现实中一种重要的场景表示方法,生成三维全景图最简单的方法是直接使用全景相机等工具拍摄全景图,由于相机设备价格昂贵,限制了普遍使用;基于图像拼接技术对图像序列进行处理后生成全景图的低成本方法。该方法在南阳理工学院虚拟校园系统中使用,实现了虚拟校园的实景漫游,大大降低了成本。     

一种新型红外立体视觉定位系统研究

为实现视觉目标可靠快速三维定位,设计了一种新型的基于DSP的嵌入式主动双目红外视觉系统。与普通的红外相机不同,该系统采用常规CCD相机加红外滤光片的新方法采集红外图像,通过红外滤光后的低噪声图像可以转化为低噪声二值化图像,以此提高目标定位的准确度。提出了离散化遍历视觉目标搜索算法,通过离散控制两个相机的旋转和倾斜运动,实现视觉目标快速主动遍历搜索。实验证明,该系统目标三维定位有良好的鲁棒性。     

一个相关反馈三维模型深度图像检索算法

基于图像的三维模型检索比形状特征和拓扑结构特征具有更易于实现且检索效果好等优点,但现有基于图像的三维模型检索方法存在一些问题,如没有考虑三维深度信息、所提特征不能全部表达三维模型信息且不能实现用户交互操作等。对此提出一种基于深度图像的三维模型相关反馈检索算法:首先提取三维模型深度图像边界方向直方图和Zernike矩特征;然后利用特征距离度量进行三维模型检索,并采用相关反馈技术实现分类器的构造和模型的标注;最后利用调整好的权值分类器进行检索和标注。实验表明,该算法实现了三维模型的相关反馈检索和标注,提高了检索的精确性,并增强了系统的实用性,为进一步进行语义检索打下基础。     

基于机器视觉的输电线跨越距离测量方法研究

主要研究了一种基于机器视觉的输电线跨越距离测量方法.设计了一套双目立体视觉测量系统,可以实时监测输电线路跨越距离.该系统通过双目相机实时采集标有特征标记点的输电线图像,采用颜色分割检测方法实现左右图像的立体匹配,计算出特征标记点的空间坐标,从而实现跨越输电线的三维重构,并基于跨越输电线的三维模型计算出跨越距离的大小.实验数据表明,该方法的测量精度达3％以内,满足实际要求,验证了该方法的可行性.     

基于双目视觉的板材平面测量研究

针对传统人工测量板材尺寸精度较低、工作量大、易导致板材表面受损等局限,基于双目视觉技术设计了一种板材尺寸视觉测量系统;通过双目相机采集棋盘格图像,采用MATLAB进行相机标定和图像校正,拍摄左右图像并通过半全局立体匹配算法(SGM,semi global matching)进行特征点立体匹配,重建出目标三维点云模型;为提高目标特征点坐标获取的准确性,提出基于HARRIS的亚像素检测方法;采用区域生长算法结合膨胀和腐蚀操作提取板材表面轮廓,根据三角测量原理计算出板材轮廓上各点的三维坐标从而实现板材的尺寸测量,并进行点云重建增强三维展示效果;实践结果表明亚像素检测方法在角点提取上存在优势,在实际板材测量应用中实现了高精度尺寸测量,满足了工业测量需求。     

Fabrication of a micro-tip array mold using a micro-lens mask with proximity printing

In this study, a mold for a micro-tip array is fabricated using a microlens array mask with proximity exposure. The micro-tip array uses a microlens array mask with geometrical optics. Light passing through a microlens is focused at the focal points. There is microlens on the mask and the pattern that results from the light passing through the mask is directly projected onto the photoresist surface. A concave profile is developed using a positive photoresist and the remaining photoresist microstructures are formed after the development process. By changing the distance between the mask and the photoresist and the radius of curvature of the microlens, various tip shapes can be fabricated. The exposure gap is calculated using the microlens array mask and the geometry of the mold of micro-tip array is established using the irradiance absorption maps for the different levels. These methods respectively use the model of the positive photoresist and optical software. When electroforming a metallic micro-tip copy of the patterned photoresist, masters are created. The metal micro-tip array is used membrane probe card.     

A roller embossing process for rapid fabrication of microlens arrays on glass substrates

This paper reports an innovative technique for rapid fabrication of polymeric microlens arrays based on UV roller embossing process. In this method, a thin flat mold is fabricated by electroforming of nickel against a microlens master. The thin Ni mold with microlens cavities is then wrapped onto cylinder to form the roller. During rolling operation, the roller pressing and dragging the UV-curable photopolymer layer on the glass substrate through the rolling zone, the microlens array is formed. At the same time, the microlens array is cured by the UV light radiation while traveling through the rolling zone. The technique can be developed to an effective roll-to-roll process at room temperature and with low pressure. In this study, a roller embossing facility with UV exposure capacity has been designed, constructed and tested. Under the proper processing conditions, the 100×100 arrays of polymeric microlens, with a diameter of 100 μm, a pitch of 200 μm and a sag height of 21 μm can be successfully fabricated.     

Double‐viewing‐zone integral imaging 3D display without crosstalk based on a tilted barrier array

We propose an integral imaging (II) three‐dimensional (3D) display using a tilted barrier array and a stagger microlens array. The tilted barrier array consists of two orthogonally polarized sheets. In the stagger microlens array, the center of the microlens has p/2 shift with the elemental image along the horizontal direction, where p is the pitch of the microlens. The proposed II 3D display produces two different viewing zones and each of them is almost equal to that of the conventional II 3D display, and it has no crosstalk. We verify the feasibility of the proposed II 3D display in the simulation results.     

New production method of convex microlens arrays for integrated fluorescence microfluidic detection systems

A new method for producing microlens array with large sag heights is proposed for integrated fluorescence microfluidic detection systems. Three steps in this production technique are included for concave microlens array formations to be integrated into microfluidic systems. First, using the photoresist SU-8 to produce hexagonal microchannel array is required. Second, UV curable glue is injected into the hexagonal microchannel array. Third, the surplus glue is rotated by a spinner at high velocity and exposed to a UV lamp to harden the glue. The micro concave lens molds are then finished and ready to produce convex microlens in poly methsiloxane (PDMS) material. This convex microlens in PDMS can be used for detecting fluorescence in microfluidic channels because a convex microlens plays the light convergence role for optical fiber detection.     

基于CompactRIO的多通道阵列数据采集系统实现

实时性和可靠性是影响多通道阵列数据采集系统的重要因素.详细阐述了基于CompactRIO(简称CRIO)的多通道阵列数据采集系统的软硬件设计.通过采用CRIO技术实现了多个通道的高速切换和数据采集,对多通道的阵列数据进行了分析处理.阵列数据三维显示图实时准确地反映了阵列数据的变化规律.实验结果表明系统稳定可靠,通道一致性良好,可在100 Hz采样频率下采集更新640路通道数据.     

New production method of convex microlens arrays for integrated fluorescence microfluidic detection systems

A new method for producing microlens array with large sag heights is proposed for integrated fluorescence microfluidic detection systems. Three steps in this production technique are included for concave microlens array formations to be integrated into microfluidic systems. First, using the photoresist SU-8 to produce hexagonal microchannel array is required. Second, UV curable glue is injected into the hexagonal microchannel array. Third, the surplus glue is rotated by a spinner at high velocity and exposed to a UV lamp to harden the glue. The micro concave lens molds are then finished and ready to produce convex microlens in poly methsiloxane (PDMS) material. This convex microlens in PDMS can be used for detecting fluorescence in microfluidic channels because a convex microlens plays the light convergence role for optical fiber detection.

     

一种基于3维全景图像技术的深度测量方法

3维全景图像技术是一种能够记录和显示全真3维场景的图像技术。该技术采用微透镜阵列记录空间场景，空间任意一点的深度信息只需通过一次成像即可直接获得。本文研究采用全景图像技术直接获取物体空间信息的方法。此方法首先从全景图像中抽提视图。视图是通过抽提全景图像中对应于每个微透镜下同一局部位置的点人工合成的。每幅视图包含了全景图像中对原来的物空间场景按照某一特定方向的平行投影记录信息。接下来通过分析全景图像的光学成像过程。推导了用来描述物体深度信息和其在对应的视图间的视差关系的深度方程。从而得出空间任一点的深度可以通过其在对应视图间的视差来求得。最后，通过运用全景图像测量火柴盒的厚度的实例，验证了这一方法的可行性。其结果一方面可用于全景图像的数据处理本身，另一方面可望为开发新型的深度测量工具提供理论依据。     

Microfabrication of pre-aligned fiber bundle couplers using ultraviolet lithography of SU-8

This paper describes the design, microfabrication and testing of a pre-aligned array of fiber couplers using direct UV-lithography of SU-8. The fiber coupler array includes an out-of-plane refractive microlens array and two fiberport collimator arrays. With the optical axis of the pixels parallel to the substrate, each pixel of the microlens array can be pre-aligned with the corresponding pixels of the fiberport collimator array as defined by the lithography mask design. This out-of-plane polymer 3D microlens array is pre-aligned with the fiber collimator arrays with no additional adjustment and assembly required, therefore, it helps to dramatically reduce the running cost and improve the alignment quality and coupling efficiency. In addition, the experimental results for the fiber couplers are also presented and analyzed.     

New high fill-factor dual-curvature microlens array fabrication using UV proximity printing

A new high fill-factor dual-curvature microlens array fabrication method using lithographic proximity printing process is reported. The proposed technology utilizes UV proximity printing by controlling a printing gap between the mask and substrate. The designed microlens array pattern with high density can produce a high fill-factor dual-curvature microlens array in photoresist. Because the UV light diffraction deflects away from the aperture edges and produces exposure in photoresist material outside the aperture edges, this method can precisely control the geometric profile of a high fill factor dual-curvature microlens array. The experimental results showed that the dual-curvature micro-lens array can be formed automatically in photoresist when the printing gap ranged from 360 to 600 μm. The gapless dual-curvature microlens array will be used to enhance the luminance uniformity for light-emitting diodes (LEDs).