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基于Imageware的多视点云拼合技术研究和应用 总被引:1,自引:0,他引:1
逆向工程技术应用中,由于物体的几何形状复杂,测量仪器不能一次完成整个表面的测量工作,需要从多个角度实现对物体表面的完整测量。为了得到完整的数据模型,必须进行数据拼接处理,其目的是通过在两片或多片数据点云(点集)中找出正确的排列关系,使它们能够拼合成一片完整的数据点云。本文以固定球法从不同角度进行多次测量获得多视点云,利用Imageware逆向软件的数据对齐技术实现其多视点云拼合并完成模型重构。 相似文献
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逆向工程中基于标签的点云数据采集与处理 总被引:1,自引:0,他引:1
针对光学扫描仪采集点云数据的特点,以犁体曲面为研究对象,引入圆形标签作为扫描时的识别点及多视拼接的基准点,经合理规划后获取点云数据。从噪声去除、多视拼接、数据平滑与精简等方面讨论了点云数据预处理方法,重点研究基于标签点的多视拼接,提出了人机交互模式下多视点云数据统一方法,实例表明拼接误差可控制在0.05 mm之内,运行时间可缩短30 s左右。并利用逆向工程软件Im ageware完成了犁体曲面的构建,为探索逆向工程在农机产品设计制造中的应用提供借鉴。 相似文献
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在分析了多视数据产生的原因及其不同的数据采集方法,给出了解决多视数据对齐问题的方法。并根据三基准点对齐的原理,采用合适的对齐方法,通过变换坐标从而达到数据对齐定位的目的。本文介绍了目前在逆向工程中常用的几种数据对齐方法。 相似文献
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在逆向工程技术应用中,经常需要得到物体内、外表面几何形状的完整数据.测量仪器往往不便于在同一定位状态(同一坐标系)下完成整个内、外表面的测量工作.为了得到完整数据模型,常用的方法是采用多视拼合技术.本文首先讨论了对齐拼接的算法,然后根据此原理,提出粘贴带有孔的薄壁塑料片的新方法,在不同的定位状态下对物体内、外表面进行多... 相似文献
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K.H. Lee S.K. Lee S.-M. Kim 《The International Journal of Advanced Manufacturing Technology》2002,19(6):426-431
In this paper, a universal fixture for 3D laser scanning is presented. In order to reconstruct the surface or CAD model from
the scanned data of an existing part, it is necessary to integrate the point data from several views of an object into a common
reference frame. When the registration is implemented with a feature-based method using tooling balls, the reference coordinate
system is established by several common tooling balls from different point clouds. The laser scanner is often used to acquire
the surface information of the part, but is limited in its measuring direction, which is fixed only along the z-axis. A universal fixture using several joints and an adjustable tooling ball holder is designed considering the convenience
of the part set-up and the accuracy of the registration. The location of the tooling balls can be arranged to avoid the occlusion
of the part and to minimise the registration error. The universal fixture was applied to a wrap-around part having freeform
surfaces to demonstrate the effectiveness of the proposed design. 相似文献
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改进Demons算法的非刚性医学图像配准 总被引:4,自引:0,他引:4
非刚性配准是医学图像处理的一个重要的研究方向。基于光流场模型的Demons算法由于仅依赖图像灰度梯度使图像变形,当缺乏梯度信息时图像的变形方向不能确定,因而容易造成误配准,且该算法只适合于单模态图像配准。本文针对最大互信息配准方法在多模态刚性配准中的成功应用,提出了一种可用于多模态图像配准的改进Demons算法。该方法在原有驱动图像变形力的基础上,增加两幅图像间互信息对当前变换的梯度作为附加力作用,使浮动图像向两图像间互信息增大的方向变形,正确地配准图像。为避免陷入局部极值并提高算法的运行速度,该方法在多分辨率策略下实现。使用单模态、多模态图像分别进行实验来验证此算法,并与原始Demons算法进行比较,实验表明,该方法能够快速地产生准确的配准变换。 相似文献
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针对道路场景下多智能网联汽车协同感知问题,本文提出一种基于点云稀疏语义特征的智能网联汽车协同感知配准算法。所提算法旨在通过点云集成配准扩展智能网联汽车感知范围,进而实现智能网联汽车协同感知。首先,在道路语义特征基础上进行几何特征提取进而得到点云稀疏语义特征。其次,计算道路语义特征点云间的角度偏差以提供配准初值,并将点云语义信息作为配准约束条件实现全局语义集成配准。实验表明所提算法有效扩大了多智能网联汽车协同感知范围,提高了多点云集成配准的精度与鲁棒性。与当前主流算法JRMPC相比,本文所提算法配准精度提高了2.45%。 相似文献
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Registration of serial sections of mouse liver cell nuclei 总被引:7,自引:0,他引:7
Image registration of biological tissue is essential for 3D reconstruction, which is important for visualizing and quantifying the 3D relationships between internal structures of an object. The biological role of DNA organization, which is an extremely complex 3D architecture within the cell nucleus, has come into focus since it has become clear that the chromatin structure in itself functions as a regulator of DNA. Thus, 3D reconstruction of cell nuclei based on consecutive series of high-resolution ultrathin slices may provide new information about the chromatin structure and its organizational changes during carcinogenesis. This work focuses mainly on the problem of registering successive serial transmission electron micrographs of ultrathin sections of mouse liver cell nuclei to analyse the 3D chromatin structure. A five-step semiautomatic interactive registration method is proposed. The first two steps of the procedure correct the rotation and translation components by using the phase correlation. The third, fourth and fifth steps correct the global distortion, employing a point mapping method based on different ways of selecting the control points. In step three, the control points were automatically computed by phase correlating corresponding subimages of the reference and sensed image. A semiautomatic method is used in the fourth step to select the control points, i.e. an automated method for computing the centre of mass of manually identified anatomical structures in neighbouring slices. For the sections which could not be properly corrected by the four steps, a final step is introduced, where control points are manually selected in the reference and sensed images. An algorithm is proposed to examine the spatial distribution of selected control points. Four sets of serial sections of mouse liver cell nuclei, each with approximately 100 sections, are registered by the proposed method and also registered manually for the comparison of registration accuracy. Artificial X–Z and Z–Y sections of registered series were visually compared for the smoothness of the nuclear membrane. To quantify the registration accuracy and the extent of registration, the correlation coefficient (C) and the overlap index (C0) were computed over the registered structure of interest. In addition to the visual comparison and the comparison of C and C0, the registered serial sets were compared by 3D GLCM-based texture features in the Z direction. The results demonstrate that the proposed semiautomatic registration technique achieved accurate results comparable to the manual registration. The proposed registration method relies only on the operator for rough pinpointing of cellular structures. Therefore, it should provide better reproducibility, and allow the user to operate the system faster and in a more relaxed manner than in a manual registration. 相似文献
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一种基于最小均方差理论的散斑图像亚像素配准算法,是按线性估计理论推导目标函数的解析解,利用刚体位移模型和散斑图像仿真模型生成5组40帧长斑图像序列,分别在无噪声干扰和加性高斯噪声干扰下对算法进行实验验证。实验结果表明,在无噪声干扰下,图像序列的位移轨迹具有较好的线性度,且系统误差和随机误差较小。在不同噪声水平干扰下,当信噪比为10dB时,该算法失效;而当信噪比不低于20dB时,噪声对配准结果的影响随着信噪比的增加将逐渐减弱。 相似文献
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