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《光学学报》2016,(8)
为了保证工业机器人磨抛的加工质量,利用激光扫描技术对机器人夹持工件的形状误差以及装夹误差进行测量和评估,包括点云数据的获取和去噪。采用条纹式激光扫描仪配合直线匀速运动对机器人末端夹持工件进行扫描,通过调节测量和运动参数,获取近似网格点云。为了去除点云中存在的大尺度噪点,在K近邻均值滤波(KNNMF)算法基础上,提出了基于局部均值的K近邻均值滤波(LMKMF)算法对偏大的数据点进行局部预先滤波,并建立相关数学模型。以峰值信噪比作为评价标准,以实际测量点云样本为测试对象进行去噪测试。结果表明,相比标准的KNNMF算法,结合LMKMF预先滤波的KNNMF算法在30%噪点密度下去噪能力提升了53.78%,证实了其在高密度噪点下具有更好的去噪能力和特征保持能力。 相似文献
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在先进制造中要求对加工的部组件进行在线质量检测,条纹投影三维测量技术因符合在线、非接触的要求而被采用。然而,金属材质表面反射率差异较大会导致拍摄结构光图像过曝和欠曝光,这会造成最终测量数据的缺失或出错。针对该问题,以直接测量得到的不完整点云数据和由计算机辅助设计(CAD)得到的元件设计数据进行迭代最近点(ICP)点云配准,进而得到相机坐标系下的被测物体估算面形的点云数据。将该数据作为预估面形,结合系统标定参数,可建立投影与成像间同名点的图像强度对应关系。利用相机对待测元件上每一点的光强成像响应曲线计算出投影灰度范围和最低投影灰度。最后,利用生成的非等值系数投影光栅进行高反光元件的三维形貌测量。实验结果表明,所提方法在不改变测量系统结构参数和不增加测量系统结构复杂性的情况下,可以更完整地实现高反光元件的三维面形测量。 相似文献
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为了实现对危化品仓储堆垛安全距离的实时监测和预警,采用由激光测距、旋转云台、编码器等组成的激光扫描监控阵列对垛距进行安全监测。针对激光测距扫描点云数据中异常噪声的问题,采用差值去噪算法。该算法是将扫描得到的激光测距数据点按角度值进行从小到大排序后,相邻两点的距离值依次取差值,然后对距离差值与预设阈值进行比较,滤掉噪点数据。针对几种不同尺寸和形状的障碍物进行了实验研究,结果表明差值去噪方差值明显小于加权二乘、Savitzky-Golay等拟合算法,该算法不仅能有效去除扫描点云数据中的异常噪声,同时较另外两个算法,数据完整性和可靠性更高。 相似文献
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通过光栅投影法可以获取物体的三维点云数据,但是对于形貌复杂的被测物体,由于测量方式本身含有的一定缺陷,会导致所获取的点云数据出现孔洞区域,从而对后续处理造成影响。结合已有的从运动中恢复结构(SFM)算法,提出一种新的点云孔洞修补方法。首先,利用光栅投影法中得到的二维相位信息来提取三维点云孔洞区域的边界点;接着,将SFM获取的点云数据集与光栅投影法所采集的点云数据集进行配准,并提取出信息补充点;最后,在添加了补充点的点云数据集上,利用径向基函数计算曲面方程,修补孔洞。实验结果证明了该算法的稳健性,能较为有效地恢复复杂物体的表面信息。 相似文献
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由于从一个彩色图像中可以提取多个条纹,复合条纹投影技术在三维测量领域得到了广泛的研究和应用。为了覆盖所有的光谱范围,投影和成像系统颜色通道间存在着串扰,从而改变了条纹的形状,最终影响三维数据测量的精度。综述了彩色复合条纹投影三维测量系统中颜色通道间串扰的补偿方法。针对彩色条纹投影系统中相机和投影仪颜色通道间的串扰问题,分析了其形成原因。对彩色条纹投影三维测量系统的串扰消除方法进行了分类和总结,并具体比较了各种方法对串扰消除的效果。所综述的方法对选择合适的串扰消除方法、提高彩色复合结构光投影三维测量系统的精度具有重要的应用价值。 相似文献
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通过对三维激光扫描技术在铁路罐车中的应用研究,对扫描过程中发现的点云残缺及噪点问题进行研究分析,提出一种快速有效点云优化处理方法,新方法包括sp-H点云预处理和EtiG建模优化。验证试验表明,采用新的点云优化处理方法可以在较短时间内将扫描点云进行去噪及残缺修补,并能够快速高效进行模型重建,提升了不同工况环境下扫描点云的适用性,提高了扫描工作效率和准确度,铁路罐车容积测量结果的相对扩展不确定度达到2.4×10-3,为铁路罐车容积扫描最高准确度等级,为三维激光扫描相关技术的发展提供一定借鉴。 相似文献
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Svetlana Lipnitskaya Karim Mynbaev Lidiya Nikulina Vladimir Kramnik Vladislav Bougrov Alexey Kovsh Maxim Odnoblyudov Alexey Romanov 《Optical Review》2014,21(5):655-658
A research has been carried out on the optimization of the shape of encapsulating cover to minimize optical losses in light-emitting modules fabricated with the “chip-on-board” (COB) technology. Optical properties of the components of a typical COB were taken into account including those of the substrate, light-emitting chips, encapsulating material and phosphor particles. Light losses were analyzed for various types of encapsulant surface structuring in an attempt to design an optical element with maximum light extraction efficiency. Calculations were complemented with experimental measurements. The results of the research showed that structuring the surface of the encapsulant can enhance light extraction by 10 to 15% for the material without phosphor particles and by 10 to 14% for the material with phosphor particles. 相似文献
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The need for purely laboratory-based light pseudoscalar particles searches has been emphasized many times in the literature, since astrophysical bounds on these particles rely on several assumptions to calculate the flux produced in stellar plasmas. In this Letter we study the use of light from synchrotron accelerators as a source for a photon regeneration experiment also know as “light shining through a wall”. Such an experiment can significantly improve present limits on the pseudoscalar particle mass and the pseudoscalar–photon coupling constant obtained from laser experiments. This is possible even using a small number of powerful magnets (B∼10 T), due to the large incident photon flux. On the other hand, the use of a broadband incident photon-beam instead of infrared or optical lasers allows a significant improvement in the mass reach of the experiment (it is possible to test masses up to 0.01 eV without a drop in sensitivity). Large, but still feasible, configurations can explore in a quite model-independent way a large part of the parameter space examined by solar searches and HB stars in globular clusters. Additionally, the proposal may be useful for testing string motivated effective theories containing light and weakly interacting particles. 相似文献
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《Optik》2014,125(16):4505-4507
We present our experimental demonstration of controlling waveform of a signal pulse by using two beams of continuous wave (CW) generated by stimulated Brillouin scattering (SBS) in optical fibers with different frequencies. Waveform of the signal pulse is modulated in an “all-optical” way according to total input power. This method is only suitable for light pulse with nanosecond width. We provide a new method for controlling light with light. 相似文献
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关于探照灯照射的光斑速度 总被引:1,自引:1,他引:0
光速(真空中)是自然界物体运动或信息及能量传递的极限,如果不注意这个条件,一般地谈速度,那么,找寻超光速的现象并不是难事.有些教科书上时常以探照灯光斑移动的速度来阐述这种超光速现象,演算得到光斑移动的速度为v=hωcos2θ.本文指出,此结果是错的!对正确结果做的定量计算表明:光斑速度虽仍然能超光速,但正确结果的超光速条件远比错误结果的超光速复杂,而且物理含义也更加丰富. 相似文献
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Vincent Tombelaine Erik Vater Benjamin Dietzek Jürgen Popp Hartmut Bartelt Raphaël Jamier 《Optics Communications》2011,284(7):1970-1974
Supercontinuum fiber light sources with their extremely wide wavelength spectrum can provide new options for achieving specific wavelength distributions in a very flexible way. Two concepts for the combination of such supercontinuum light sources with a spectrally dispersive optical system and an interactive filter for modulating the light spectrum are discussed. These concepts provide the possibility to achieve laser-like light sources with an almost arbitrary shape of the spectrum, great flexibility in interactive tuning of the spectral properties and covering wavelengths from UV to the infrared range. 相似文献
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A two-level medium, described by the Maxwell-Bloch system, is engraved by establishing a standing cavity wave with a linearly polarized electromagnetic field that drives the medium on both ends. A light pulse, polarized along the other direction, then scatters the medium and couples to the cavity standing wave by means of the population inversion density variations. We demonstrate that control of the applied amplitudes of the grating field allows one to stop the light pulse and to make it move backward (eventually to drive it freely). A simplified limit model of the Maxwell-Bloch system with variable boundary driving is obtained as a discrete nonlinear Schr?dinger equation with tunable external potential. It reproduces qualitatively the dynamics of the driven light pulse. 相似文献
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P. Chmela 《Czechoslovak Journal of Physics》1973,23(9):884-887
The process of second harmonic frequency generation in a chaotic (Gaussian) light on the basis of a simple quantum-mechanical model is studied in this work. It is shown that the process of second harmonic frequency generation in the chaotic light is quicker than that in the coherent light with the Poisson distribution of photon number. 相似文献