1 西南科技大学信息工程学院，四川 绵阳 621010
2 特殊环境机器人技术四川省重点实验室，四川 绵阳 621010
针对交联聚乙烯（XLPE）电缆接头反应力锥参数测量问题，本文结合XLPE电缆接头结构特征与三维点云处理提出了一种XLPE电缆接头反应力锥参数测量算法。该算法先对点云进行去噪及坐标摆正预处理；之后根据XLPE电缆接头的结构特征，得到反应力锥及其相邻区域的目标点云；然后使用依据目标点云中各点与坐标轴的夹角信息及高度信息提出的点云空间划分方法，实现对目标点云的条状划分及块元划分；接着根据条状点云上块元法向量的轴线夹角及改进的凹凸性准则求得各条状点云不同区域的局部点云；在此基础上，使用随机采样一致性（RANSAC）算法及拉格朗日乘数法求取相邻区域拟合平面的相交线，再根据条状点云上各点到相交线的距离，得到初步测量结果；最后，基于残差估计对初步测量结果进行误差校正，得到最终的测量结果。使用尺寸标准及表面具有缺陷的两类电缆接头点云进行测量实验，测量结果的绝对误差分别小于0.2 mm与1.0 mm，相对误差分别小于0.5%与1.5%，说明所提算法具有较高的鲁棒性与测量精度。
测量 三维点云处理 交联聚乙烯电缆接头 反应力锥 参数测量 机器视觉
1 东莞理工学院 电子工程与智能化学院，广东 东莞 523808
2 深圳大学 物理与光电工程学院，广东 深圳 518060
3 广东工业大学 物理与光电工程学院，广东 广州 510006
高重复频率的飞秒激光在高速激光测距和三维成像等领域有着非常重要的作用。其中基于飞秒光纤激光器的高次谐波锁模是获得GHz量级以上高重复频率脉冲的重要手段之一。基于含腔内光栅对色散补偿的非线性偏振旋转（NPR）锁模的掺镱（Yb）光纤激光器，在180 mW泵浦光时获得了稳定的143 MHz基频锁模脉冲序列，当泵浦光功率升至1 W时获得了最高20次谐波（2.86 GHz）锁模脉冲序列输出。系统地对比研究了基频锁模与高次谐锁模状态下，脉冲重复频率精密锁定后的艾伦偏差和相位噪声，7次谐波锁模状态下重复频率锁定精度能够保持在10−13 Hz@1 s的稳定度，为高次谐波锁模飞秒激光脉冲序列用于精密测量提供了实验依据。
高次谐波锁模 飞秒掺镱光纤激光器 脉冲重复频率 时间抖动 相位噪声 high-order harmonic mode locking femtosecond Ytterbium-doped fiber laser pulse repetition frequency time jitter phase noise 红外与激光工程
2022, 51(8): 20210779
Author Affiliations
Abstract
1 Department of Electronic Engineering, Xiamen University, Xiamen 361005, China
2 Shenzhen Research Institute of Xiamen University, Shenzhen 518057, China
3 Department of Physics, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China
We report on the direct generation of passively mode-locked vortex lasers in the visible spectral region, for the first time to the best of our knowledge, using a (Pr:YLF) crystal as the gain medium. A stable mode-locked mode has been achieved with a maximum average output power of 75 mW using a graphene saturable absorber mirror. The mode-locked pulse width is measured to be as short as about 73.4 ps at a repetition rate of about 140 MHz, and the laser wavelength is at about 721 nm with spectral width of about 0.5 nm. By slightly misaligning the laser resonator, a first-order Laguerre-Gaussian mode () has also been obtained with output power reduced to about 22 mW. The achieved mode has been verified via a home made improved Fizeau interferometer. This work provides a simple and universal method for direct generation of an ultrafast vortex laser, which can be readily extended to other spectral regions by using different laser gain mediums.
Photonics Research
2019, 7(11): 11001209
Author Affiliations
Abstract
Core mineral spectrometer is one of the advanced and important tools for core digitalization, altered mineral mapping, ore deposits exploring, and ore-searching in surrounding mine and beneficiation process. In this letter, a new core mineral spectrometer (CMS 350) is designed and developed. The basic principle, structural design, function module, key components, data acquisition, and processing methods of CMS 350 are introduced. In addition, some applications and results of CMS 350 in Zijin Mining are presented to validate the performance of CMS 350.
300.6190 Spectrometers 000.3110 Instruments, apparatus, and components common to the sciences Chinese Optics Letters
2014, 12(8): 083002
