针对轨道扣件表面结构复杂导致的线结构光照射分布不均匀问题，研究了一种基于改进灰度重心法的光条中心线提取方法，精准重构了轨道扣件点云模型。基于点云模型提取了轨道扣件的结构特征信息，建立了轨道扣件缺陷检测组合分类器模型，实现了轨道扣件的弹条缺失、扣件歪斜、螺母缺失等缺陷检测。研究了基于表面法向量的螺母上平面解析方法，通过螺母松动测量实验实现了轨道扣件的松动检测。搭建了扣件故障诊断实验平台并开展了相关实验研究，实验结果表明，系统扣件故障检出率达到96%，扣件松紧度测量的总体误差低于0.2 mm，扣件故障诊断系统的检测效果和鲁棒性较好，对列车安全运行具有重要的现实意义。
测量 三维图像处理 轨道扣件 线结构光 中心线提取 故障诊断
1 中国科学院大连化学物理研究所化学激光重点实验室, 辽宁 大连 116023
2 长春理工大学理学院, 吉林 长春 130022
3 中国科学院大学, 北京 100049
532 nm激光泵浦H2,CH4和CO2三种拉曼活性气体混合物时产生的拉曼激光覆盖较宽的可见光波段,可以作为多光谱激光的照明光。分别讨论了单种气体中的受激拉曼散射和四波混频过程,比较了各阶拉曼分量随压力和泵浦能量的变化。发现在低压条件下,当高能量激光泵浦时,每种气体的各阶斯托克斯分量(尤其是一阶斯托克斯光)的转换效率基本保持稳定。在混合拉曼活性气体的实验中,通过控制不同气体之间的压力比,实现了13条光谱线的同时输出,其中574,630,683,771 nm激光在200 mJ以上的高能量区域具有非常接近的转换效率(6.5%~8%)。
激光光学 多光谱激光 受激拉曼散射 混合气体 四波混频 中国激光
2021, 48(21): 2101006
Author Affiliations
Abstract
1 Key Laboratory of Chemical Lasers, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 School of Science, Changchun University of Science and Technology, Changchun 130022, China
In this work, SF6 as a Raman-active medium is investigated to generate a multispectral Raman laser by the combination of cascade stimulated Raman scattering (SRS) and four wave mixing. The Raman frequency comb from the 10th-order anti-Stokes to the 9th-order Stokes was generated, and its spectral range covered 377–846 nm. The photon conversion efficiency of 16.4% for the first Stokes was achieved, and the Raman gain coefficient at 1.5 MPa of SF6 under the 532 nm pump laser was calculated to be 0.83 cm/GW by the SRS threshold comparison with H2. Using helium as the carrier gas, the thermal effect of the SF6 Raman laser was improved dramatically under a repetition rate of 10 Hz.
multispectral Raman laser Raman frequency comb stimulated Raman scattering four wave mixing conversion efficiency Chinese Optics Letters
2020, 18(5): 051402
