频闪激光光栅条纹光场分布特性和调制控制方法研究

Because of the particularity of the surface size and optical properties, high precision measurement of the device with small size or having complex surface reflection characteristics is a difficult problem in the field of precision measurement. The 3D measurement system based on fringe projection used to measure this kind of devices has been limited by the accuracy of conventional projection equipment. To improve the measuring precision and adaptability of 3D measurement method of fringe projection in this field, this project will start from the light source of fringe projection system, and research in-depth a new light source，the Stroboscopic Laser Fringe-pattern. Stroboscopic Laser Fringe-pattern is produced by a rotating scanning polygon mirror, which convert the precision time modulation line laser signal to precision fine grating fringe with high density, high brightness and fast refresh rate. Stroboscopic Laser Fringe-pattern make full use of high brightness, high precision and the modulation characteristics of laser. To fully explore and use the advantages of Stroboscopic Laser Fringe-pattern in 3D precision measurement, make the fringe more fine in small size measurement and improve the accuracy of the fringe information in measurement of the device with complex reflection surface. This project will have further research of the optical field distribution characteristics of Stroboscopic Laser Fringe-pattern and the corresponding controlling or modulation method. The fringe pattern with high precision fine fringe and high modulation degree will be obtained, which provide good protection for the subsequent fringe analysis and 3D precision measurement.

由于表面尺寸和光学特性的特殊性，微小尺寸或具有复杂表面反射特性器件的高精度测量是精密测量领域的难题，传统基于条纹投影的三维测量系统直接用来测量会受投影设备精度的限制。为提高条纹投影三维测量方法在该领域的测量精度及适应性，本课题从条纹光源投射系统出发，深入研究一种新的条纹投射方法——频闪激光光栅条纹。频闪激光光栅条纹是通过多面镜旋转扫描的方式将时间精密调制的线激光信号转换为精细且密度高，亮度高，刷新频率快的精密光栅条纹。频闪激光光栅条纹充分利用了激光高亮度、高精细度、可调制的特性。为充分挖掘和发挥频闪激光光栅条纹在三维精密测量中的应用优势，提高在微小尺寸测量时条纹光源的细密性和在复杂反射表面器件测量时条纹信息的准确性，本课题深入研究频闪激光光栅条纹的光场分布特性和调制控制方法，获取高精细度、高调制度的条纹图，为后续条纹分析和三维精密测量提供良好保障。

由于表面尺寸和光学特性的特殊性，微小尺寸或具有复杂表面反射特性器件的高精度测量是精密测量领域的难题。为提高条纹投影三维测量方法在该领域的测量精度及适应性，本课题从条纹光源投射系统出发，深入研究一种新的条纹投射方法——频闪激光光栅条纹。频闪激光光栅条纹是通过多面镜旋转或MEMS微振镜扫描的方式将时间精密调制的线激光信号转换为精细且密度高，亮度高，刷新频率快的精密光栅条纹。本课题研究了频闪激光光栅条纹光场分布特性，调制控制方法和高调制度的激光光栅条纹自适应改善方法。.本课题分别完成了基于多面镜旋转和MEMS微振镜的频闪激光光栅条纹光源的搭建，投影条纹的空间分辨率可达0.47mm，相移分辨率为0.12mm，实现了高精细度和高分辨率的激光光栅的投射。利用设计的光源投射到微小尺寸复杂光学反射特性表面器件上进行三维测量。测量结果表明，设计的光源可以很好地测量和显示被测器件的微小高度变化。测量高度为1mm的标准量块，其均方根误差为0.037mm。.为解决条纹投影在复杂反射表面信息缺失的问题，本课题提出了一种基于深度学习的高动态范围条纹自适应改善方法。首先利用低调制区域检测网络获取条纹图中的饱和区域和暗区域，然后利用增强网络来学习条纹整体分布和细节强度来恢复低调制度区域的条纹细节。通过对量块、发动机叶片、焊缝等金属反光表面进行三维测量实验，实验结果表明，所设计的网络能恢复高光表面的低调制区域。对5mm的金属量块测量，其高度均方根误差从0.55mm降低到0.06mm。.本课题的研究成果表明，频闪激光光栅条纹的投射方式能够实现高精细度和高分辨率的激光光栅的投射。提出的基于深度学习的高动态范围条纹自适应改善方法可以有效地提高复杂反射面上投影条纹的质量。解决了条纹投影三维测量方法在复杂反射表面信息缺失的问题。因此本课题的研究成果应用于微小器件或具有复杂反射率表面器件精密的三维测量具有良好的前景。

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