顾及系统误差的三维激光扫描坐标转换

地面激光扫描仪设备坐标系是正交的三维直角坐标系,工程测量坐标系是用高斯平面坐标和高程来表达和研究三维实体的,不是严格正交的,用刚性三维坐标变换模型解算坐标转换参数,存在模型误差。因而本文提出了刚性化模型,顾及了归算和投影变形,以及大气折光和地球曲率等系统误差的综合影响,并在扫描区距离不同中央子午线的情况下,验证了刚性化模型可以有效消除系统误差的影响,从而保证了点云坐标转换后的精度及稳定性。

Flexible Calibration Method for 3D Laser Scanner System

In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the unified reference coordinate system. A flexible planar calibration pattern was introduced to the calibration process, which can be arbitrarily placed and from which the known feature points can be extracted to construct other unknown feature points. With the known intrinsic parameters, the laser projector plane equation was fitted by the multi-noncollinear points, which were acquired through the principle of triangulation and the projective invariance of cross ratio. With this method, the strict alignment and multiple times of coordinate transformation can be avoided. Experimental results showed that the arithmetic mean of the root mean square(RMS) error of distance was 0.000 7 mm.

单站点云坐标转换参数的线性拟合解算方法

针对三维坐标转换公式是非线性的,会造成在旋转角度任意大小时影响平差计算转换参数的问题,该文根据罗德里格矩阵的性质,建立坐标转换的线性拟合模型,计算6个拟合参数,并计算坐标转换参数。利用三维激光扫描仪获得物体形状信息后,需要将点云坐标系统转换成工程测量中使用的国家或地方坐标(指定坐标)系。多站实验后的数据分析表明,平面点位误差为21.27mm,高程中误差为18.96mm,证明此方法可靠有效。

曲面基底衍射光学元件的激光直写技术

飞秒激光直写技术(FsLDW)因其优异的三维加工能力、高空间分辨率、低附加损伤等优点被广泛地应用于微纳加工领域,但传统飞秒激光直写技术在加工效率、加工面积和加工精度之间存在矛盾。为了实现高速、大面积、高精度的激光微纳加工,构建了一种由大范围水平位移台和高速旋转台组成的极坐标系飞秒激光直写系统。基于该系统,研究了轴对称样品中心对准方法及曲面曲率校准方法,并在曲面上制备了多阶三维结构。最终完成了在透镜曲面上制备直径为10mm的衍射圆光栅结构,实现了飞秒激光高速、大尺寸、高精度地制备大面积三维结构。该研究为高性能折衍混合光学元件的制备提供了有力的技术支持。