挡风玻璃三维形貌测量系统的设计

Design of Measuring System of the Three-dimension Topography of the Windshield

以双目立体视觉理论为基础,设计了一种汽车挡风玻璃三维形貌测量系统。标定好双目系统后,投影黑色背景下有序排列的两列白色方格。使用斑点提取算法提取方格中心点相面坐标,经过排序和匹配,将点对代入双目模型,求出方格中心点在相机坐标系下的三维坐标。提取视场内标记点的中心在相机坐标系下的坐标,建立玻璃坐标系,求取玻璃坐标系和相机坐标系间的转换关系,然后将投影方格获得的相机坐标系下坐标转化为玻璃坐标系下坐标。通过多次投影、移动测量系统和坐标转换,逐渐实现挡风玻璃表面的扫描测量。实验结果表明,双目标定重投影误差为1.36μm;挡风玻璃整体测量误差在±1mm之内。

The three-dimensional shape of the whole windscreen is proposed which is based on the theory of binocular stereo vision. After the binocular system is well calibrated, two columns of the white squares which are arranged in a black background in order is projected. An algorithm to extract the spots is used to extract the physiognomy coordinates of the center points of the squares. The three-dimensional coordinates of the center points of the squares at the camera coordinate system are got after the physiognomy coordinates of the center points of the squares are sorted, matched and substituted into the binocular model. The three-dimensional coordinates of the center of the marked points at the camera coordinate system are got to establish the glass coordinate system and to obtain the conversion relations between the glass coordinate system and the camera coordinate system. After the relationship between the two coordinates are got, the coordinates of the projection grids in the coordinates of the glass system are obtained. The scanning measurement of the windshield surface is gradually achieved by projecting many times, moving the measurement system and coordinate transformation. Experiments show that the error of reprojection of binocular calibration is 1.36 μm and the overall measurement error of the windshield is within ±1 mm.