固连双相机多视图重建测量方法设计

Multi-view reconstruction measurement design based on binocular camera

大范围场景光学非接触式测量在工程中具有广泛的应用需求,常规基于单相机的多视图重建测量方法需要在场景中加入尺度基准,图像采集过程复杂、对图像重合度要求高。为此提出一种利用固连双目相机进行多视图重建的方法,既继承多视图重建中测量范围大的优势,同时又无须尺度基准,图像采集过程更简单易实现,数据优化过程中还额外增加了双相机固连约束条件。具体实现过程中,首先标定获取安装在固定杆上的两相机的内参数及固连关系,然后使用双相机对待测量区域采集图像并双目交会获取每一时刻的空间点云。计算相邻时刻点云所在坐标系的转换关系,通过传递将所有时刻图像对应相机位姿以及交会点云统一在指定坐标系下,由光束法平差优化相机位姿及点云坐标,由重建点云坐标即可计算待测尺寸参数及形变信息。经实验验证,在5 m范围内,其测量误差最大3 mm,均值1 mm。该方法可以满足大尺寸物体、大范围场景的测量需求且稳定可靠。

Optical non-contact measurement of large-scale scenes has wide application in engineering.The multi-view reconstruction based on a single camera needs to arrange scale datum into the measurement area,and the image acquisition process is complex and requires a high overlap ratio between adjacent images.Therefore,a method of multi-view reconstruction using binocular cameras was presented.This method not only inherits the advantages of large measurement range in multi-view reconstruction,but also does not need to arrange scale datum,and the image acquisition process is simpler.Besides,the double camera constraint was added in the process of data optimization.Specific methods are as follows:firstly the internal parameters and solid connection of two cameras installed on the fixed rod were obtained according to camera calibration;then the binocular cameras were used to acquire the images of the area to be measured and obtain the spatial point cloud by binocular intersection.The transformation relation of the coordinate system of point cloud in adjacent time was calculated by the method of pose estimation,and the camera′s parameters and point cloud′s coordinate of each moment were transformed to the specified coordinate system.The position and pose of the camera and the coordinate of point cloud were optimized by using the bundle adjustment,and the size parameters and the deformation information were calculated from the point cloud coordinates.The test results show that in the range of 5 m,the measurement′s error is 3 mm,the average error is 1 mm.This method is suitable for the measurement of large scale object and scene and is stable and reliable.