基于双棱镜单摄像机立体视觉的P-GMAW熔池表面重建

利用传统的双目立体视觉技术进行焊接熔池表面形貌的三维传感,系统成本昂贵,且拍摄时必须保证同步,摄像机参数的不一致也容易造成重建误差。分析了双棱镜立体视觉系统原理,搭建了一套基于双棱镜的单摄像机立体视觉系统,在一个CCD像面上拍摄到同一物体存在视差的两幅图像,预处理后通过SSD算法求取像素级视差图,然后由二次曲线拟合进一步获得亚像素级视差图,由标定结果求得每个图像点对应的三维坐标。通过搭建的传感系统获得了P-GMAW平板堆焊基值期间的熔池图像,依照上述流程重建了熔池的三维表面形貌,同时针对重建结果做了误差分析,证实了其可靠性。

Surface reconstruction of P-GMAW weld pool based on single camera biprism-stereo system

The 3Dsensing of weld pool surface morphology is expensive and difficult to make two cameras take photos simultaneously by the traditional technology of binocular stereo vision.Reconstruction error is also resulted from the different parameters of two cameras.The principle of biprism-stereo system is analyzed.A stereo vision sensing system based on biprism-single camera is designed to take two images of one object on the same CCD image plane.There exits disparity between two images： pixel-level disparity map is calculated by SSD matching algorithm from two images after pretreatment,sub-pixel level disparity map is resulted from pixel-level disparity map by quadratic curve fitting.Three-dimensional coordinate of every pixel is calculated by the result of calibration.The pool images during the base period of P-GMAW are obtained by sensing system,weld pool surface morphology according to above process is reconstructed.The surface reconstruction error of weld pool is analyzed to verify its reliability.