Xu Guan, Chen Fang, Wu Guangwei, Li Xiaotao
Transportation College, Nanling Campus, Jilin University, Renmin Str. 5988#, Changchun, China.
School of Mechanical Science and Engineering, Nanling Campus, Jilin University, Renmin Str. 5988#, Changchun, China.
Sci Rep. 2018 May 8;8(1):7198. doi: 10.1038/s41598-018-25572-9.
An active solution method of the homography, which is derived from four laser lines, is proposed to recover the pavement cracks captured by the camera to the real-dimension cracks in the pavement plane. The measurement system, including a camera and four laser projectors, captures the projection laser points on the 2D reference in different positions. The projection laser points are reconstructed in the camera coordinate system. Then, the laser lines are initialized and optimized by the projection laser points. Moreover, the plane-indicated Plücker matrices of the optimized laser lines are employed to model the laser projection points of the laser lines on the pavement. The image-pavement homography is actively determined by the solutions of the perpendicular feet of the projection laser points. The pavement cracks are recovered by the active solution of homography in the experiments. The recovery accuracy of the active solution method is verified by the 2D dimension-known reference. The test case with the measurement distance of 700 mm and the relative angle of 8° achieves the smallest recovery error of 0.78 mm in the experimental investigations, which indicates the application potentials in the vision-based pavement inspection.
提出了一种基于四条激光线的单应性主动求解方法，用于将相机捕捉到的路面裂缝恢复为路面平面中实际尺寸的裂缝。测量系统包括一台相机和四个激光投影仪，可在不同位置捕捉二维参考面上的投影激光点。投影激光点在相机坐标系中进行重建。然后，利用投影激光点对激光线进行初始化和优化。此外，采用优化后激光线的平面指示普吕克矩阵对激光线在路面上的投影激光点进行建模。通过投影激光点垂足的解主动确定图像-路面单应性。在实验中，通过单应性的主动求解来恢复路面裂缝。通过二维尺寸已知的参考物验证了主动求解方法的恢复精度。在实验研究中，测量距离为700 mm、相对角度为8°的测试案例实现了最小恢复误差0.78 mm，这表明了该方法在基于视觉的路面检测中的应用潜力。
