基于姿态阈值滤波的单目视觉农业机械定位方法

Monocular vision agricultural machine localization based on pose threshold filter

精确定位是农业机械实现自动导航的重要前提,提出了一种基于单目摄像机的导航定位算法。算法通过对捕获的每帧图像进行特征点检测与跟踪,基于3D-2D特征点配对方法,还原了车辆行驶过程中的姿态信息。同时,假设车辆前方小区域近似平坦,摄像机离地高度近似固定不变,算法实时求解车辆位移的绝对尺度因子,配合姿态阈值滤波器,对所求姿态信息进行在线修正。实验选择在三种不同的场景进行,以RTK-GPS定位数据作为对比,三种场景的平均相对位置偏差分别为5.459 9%、8.373 1%、6.443 94%,三种不同场景的航向角变化平均值分别为7.717 7°、5.738 9°、3.438 3°。结果表明算法可实现农业机械的自动定位,在短距离范围内具有一定的可靠性。

Precise localization is an important premise of autonomous navigation for agricultural vehicles.We propose a localization algorithm based on monocular camera.After features are detected and tracked through multiple frames,vehicle poses are estimated based on 3 D-2 Dcorrespondences.Furthermore,the translation absolute scale is calculated based on the assumption that the ground patches are locally flat and the camera is moving at a known and fixed height over the ground.Finally,the poses are refined by the pose threshold filter.Compared with the RTK-GPS data,the average relative position errors of the three different experimental terrains are 5.459 9%,8.373 1%and 6.443 94%,and the average heading errors are 7.717 7°,5.738 9°and 3.438 3°.The results show that the algorithm is feasible for agricultural vehicles localization.