基于双目立体视觉的重叠柑橘空间定位     

刘妤  刘洒  杨长辉  王恺  谢铌 《中国农业科技导报》2020,22(9):104-112

果实的精准识别和定位是智能采摘面临的难题之一。基于双目立体视觉,提出了一种针对户外重叠柑橘的三维空间定位方法。首先,从双目左右图像中提取重叠柑橘果实轮廓并进行高斯平滑,通过曲率分析,找出异常的轮廓像素点;其次,依次连接相邻两个异常像素点,分析该线段上的像素点到柑橘轮廓的距离,在相邻两正常线段的交点处完成重叠柑橘轮廓分割,并通过寻找异常线段剔除对应的非柑橘轮廓像素点;再者,采用最小二乘椭圆拟合方法重建柑橘目标轮廓,并获取柑橘的中心;最后,根据双目极线约束和图像相似度,对重叠柑橘中心点进行匹配,并基于视差原理计算柑橘中心的深度值及三维空间坐标,确定重叠柑橘的遮挡关系。户外实验结果表明,所提出的方法定位误差为6.38 mm,满足柑橘采摘机器人户外采摘作业的定位精度要求。  相似文献   

双目立体视觉在果树采摘机器人中的应用   总被引：1，自引：0，他引：1  

赵鹏  赵德安 《农机化研究》2009,31(1)

果树采摘机器人是未来智能农业机械化的发展方向,具有广阔的应用前景。为此,针对果树采摘机器人作业环境的复杂性与定位目标的特殊性,从双目定位的几何模型出发,归纳了双目定位的基本过程,总结了立体视觉的摄像机标定问题,提出变焦距双目视觉定位果实的研究方向,并对双目图像的匹配问题进行了分析。  相似文献   

无人机机载激光雷达提取果树单木树冠信息   总被引：2，自引：3，他引：2  

陈日强  李长春  杨贵军  杨浩  徐波  杨小冬  朱耀辉  雷蕾  张成健  董震 《农业工程学报》2020,36(22):50-59

定株管理是未来果园精准生产管理的趋势,果树单木树冠信息的提取是定株管理的关键。该研究利用无人机采集的苹果园激光探测与测量数据（Light Detection and Ranging,LiDAR）检测和测量每棵果树的树冠面积和树冠直径,并评价空间分辨率对于果树单木树冠检测与提取的影响。该方法主要包括使用反距离权重插值法间接生成冠层高度模型（Canopy Height Model,CHM）;使用局部极大值滤波算法和标记控制分水岭分割算法（Marked-Controlled Watered Segmentation,MCWS）对果树进行单木树冠检测与提取,通过与参考数据的比较,评估了该方法的精度,并定量分析了空间分辨率对于单木树冠检测与信息提取结果的敏感性。结果表明,该方法有效地实现果树单木树冠检测与信息提取,代表果树检测精度的F1得分为94.86%,树冠轮廓提取准确率为86.39%,树冠面积的提取数据集和参考数据集的线性拟合结果决定系数和归一化均方根误差分别为0.81和20.56%,树冠直径的提取数据集和参考数据集的线性拟合结果决定系数和归一化均方根误差分别为0.85和14.79%,树冠面积和直径不同程度地被高估。此外,冠层高度模型的空间分辨率接近果树平均树冠直径的1/10时精度最高,可以有效检测果树单木树冠及提取树冠轮廓,从而准确提取果树单木树冠信息。  相似文献   

基于激光雷达的巡检机器人导航系统研究   总被引：1，自引：0，他引：1  

季宇寒  李寒  张漫  王琪  贾稼  王库 《农业机械学报》2018,49(2):14-21

智能巡检机器人能够高效、可靠地完成巡检任务,降低工作人员的劳动强度,准确、稳定的导航定位是巡检机器人执行巡检任务的基础。本文研究了基于激光雷达的巡检机器人导航系统,可实现机器人在室内外环境下的地图建立、路径规划和导航定位。导航系统由远程监控平台与巡检机器人组成,远程监控平台发布巡检任务、监控机器人状态、查询与存储检测数据,巡检机器人可实现自主导航定位、遍历检测点、执行数据采集等巡检任务,二者通过无线网络实现远程数据交互。融合激光雷达与编码器信息,使用高鲁棒性Gmapping算法建立二维环境地图。根据地图与检测点信息,采用分支界定算法搜索最优巡检路线,以减少巡检时间和能源消耗。使用自适应蒙特卡罗定位(AMCL)算法估计机器人位置和姿态,结合巡检路线,进行导航定位。根据横向偏差与航向偏差,通过经典的PID算法完成机器人驱动控制。机器人搭载可见光相机与红外相机,可对目标进行可见光通道与红外通道的融合图像检测。对巡检机器人进行了室内导航定位试验,试验结果表明,在1 m/s的速度下,位置与航向偏差的平均绝对误差(MAE)分别小于5 cm和1.1°,标准差(SD)分别小于5 cm和1.5°,能够满足巡检导航定位的要求。  相似文献   

基于无线测距的农业机器人导航定位方法     

侯忠坤 《农机化研究》2012,(4):72-74,78

针对农业机器人应用中的自主导航问题,提出了一种基于无线测距的导航定位方法。首先,分析了机器人的机械模型和位姿描述;然后,阐述了超宽带测距的原理,并分析了基于超宽带测距的定位模型;最后,设计了基于卡尔曼滤波器的多信标传感器信息融合算法。该方法稳定性高,操作简便,解决了农业机器人在恶劣和未知作业环境中的导航定位问题。  相似文献   

Characterization of mobile LiDAR data collected with multiple echoes per pulse from crowns during foliation     

《Scandinavian Journal of Forest Research》2012,27(3):298-311

Abstract

As a state-of-the-art technology for fine-scale forest investigation, mobile terrestrial light detection and ranging (LiDAR), also referred to as mobile laser scanning (MLS), recently has been increasingly exploited to improve its performance on this task. One potential solution is to apply special MLS systems with the capability of collecting multiple echoes per pulse (multi-echoes, for short) from canopies. The methodologies of this rationale turned out to perform better but still insufficiently for canopy properties retrieval, owing to their common defective premise. That is, the knowledge of the characteristics of MLS scan data comprising multi-echoes, so far, is in shortage, especially when regarding the dynamic process of tree foliation. As a pioneering work for this challenge, this study attempted to comprehensively analyze the characteristics of MLS multi-echoes collected from tree crowns during foliation. Specifically, new stable multi-echoes-related features were deduced under the schematic frame of relative quantification, in both spatial and temporal sense. “Relative” here briefly means the division operation deployed on the attributes of multi-echoes, individually in terms of the number of echoes, echo width and crown volume integrity, between their different return orders. Then, the “relative” schematic was primarily validated for more stably representing crown properties during foliation, based on the real data that was collected by the Sensei MLS system with a maximum of three echoes per pulse. Further, a case of tree species classification was examined using a linear discriminant classifier, and it was testified that the resultant temporal statistical rules of multi-echoes as the reverse clues can enhance the performance of MLS in applications.  相似文献   

Human Exposure to Rabid Free‐Ranging Cats: A Continuing Public Health Concern in Pennsylvania     

E. R. Campagnolo  L. R. Lind  J. M. Long  M. E. Moll  J. T. Rankin  K. F. Martin  M. P. Deasy  V. M. Dato  S. M. Ostroff 《Zoonoses and public health》2014,61(5):346-355

Rabid free‐ranging cats have been a public health concern in Pennsylvania since raccoon variant rabies first was recognized in the state in the early 1980s. Over the last decade, between 1.5 and 2.5% of cats submitted to Pennsylvania's state laboratories for rabies testing have been positive. In this report, we describe the extent of rabies in free‐ranging cats in Pennsylvania. We also present two examples of human exposure to rabid free‐ranging cats that occurred in Pennsylvania during 2010–2011 and the public health actions taken to address rabies exposure in the humans and animals. We then describe the concerns surrounding the unvaccinated and free‐ranging cat population in Pennsylvania and possible options in managing this public and animal health problem.  相似文献   

基于超声波技术的棉花打顶装置设计     

马强  ;史增录  ;张学军  ;丁永前  ;鄢金山  ;孙杰  ;丁亚鹏 《农业机械化与电气化》2014,(8):28-29

棉花打顶机械是棉花高效生产急需配套解决的主要技术装备之一。应用三维参数化设计软件Solidworks设计一种基于超声波技术的棉花打顶装置,介绍该装置的总体结构和工作原理,阐述该装置的总体及关键部件的设计方案。使用该装置可实现棉花精确打顶。  相似文献   

Homogeneous habitat can meet the discrete and varied resource requirements of hares but may set an ecological trap     

Neil Reid  Robbie A. McDonald 《Biological conservation》2010,143(7):1701-1706

In common with other farmland species, hares (Lepus spp.) are in widespread decline in agricultural landscapes due to agricultural intensification and habitat loss. We examined the importance of habitat heterogeneity to the Irish hare (Lepus timidus hibernicus) in a pastoral landscape. We used radio-tracking during nocturnal active and diurnal inactive periods throughout one year. In autumn, winter and spring, hares occupied a heterogeneous combination of improved grassland, providing food, and Juncus-dominated rough pasture, providing refuge. In summer, hares significantly increased their use of improved grassland. This homogeneous habitat can fulfil the discrete and varied resource requirements of hares for feeding and shelter at certain times of year. However, improved grassland may be a risky habitat for hares as silage harvesting occurs during their peak birthing period of late spring and early summer. We therefore posit the existence of a putative ecological trap inherent to a homogeneous habitat of perceived high value that satisfies the hares’ habitat requirements but which presents risks at a critical time of year. To test this hypothesis in relation to hare populations, work is required to provide data on differential leveret mortality between habitat types.  相似文献   

Influence of tree crown characteristics on the local PM10 distribution inside an urban street canyon in Antwerp (Belgium): A model and experimental approach     

《Urban Forestry & Urban Greening》2016

Apart from influencing the amount of leaf-deposited particles, tree crown morphology will influence the local distribution of atmospheric particles. Nevertheless, tree crowns are often represented very rudimentary in three-dimensional air quality models. Therefore, the influence of tree crown representation on the local ambient PM₁₀ concentration and resulting leaf-deposited PM₁₀ mass was evaluated, using the three-dimensional computational fluid dynamics (CFD) model ENVI-met^® and ground-based LiDAR imaging. The modelled leaf-deposited PM₁₀ mass was compared to gravimetric results within three different particle size fractions (0.2–3, 3–10 and >10 μm), obtained at 20 locations within the tree crown. Modelling of the LiDAR-derived tree crown resulted in altered atmospheric PM₁₀ concentrations in the vicinity of the tree crown. Although this model study was limited to a single tree and model configuration, our results demonstrate that improving tree crown characteristics (shape, dimensions and LAD) affects the resulting local PM₁₀ distribution in ENVI-met. An accurate tree crown representation seems, therefore, of great importance when aiming at modelling the local PM distribution.  相似文献