煤矿井下视觉同步定位与地图构建SLAM(Simultaneous Localization and Mapping)应用中,光照变化与低纹理场景严重影响特征点的提取和匹配结果,导致位姿估计失败,影响定位精度。提出一种基于改进定向快速旋转二值描述符ORB(Oriented Fast...煤矿井下视觉同步定位与地图构建SLAM(Simultaneous Localization and Mapping)应用中,光照变化与低纹理场景严重影响特征点的提取和匹配结果,导致位姿估计失败,影响定位精度。提出一种基于改进定向快速旋转二值描述符ORB(Oriented Fast and Rotated Brief)-SLAM3算法的煤矿井下移动机器人双目视觉定位算法SL-SLAM。针对光照变化场景,在前端使用光照稳定性的Super-Point特征点提取网络替换原始ORB特征点提取算法,并提出一种特征点网格限定法,有效剔除无效特征点区域,增加位姿估计稳定性。针对低纹理场景,在前端引入稳定的线段检测器LSD(Line Segment Detector)线特征提取算法,并提出一种点线联合算法,按照特征点网格对线特征进行分组,根据特征点的匹配结果进行线特征匹配,降低线特征匹配复杂度,节约位姿估计时间。构建了点特征和线特征的重投影误差模型,在线特征残差模型中添加角度约束,通过点特征和线特征的位姿增量雅可比矩阵建立点线特征重投影误差统一成本函数。局部建图线程使用ORB-SLAM3经典的局部优化方法调整点、线特征和关键帧位姿,并在后端线程中进行回环修正、子图融合和全局捆绑调整BA(Bundle Adjustment)。在EuRoC数据集上的试验结果表明,SL-SLAM的绝对位姿误差APE(Absolute Pose Error)指标优于其他对比算法,并取得了与真值最接近的轨迹预测结果:均方根误差相较于ORB-SLAM3降低了17.3%。在煤矿井下模拟场景中的试验结果表明,SL-SLAM能适应光照变化和低纹理场景,可以满足煤矿井下移动机器人的定位精度和稳定性要求。展开更多
SLAM(simultaneous localization and mapping)是无人载体实现自主导航定位的关键技术。针对传统视觉SLAM系统在动态场景下导航定位精度低的问题,在视觉SLAM系统的基础上引入惯性传感器(inertial measure-ment unit)。在ORB-SLAM3系统...SLAM(simultaneous localization and mapping)是无人载体实现自主导航定位的关键技术。针对传统视觉SLAM系统在动态场景下导航定位精度低的问题,在视觉SLAM系统的基础上引入惯性传感器(inertial measure-ment unit)。在ORB-SLAM3系统的基础上设计了一种面向动态环境的视觉惯性SLAM系统。提出一种基于向量场一致性(vector field consensus,VFC)的稀疏光流法来追踪图像的特征点并计算基础矩阵,分别利用光流对极几何约束和惯性传感器信息计算特征点的动态概率,提出一种联合的动态特征检测方法计算特征点的总动态概率,并将动态概率大于阈值的特征点进行剔除,在SLAM系统的前端实现了视觉信息与惯性运动信息的紧耦合。在数据集上的实验结果表明,该视觉惯性SLAM改进算法有良好的性能表现。展开更多
平面特征作为一种高层几何特征而广泛存在于结构化环境中,对于大多数同时定位与地图构建(Simultaneous Localization and Mapping,SLAM)系统来说是个很好的补充。为了解决特征点与平面特征融合时引入了新的误差并且平面存在着退化的可能...平面特征作为一种高层几何特征而广泛存在于结构化环境中,对于大多数同时定位与地图构建(Simultaneous Localization and Mapping,SLAM)系统来说是个很好的补充。为了解决特征点与平面特征融合时引入了新的误差并且平面存在着退化的可能,本文提出了一个融合异质特征的单目视觉惯性SLAM系统。首先从灰度图像中提取特征点;其次对特征点集合进行三角剖分,并将三角剖分的结果转换到世界坐标系下;接着将初始化过程建模为有约束的优化问题,并用交替方向乘子法分布式求解;然后对相似平面进行聚类,并用所提出的平面碰撞概率模型拟合平面,得到对应的有界平面参数;最后在因子图中引入了平面特征的几何约束,通过误差模型同时优化相机运动以及平面参数。与典型的视觉惯性SLAM系统VINS相比,本文提出的系统在EuRoC数据集的绝对轨迹误差平均值降低了50%;在TUM-Ⅵ数据集的绝对轨迹误差平均值降低了40%。该方法能够在结构化场景中稳定、连续地工作,并且提高了弱纹理区域的定位精度和鲁棒性。展开更多
vSLAM(visual Simultaneous Localization and Mapping)是一种基于视觉传感器实现同时定位与建图的技术,不仅可为地面机器人提供服务,同时在无人机的定位导航中也有着非常重要的应用。对基于无人机的vSLAM发展概况进行整理研究,就其中...vSLAM(visual Simultaneous Localization and Mapping)是一种基于视觉传感器实现同时定位与建图的技术,不仅可为地面机器人提供服务,同时在无人机的定位导航中也有着非常重要的应用。对基于无人机的vSLAM发展概况进行整理研究,就其中几大关键方向的研究现状予以介绍,主要包括结合IMU、结合光流传感器的vSLAM,同时总结目前研究中仍存在的一些问题和不足之处。结合经典理论与最新研究动态,对基于无人机的vSLAM重点研究内容和未来发展方向提出了新的展望。展开更多
An improved method with better selection capability using a single camera was presented in comparison with previous method. To improve performance, two methods were applied to landmark selection in an unfamiliar indoo...An improved method with better selection capability using a single camera was presented in comparison with previous method. To improve performance, two methods were applied to landmark selection in an unfamiliar indoor environment. First, a modified visual attention method was proposed to automatically select a candidate region as a more useful landmark. In visual attention, candidate landmark regions were selected with different characteristics of ambient color and intensity in the image. Then, the more useful landmarks were selected by combining the candidate regions using clustering. As generally implemented, automatic landmark selection by vision-based simultaneous localization and mapping(SLAM) results in many useless landmarks, because the features of images are distinguished from the surrounding environment but detected repeatedly. These useless landmarks create a serious problem for the SLAM system because they complicate data association. To address this, a method was proposed in which the robot initially collected landmarks through automatic detection while traversing the entire area where the robot performed SLAM, and then, the robot selected only those landmarks that exhibited high rarity through clustering, which enhanced the system performance. Experimental results show that this method of automatic landmark selection results in selection of a high-rarity landmark. The average error of the performance of SLAM decreases 52% compared with conventional methods and the accuracy of data associations increases.展开更多
文摘煤矿井下视觉同步定位与地图构建SLAM(Simultaneous Localization and Mapping)应用中,光照变化与低纹理场景严重影响特征点的提取和匹配结果,导致位姿估计失败,影响定位精度。提出一种基于改进定向快速旋转二值描述符ORB(Oriented Fast and Rotated Brief)-SLAM3算法的煤矿井下移动机器人双目视觉定位算法SL-SLAM。针对光照变化场景,在前端使用光照稳定性的Super-Point特征点提取网络替换原始ORB特征点提取算法,并提出一种特征点网格限定法,有效剔除无效特征点区域,增加位姿估计稳定性。针对低纹理场景,在前端引入稳定的线段检测器LSD(Line Segment Detector)线特征提取算法,并提出一种点线联合算法,按照特征点网格对线特征进行分组,根据特征点的匹配结果进行线特征匹配,降低线特征匹配复杂度,节约位姿估计时间。构建了点特征和线特征的重投影误差模型,在线特征残差模型中添加角度约束,通过点特征和线特征的位姿增量雅可比矩阵建立点线特征重投影误差统一成本函数。局部建图线程使用ORB-SLAM3经典的局部优化方法调整点、线特征和关键帧位姿,并在后端线程中进行回环修正、子图融合和全局捆绑调整BA(Bundle Adjustment)。在EuRoC数据集上的试验结果表明,SL-SLAM的绝对位姿误差APE(Absolute Pose Error)指标优于其他对比算法,并取得了与真值最接近的轨迹预测结果:均方根误差相较于ORB-SLAM3降低了17.3%。在煤矿井下模拟场景中的试验结果表明,SL-SLAM能适应光照变化和低纹理场景,可以满足煤矿井下移动机器人的定位精度和稳定性要求。
文摘SLAM(simultaneous localization and mapping)是无人载体实现自主导航定位的关键技术。针对传统视觉SLAM系统在动态场景下导航定位精度低的问题,在视觉SLAM系统的基础上引入惯性传感器(inertial measure-ment unit)。在ORB-SLAM3系统的基础上设计了一种面向动态环境的视觉惯性SLAM系统。提出一种基于向量场一致性(vector field consensus,VFC)的稀疏光流法来追踪图像的特征点并计算基础矩阵,分别利用光流对极几何约束和惯性传感器信息计算特征点的动态概率,提出一种联合的动态特征检测方法计算特征点的总动态概率,并将动态概率大于阈值的特征点进行剔除,在SLAM系统的前端实现了视觉信息与惯性运动信息的紧耦合。在数据集上的实验结果表明,该视觉惯性SLAM改进算法有良好的性能表现。
文摘平面特征作为一种高层几何特征而广泛存在于结构化环境中,对于大多数同时定位与地图构建(Simultaneous Localization and Mapping,SLAM)系统来说是个很好的补充。为了解决特征点与平面特征融合时引入了新的误差并且平面存在着退化的可能,本文提出了一个融合异质特征的单目视觉惯性SLAM系统。首先从灰度图像中提取特征点;其次对特征点集合进行三角剖分,并将三角剖分的结果转换到世界坐标系下;接着将初始化过程建模为有约束的优化问题,并用交替方向乘子法分布式求解;然后对相似平面进行聚类,并用所提出的平面碰撞概率模型拟合平面,得到对应的有界平面参数;最后在因子图中引入了平面特征的几何约束,通过误差模型同时优化相机运动以及平面参数。与典型的视觉惯性SLAM系统VINS相比,本文提出的系统在EuRoC数据集的绝对轨迹误差平均值降低了50%;在TUM-Ⅵ数据集的绝对轨迹误差平均值降低了40%。该方法能够在结构化场景中稳定、连续地工作,并且提高了弱纹理区域的定位精度和鲁棒性。
文摘vSLAM(visual Simultaneous Localization and Mapping)是一种基于视觉传感器实现同时定位与建图的技术,不仅可为地面机器人提供服务,同时在无人机的定位导航中也有着非常重要的应用。对基于无人机的vSLAM发展概况进行整理研究,就其中几大关键方向的研究现状予以介绍,主要包括结合IMU、结合光流传感器的vSLAM,同时总结目前研究中仍存在的一些问题和不足之处。结合经典理论与最新研究动态,对基于无人机的vSLAM重点研究内容和未来发展方向提出了新的展望。
文摘An improved method with better selection capability using a single camera was presented in comparison with previous method. To improve performance, two methods were applied to landmark selection in an unfamiliar indoor environment. First, a modified visual attention method was proposed to automatically select a candidate region as a more useful landmark. In visual attention, candidate landmark regions were selected with different characteristics of ambient color and intensity in the image. Then, the more useful landmarks were selected by combining the candidate regions using clustering. As generally implemented, automatic landmark selection by vision-based simultaneous localization and mapping(SLAM) results in many useless landmarks, because the features of images are distinguished from the surrounding environment but detected repeatedly. These useless landmarks create a serious problem for the SLAM system because they complicate data association. To address this, a method was proposed in which the robot initially collected landmarks through automatic detection while traversing the entire area where the robot performed SLAM, and then, the robot selected only those landmarks that exhibited high rarity through clustering, which enhanced the system performance. Experimental results show that this method of automatic landmark selection results in selection of a high-rarity landmark. The average error of the performance of SLAM decreases 52% compared with conventional methods and the accuracy of data associations increases.
