In this paper a semi-direct visual odometry and mapping system is proposed with a RGB-D camera,which combines the merits of both feature based and direct based methods.The presented system directly estimates the camer...In this paper a semi-direct visual odometry and mapping system is proposed with a RGB-D camera,which combines the merits of both feature based and direct based methods.The presented system directly estimates the camera motion of two consecutive RGB-D frames by minimizing the photometric error.To permit outliers and noise,a robust sensor model built upon the t-distribution and an error function mixing depth and photometric errors are used to enhance the accuracy and robustness.Local graph optimization based on key frames is used to reduce the accumulative error and refine the local map.The loop closure detection method,which combines the appearance similarity method and spatial location constraints method,increases the speed of detection.Experimental results demonstrate that the proposed approach achieves higher accuracy on the motion estimation and environment reconstruction compared to the other state-of-the-art methods. Moreover,the proposed approach works in real-time on a laptop without a GPU,which makes it attractive for robots equipped with limited computational resources.展开更多
传统视觉即时定位与建图(SLAM)算法若无回环检测可能会存在累积误差无法消除的现象,即使有回环检测,也因准确率和效率比较低而无法应用于轻量级设备上,为此,研究一种回环检测优化的视觉SLAM算法.前端估计时,对相邻帧图像进行ORB(oriente...传统视觉即时定位与建图(SLAM)算法若无回环检测可能会存在累积误差无法消除的现象,即使有回环检测,也因准确率和效率比较低而无法应用于轻量级设备上,为此,研究一种回环检测优化的视觉SLAM算法.前端估计时,对相邻帧图像进行ORB(oriented fast and rotated brief)特征提取与匹配,对匹配成功的特征点进行PnP(perspective-n-point)求解,获得相机运动估计并筛选出关键帧图像;后端优化时,利用SqueezeNet卷积神经网络(CNN)提取图像的特征向量,计算余弦相似度判断是否出现回环,若出现回环则在位姿图中增加相应约束,利用图优化理论对全局位姿进行整体优化;最后利用项目组制作的数据集和TUM(technical university of munich)公开数据集进行测试与对比.研究结果表明:相比于无回环检测算法,本文方法可以成功检测到回环并为全局轨迹优化增添约束;相比于传统词袋法,在回环检测准确率相同的情况下,本文方法召回率可提高21%且计算耗时减少74%;与RGB-D(red green blue-depth)SLAM算法相比,本文方法建图误差可降低29%.展开更多
从同时定位与地图构建(Simultaneous Localization And Mapping,SLAM)的研究进程出发,通过回顾SLAM近三十年来的研究方法,对移动机器人SLAM的研究进行系统的总结,并指出其存在的三个关键问题.针对这三个问题,介绍了基于概率估计和基于...从同时定位与地图构建(Simultaneous Localization And Mapping,SLAM)的研究进程出发,通过回顾SLAM近三十年来的研究方法,对移动机器人SLAM的研究进行系统的总结,并指出其存在的三个关键问题.针对这三个问题,介绍了基于概率估计和基于视觉的SLAM方法,对基于概率估计的SLAM实现方法进行对比总结,并对视觉传感器的不同特性对基于视觉的SLAM方法研究进展进行阐述,随后对比分析不同方法的优缺点,讨论了视觉SLAM存在的问题.最后展望SLAM未来的发展方向.展开更多
视觉SLAM(Simultaneous Localization And Mapping,同时定位与建图)是移动机器人领域的核心技术,传统视觉SLAM还难以适用于高动态场景并且地图中缺少语义信息。提出一种动态环境语义SLAM方法,用深度学习网络对图像进行目标检测,检测动...视觉SLAM(Simultaneous Localization And Mapping,同时定位与建图)是移动机器人领域的核心技术,传统视觉SLAM还难以适用于高动态场景并且地图中缺少语义信息。提出一种动态环境语义SLAM方法,用深度学习网络对图像进行目标检测,检测动态目标所在区域,对图像进行特征提取并剔除动态物体所在区域的特征点,利用静态的特征点进行位姿计算,对关键帧进行语义分割,在构建语义地图时滤除动态物体的地图点构建出无动态物体干扰的语义地图。在TUM数据集上进行实验,结果显示该方法在动态环境下可以提升88.3%位姿估计精度,并且可同时构建出无动态物体干扰的语义地图。展开更多
基金Supported by the National Natural Science Foundation of China(61501034)
文摘In this paper a semi-direct visual odometry and mapping system is proposed with a RGB-D camera,which combines the merits of both feature based and direct based methods.The presented system directly estimates the camera motion of two consecutive RGB-D frames by minimizing the photometric error.To permit outliers and noise,a robust sensor model built upon the t-distribution and an error function mixing depth and photometric errors are used to enhance the accuracy and robustness.Local graph optimization based on key frames is used to reduce the accumulative error and refine the local map.The loop closure detection method,which combines the appearance similarity method and spatial location constraints method,increases the speed of detection.Experimental results demonstrate that the proposed approach achieves higher accuracy on the motion estimation and environment reconstruction compared to the other state-of-the-art methods. Moreover,the proposed approach works in real-time on a laptop without a GPU,which makes it attractive for robots equipped with limited computational resources.
文摘传统视觉即时定位与建图(SLAM)算法若无回环检测可能会存在累积误差无法消除的现象,即使有回环检测,也因准确率和效率比较低而无法应用于轻量级设备上,为此,研究一种回环检测优化的视觉SLAM算法.前端估计时,对相邻帧图像进行ORB(oriented fast and rotated brief)特征提取与匹配,对匹配成功的特征点进行PnP(perspective-n-point)求解,获得相机运动估计并筛选出关键帧图像;后端优化时,利用SqueezeNet卷积神经网络(CNN)提取图像的特征向量,计算余弦相似度判断是否出现回环,若出现回环则在位姿图中增加相应约束,利用图优化理论对全局位姿进行整体优化;最后利用项目组制作的数据集和TUM(technical university of munich)公开数据集进行测试与对比.研究结果表明:相比于无回环检测算法,本文方法可以成功检测到回环并为全局轨迹优化增添约束;相比于传统词袋法,在回环检测准确率相同的情况下,本文方法召回率可提高21%且计算耗时减少74%;与RGB-D(red green blue-depth)SLAM算法相比,本文方法建图误差可降低29%.
文摘从同时定位与地图构建(Simultaneous Localization And Mapping,SLAM)的研究进程出发,通过回顾SLAM近三十年来的研究方法,对移动机器人SLAM的研究进行系统的总结,并指出其存在的三个关键问题.针对这三个问题,介绍了基于概率估计和基于视觉的SLAM方法,对基于概率估计的SLAM实现方法进行对比总结,并对视觉传感器的不同特性对基于视觉的SLAM方法研究进展进行阐述,随后对比分析不同方法的优缺点,讨论了视觉SLAM存在的问题.最后展望SLAM未来的发展方向.
文摘视觉SLAM(Simultaneous Localization And Mapping,同时定位与建图)是移动机器人领域的核心技术,传统视觉SLAM还难以适用于高动态场景并且地图中缺少语义信息。提出一种动态环境语义SLAM方法,用深度学习网络对图像进行目标检测,检测动态目标所在区域,对图像进行特征提取并剔除动态物体所在区域的特征点,利用静态的特征点进行位姿计算,对关键帧进行语义分割,在构建语义地图时滤除动态物体的地图点构建出无动态物体干扰的语义地图。在TUM数据集上进行实验,结果显示该方法在动态环境下可以提升88.3%位姿估计精度,并且可同时构建出无动态物体干扰的语义地图。
