sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'  sudo apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654  sudo apt update sudo apt install ros-melodic-desktop-full(时间稍长，需一会儿) ！复制完全不丢东西！ ------------------------------------------------------------------------ sudo rosdep init 错误：找不到命令 解决：sudo apt install python-rosdep2 ------------------------------------------------------------------------ 

rosdep update 出现 timed out  超时问题 

解决方案：解决方案 涉及到的rosdistro文件 rosdistro 提取码: b3hb

sudo apt-get install python-rosinstall source /opt/ros/melodic/setup.bash 

创建并初始化工作目录ROS使用一个名字catkin的ROS用户需要创建和初始化专用建筑系统。catkin工作目录，如下所示。除非用户创建新的工作目录，否则此设置只需设置一次。

mkdir -p ~/catkin_ws/src cd ~/catkin_ws/src catkin_init_workspace cd ~/catkin_ws/ catkin_make sudo apt install net-tools gedit ~/.bashrc 在弹出文本的最后添加以下两句话 source /opt/ros/melodic/setup.bash source ~/catkin_ws/devel/setup.bash 保存 source ~/.bshrc

进行测试：

roscore

出现错误：没发现roscore
解决：
sudo apt-get install ros-melodic-desktop

重新打开三个终端：

roscore

rosrun turtlesim turtlesim_node

rosrun turtlesim turtle_teleop_key

鼠标点击最后一个终端，按方向键小海龟可以移动

1.安装pcl点云库，大致按这个教程安装就可以 点云安装

2.下载 高翔博士修改后的orbslam2

git clone https://github.com/gaoxiang12/ORBSLAM2_with_pointcloud_map.git

我按照网上教程稍微自己稍微修改了的

复制这段内容后打开百度网盘手机App，操作更方便哦
链接：https://pan.baidu.com/s/18T6kNhHFRxoxiKYo3o3rEg 
提取码：i3CB --来自百度网盘超级会员V5的分享

如果下载高翔原版代码，解压zip，将第一个文件夹中文件，复制替换进 解压后 文件夹中 的ORB_SLAM2_modified

3.编译g2o 解压后找到g2o_with_orbslam2文件夹 如果下载我的不需要修改，高翔原版需要改动一下 1）分别对文件夹下cmakelist和g20下的cmakelist对相应语句进行注释 主文件夹下 g20下的 注释后保存

2）修改g2o/types/slam2d/edge_se2_pointxy_bearing.cpp

原代码：t.setRotation(t.rotation().angle()+_measurement);

修改后：t.setRotation((Eigen::Rotation2Dd)(t.rotation().angle()+_measurement));  

3）修改/g2o_with_orbslam2/g2o/solvers/eigen/linear_solver_eigen.h

原代码：typedef Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, SparseMatrix::Index> PermutationMatrix;

修改后：typedef Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic, SparseMatrix::StorageIndex> PermutationMatrix;

保存后，回到g2o_with_orbslam2主文件夹下

mkdir build
cmake ..
make -j8
sudo make install

4.进入ORB_SLAM2_modified文件夹 高翔原版没有ORBvoc.txt.tar.gz需要自行下载，而后将其放置于Vocabulary文件夹下，顺手解压一下

ORBvoc.txt.tar.gz

修改文件夹中的cmakelist，将opencv和eigen3修改为自己电脑安装的版本，我前边提供的eigen3为3.2.10，我安装时ros自带的3.2的opencv。如果不清楚可以进行查询

pkg-config --modversion opencv

修改cmakelist为对应版本 来到/ORB_SLAM2_modified/Examples/ROS/ORB_SLAM2/CMakeLists.txt 查看这 5 处是否正确，并也将对应的库版本号修改为自己安装的版本 修改后，删除 /ORB_SLAM2_modified/build, /ORB_SLAM2_modified/Thirdparty/DBoW2/build /ORB_SLAM2_modified/Thirdparty/g2o/build 删掉三个 build 文件夹

在ORB_SLAM2_modified下右键打开终端

cd ORB_SLAM2_modified/Thirdparty/DBoW2
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
make 

从新在ORB_SLAM2_modified下右键打开终端

mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
make -j8

数据集测试，数据集需自行下载，我提供的代码中dataset中有两个下载好直接能用的数据集 如果自己下载需要对rgbd和depth进行关联

python associate.py rgb.txt depth.txt > associations.txt

示例命令 ./Example/RGB-D/rgbd_tum　Vocabulary/ORBvoc.txt　path_to_settings　path_to_sequence path_to_association 在ORB_SLAM2_modified打开终端执行

./Examples/RGB-D/rgbd_tum Vocabulary/ORBvoc.txt Examples/RGB-D/TUM1.yaml datasets/rgbd_dataset_freiburg1_xyz  datasets/rgbd_dataset_freiburg1_xyz/association.txt

./Examples/RGB-D/rgbd_tum Vocabulary/ORBvoc.txt Examples/RGB-D/TUM1.yaml datasets/rgbd_dataset_freiburg1_room  datasets/rgbd_dataset_freiburg1_room/association.txt

高翔原版似乎没有地图保存和彩色，如果需要保存地图，或者地图不是彩色，请参考文章中间部分 保存地图，地图不是彩色

保存的点云在主文件夹下，名称vslam.pcd，当前文件夹打开终端

pcl_viewer vslam.pcd  (查看点云)

Ubuntu18.04 + ROS melodic 安装使用 RealSenseD435i

Ubuntu18.04下安装RealSense D435i相机的SDK和ROS包

1.来到ORB_SLAM2_modified文件夹 在打开的文本最后添加你的ROS路径，保存

gedit ~/.bashrc
export ROS_PACKAGE_PATH=${ROS_PACKAGE_PATH}:/你的目录/ORB_SLAM2_modified/Examples/ROS

保存后在终端输入

source ~/.bashrc

chmod +x build_ros.sh
./build_ros.sh

2.修改ORB_SLAM2_modified/Examples/ROS/ORB_SLAM2/src/ros_rgbd.cc文件，把rgb_topic和depth_topic订阅话题修改为

 "/camera/color/image_raw";
 "/camera/aligned_depth_to_color/image_raw";

ORB_SLAM2_modified下从新打开终端

chmod +x build.sh 
./build.sh
chmod +x build_ros.sh
./build_ros.sh

从新打开终端，查看内参

roscore
roslaunch realsense2_camera rs_rgbd.launch 
rostopic echo /camera/color/camera_info

没有rs_rgbd.lunch 解决：sudo apt-get install ros-melodic-rgbd-launch 终端中显示的K,为参数，其中 K = [fx 0 cx 0 fy cy 0 0 1 ] 基线50mm

修改参数，得到一个新的D435i.yaml

%YAML:1.0
 
#--------------------------------------------------------------------------------------------
# Camera Parameters. Adjust them!
#--------------------------------------------------------------------------------------------
 
# Camera calibration and distortion parameters (OpenCV) 
Camera.fx: 909.559875
Camera.fy: 909.740478
Camera.cx: 645.366455
Camera.cy: 366.805908

Camera.k1: 0.0
Camera.k2: 0.0
Camera.p1: 0.0
Camera.p2: 0.0
Camera.p3: 0.0

Camera.width: 640
Camera.height: 480
# Camera frames per second 
Camera.fps: 30.0

# IR projector baseline times fx (aprox.)
# bf = baseline (in meters) * fx, D435i的 baseline = 50 mm 
Camera.bf: 50.0
 
# Color order of the images (0: BGR, 1: RGB. It is ignored if images are grayscale)
Camera.RGB: 1
 
# Close/Far threshold. Baseline times.
ThDepth: 40.0
 
# Deptmap values factor
DepthMapFactor: 1000.0
 
#--------------------------------------------------------------------------------------------
# ORB Parameters
#--------------------------------------------------------------------------------------------
 
# ORB Extractor: Number of features per image
ORBextractor.nFeatures: 1000
 
# ORB Extractor: Scale factor between levels in the scale pyramid 
ORBextractor.scaleFactor: 1.2
 
# ORB Extractor: Number of levels in the scale pyramid 
ORBextractor.nLevels: 8
 
# ORB Extractor: Fast threshold
# Image is divided in a grid. At each cell FAST are extracted imposing a minimum response.
# Firstly we impose iniThFAST. If no corners are detected we impose a lower value minThFAST
# You can lower these values if your images have low contrast 
ORBextractor.iniThFAST: 20
ORBextractor.minThFAST: 7
 
#--------------------------------------------------------------------------------------------
# Viewer Parameters
#--------------------------------------------------------------------------------------------
Viewer.KeyFrameSize: 0.05
Viewer.KeyFrameLineWidth: 1
Viewer.GraphLineWidth: 0.9
Viewer.PointSize:2
Viewer.CameraSize: 0.08
Viewer.CameraLineWidth: 3
Viewer.ViewpointX: 0
Viewer.ViewpointY: -0.7
Viewer.ViewpointZ: -1.8
Viewer.ViewpointF: 500
 
PointCloudMapping.Resolution: 0.01
meank: 50
thresh: 2.0

运行，打开三个终端

roscore
roslaunch realsense2_camera rs_rgbd.launch
rosrun ORB_SLAM2 RGBD Vocabulary/ORBvoc.txt Examples/RGB-D/D435i.yaml

运行视频b站：【视觉slam Orbslam2+D435i 稠密点云，记录-哔哩哔哩 过程中会遇到各种问题，需要大家自己解决喽，因为问题各不相同，所以大家就自行搜索解决，我只记录了一下自己从配置到运行的大致过程。

我遇到最多的问题是这个： 核心转储：核心转储解决