【SLAM】Ubuntu20.04安装ROS及实时运行ORB-SLAM2

2020.12.20

暂时Ubuntu20.04的ROS Melodic不支持相机标定。

1 ROS安装

Ubuntu20.04 需要安装ROS Noetic，注意在Python3下进行安装，否则会产生一系列报错。
参考：http://wiki.ros.org/UsingPython3

（1）设置网络时间协议

设置NTP，使服务器和PC的时间误差最小。

$ sudo apt-get install -y chrony ntpdate
$ sudo ntpdate -q ntp.ubuntu.com

（2）添加ROS软件源——添加代码列表及设置公钥

$ 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

连接很慢或者连不上，可以用清华TUNA源

$    sudo sh -c '. /etc/lsb-release && echo "d{2d3b390d-f615-41d0-a830-7bbdcedbd397}eb http://mirrors.ustc.edu.cn/ros/ubuntu/ `lsb_release -cs` main" > /etc/apt/sources.list.d/ros-latest.list'
$    sudo sh -c '. /etc/lsb-release && echo "deb http://mirrors.tuna.tsinghua.edu.cn/ros/ubuntu/ `lsb_release -cs` main" > /etc/apt/sources.list.d/ros-latest.list'

（3）更新软件包索引

$ sudo apt-get update && sudo apt-get upgrade 

系统为ubuntu20.04，安装ROS Noetic 版本

$ sudo apt install ros-noetic-desktop-full -y
sudo apt install ros-kinetic-desktop-full -y

安装rqt相关功能包

$ sudo apt-get install ros-noetic-rqt

（4）初始化rosdep

$ sudo rosdep init

• 报错1：

sudo: rosdep: command not found

解决

$ sudo apt install python3-rosdep2

由于ubuntu20.04不支持python-rosdep2 报错需要下载python3-rosdep2
需要安装好依赖项，否则会会卸载ros相关的包（在python2.7环境下使用)

依赖项下载

$ sudo apt install python3-catkin-pkg
$ sudo apt install python3-rosdistro
$ sudo apt install python3-rospkg 
$ sudo apt install python3-yaml 

• 报错2：

ERROR: default sources list file already exists:
	/etc/ros/rosdep/sources.list.d/20-default.list
Please delete if you wish to re-initialize

解决

$ sudo rm /etc/ros/rosdep/sources.list.d/20-default.list

• 报错3：

ERROR: cannot download default sources list from:
https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/sources.list.d/20-default.list
Website may be down.

因为国内防火墙的问题，修改hosts文件

$ sudo gedit /etc/hosts

完成初始化后显示

Wrote /etc/ros/rosdep/sources.list.d/20-default.list
Recommended: please run

	rosdep update

后运行

$ rosdep update

*报错1

reading in sources list data from /etc/ros/rosdep/sources.list.d
ERROR: error loading sources list:
	The read operation timed out

unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml]:
	 (https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml)

最后科学上网才解决了

reading in sources list data from /etc/ros/rosdep/sources.list.d
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml
Hit https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml
Query rosdistro index https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml
Skip end-of-life distro "ardent"
Skip end-of-life distro "bouncy"
Skip end-of-life distro "crystal"
Add distro "dashing"
Add distro "eloquent"
Add distro "foxy"
Skip end-of-life distro "groovy"
Skip end-of-life distro "hydro"
Skip end-of-life distro "indigo"
Skip end-of-life distro "jade"
Add distro "kinetic"
Skip end-of-life distro "lunar"
Add distro "melodic"
Add distro "noetic"
Add distro "rolling"
updated cache in /home/chan/.ros/rosdep/sources.cache

（5）安装rosinstall

$ sudo apt-get install python-rosinstall python-rosinstall-generator python-wstool build-essential

（6）加载环境配置

$ source /opt/ros/noetic/setup.bash

自动添加环境变量

$ echo "source /opt/ros/noetic/setup.bash" >> ~/.bashrc
$ source ~/.bashrc

创建工作目录并初始化

$ mkdir -p ~/catkin_ws/src
$ cd ~/catkin_ws/src
$ catkin_init_workspace
$ cd ~/catkin_ws/
$ catkin_make
$ source ~/catkin_ws/devel/setup.bash

（7）测试安装结果

启动

$ roscore

新终端安装和打开小乌龟

$ sudo apt install ros-noetic-turtlesim
$  rosrun turtlesim turtlesim_node

另一个键盘控制小乌龟

$  rosrun turtlesim turtle_teleop_key

• 报错

Resource not found: roslaunch
ROS path [0]=/opt/ros/noetic/share/ros
ROS path [1]=/home/chan/catkin_ws/src
ROS path [2]=/opt/ros/noetic/share
The traceback for the exception was written to the log file

解决

$  sudo apt install ros-noetic-rosbash
$  sudo apt install ros-noetic-roslaunch

2 Usb_cam安装

（1）下载usb_cam源码并配置环境

$ cd catkin_ws/src
$ git clone https://github.com/bosch-ros-pkg/usb_cam.git
$ cd ..
$ catkin_make
$ source ~/catkin_ws/devel/setup.bash

• 报错1：

Could NOT find image_transport

下载

$ sudo apt-get install ros-noetic-image-transport

• 报错2：

Could NOT find camera_info_manager

下载

$ sudo apt install ros-noetic-camera-info-manager

（2）编译usb_cam

$ cd  ~/catkin_ws/src/usb_cam
$ mkdir build
$ cd build
$ cmake ..
$ make

（3）测试usb摄像头

打开新终端，运行ROS

$ roscore

回到原终端运行launch文件

$ cd ~/catkin_ws/src/usb_cam/launch
$ roslaunch usb_cam usb_cam-test.launch

• 报错1：

RLException: [usb_cam-test.launch] is neither a launch file in package [usb_cam] nor is [usb_cam] a launch file name
The traceback for the exception was written to the log file

$ source ~/catkin_ws/devel/setup.bash

• 报错2：
  缺少image_view包

ERROR: cannot launch node of type [image_view/image_view]: image_view
ROS path [0]=/opt/ros/noetic/share/ros
ROS path [1]=/home/chan/catkin_ws/src
ROS path [2]=/opt/ros/noetic/share

事实上输入命令roscd image_view和roscd cv_bridge都找不到相应的包，是cv_bridge缺失。

下载

git clone https://github.com/ros-perception/vision_opencv

找到cv_bridge文件夹，修改cmakelists.txt，改为系统自己安装的opencv版本

find_package(OpenCV 3.4 REQUIRED

将文件夹复制到工作空间~/catkin_ws/src

通过cmake编译

$ cd ~/catkin_ws/src/cv_bridge
$ mkdir build
$ cd build
$ cmake ..
$ make
$ sudo make install

同理下载编译image_view

git clone https://github.com/ros-perception/image_pipeline

复制image_view进行编译
打开image_view中的CmakeLists.txt文件进行修改

在find_package前面添加

set(cv_bridge_DIR /usr/local/share/cv_bridge/cmake)  

Launch文件video_device设置中，笔记本电脑自带摄像头为video0，更换为usb摄像头需要更改，一般为video1。

可运行以下命令查看类型

$ ls /dev/video*

正常情况可打开摄像头

3 相机标定

使用OpenCV进行图像处理，需要对相机进行校准。镜头和图像传感器在组装时可能有偏离，包括图像中心（image center）与主点（principal point）的偏差和传感器的倾斜度等。校准（calibration）的目的是查找相机的固有参数。

（1）准备黑白棋盘格

Matlab官方相机标定黑白棋盘格网址：
http://www.vision.caltech.edu/bouguetj/calib_doc/htmls/pattern.pdf

打印在A4上，每个棋盘格的边长为0.028m。
黑白棋盘格是由9×7的黑白格组成，使用的是内部交点即8×6的角点。

（2）安装相机校准软件包

原本用ubuntu16.04可以安装uvc_camera软件包，但是现在还没有noetic版本的包
https://index.ros.org/p/uvc_camera/github-ros-drivers-camera_umd/

因此采用usb_camera作为节点。

$ sudo apt install ros-noetic-usb-cam

安装相机校准软件包

$ sudo apt install ros-noetic-camera-calibration

（3）运行ROS

$ roscore 

（4）打开新终端，启动usb_camera节点

$ rosrun usb_camera usb_camera_node

这里只能看到摄像头打开并不会看到图像，如果想要看下当前的图像可以使用 image_view，因为 usb_cam 默认发布 /usb_cam/image_raw 这样的 topic，topic查看命令为rostopic list

启动usb_camera可视节点

$ rosrun image_view image_view image:=/usb_cam/image_raw

可看到没有检测到相机校准配置文件。

[ WARN] [1605509617.183192743]: Camera calibration file /home/chan/.ros/camera_info/head_camera.yaml not found.

查看默认的相机信息，显示为默认值

$ rostopic echo /camera_info

WARNING: topic [/camera_info] does not appear to be published yet

（5）打开新的终端，启动GUI

$ rosrun camera_calibration cameracalibrator.py –size 8×6 –square 0.028 image:=/image_raw

标定过程中左右，上下，前后，对角方向前后倾斜标定板，这样使得右边X，Y， Size, Skew变成绿色后，CALIBRATE按钮变为蓝色，然后点击。等待三个按钮都可以点击，依次点击SAVE(保存)和COMMIT(提交)到相机配置文件中。即可将标定结果保存至本地。

点击SAVE之后：(‘Wrote calibration data to’, ‘/tmp/calibrationdata.tar.gz’)

https://answers.ros.org/question/363942/camera_calibration-does-not-work-ros-noetic/

（6）若点击COMMIT出现：

raise ServiceException(“service [%s] unavailable”%self.resolved_name)
rospy.service.ServiceException: service [/camera/set_camera_info] unavailable

需要自行将标定参数移动至：

~/.ros/camera_info
$ cd /tmp
$ tar -zxvf calibrationdata.tar.gz
$ mkdir /.ros/camera_info
$ sudo cp ost.yaml ~/.ros/camera_info
$ cd ~/.ros/camera_info
$ sudo mv ./ost.yaml ./head_camera.yaml

（7）打开head_camera.yaml文件，将camera_name改成head_camera

（4）重新运行usb摄像头
打开新终端，运行ROS

$ roscore

回到原终端运行launch文件

$ cd launch
$ roslaunch usb_cam usb_cam-test.launch

[ WARN] [1605509617.528102354]: unknown control 'focus_auto'

显示unknown control 'focus_auto'，原因是相机不可以自动对焦，可以忽略

4 编译ORB_SLAM2 ROS例子

（1）编译g2o

$ cd ~/ORB_SLAM2/Thirdparty/g2o
$ mkdir build
$ cmake ..
$ make

（2）编译DBoW2

$ cd ~/ORB_SLAM2/Thirdparty/ DBoW2
$ mkdir build
$ cmake ..
$ make

（3）编译ORB_SLAM2

$ cd ~/ORB_SLAM2
$ cd build  // 由于已经新建build文件夹，若无，则mkdir build
$ cmake ..
$ make

（4）编译ROS的example

$ cd ~/ORB_SLAM2/Examples/ROS/ORB_SLAM2
$ mkdir build
$ cd build
$ cmake ..
$ make 

5 ORB_SLAM2在ROS实时运行

（1）打开第一个终端，运行roscore

$ roscore

（2）打开第二个终端，运行usb_cam

$ cd catkin_ws/src/usb_cam/launch
$ source ~/catkin_ws/devel/setup.bash
$ roslaunch usb_cam usb_cam-test.launch

（3）打开第三个终端，运行Mono文件
格式如下：

$ rosrun ORB_SLAM2 Mono PATH_TO_VOCABULARY PATH_TO_SETTINGS_FILE

运行：

$ rosrun ORB_SLAM2 Mono /home/chan/ORB_SLAM2/Vocabulary/ORBvoc.txt  /home/chan/ORB_SLAM2/Examples/ROS/ORB_SLAM2/Asus.yaml /camera/image_raw:=/usb_cam/image_raw


第一次运行后，创建82个地图点，后初始化出错。
重置后，检测到110地图点。


第二次运行后检测到70个地图点，移动摄像机后显示TRACK LOST，需要重定位。重定位后检测到130个地图点。实时运行的响应度较低


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参考：
[https://blog.csdn.net/pengrui18/article/details/88958487](https://blog.csdn.net/pengrui18/article/details/88958487)
[https://blog.csdn.net/fb_941219/article/details/105705759](https://blog.csdn.net/fb_941219/article/details/105705759)
[https://answers.ros.org/question/359998/camera-calibration-on-ros-noetic-calibration-display-with-video-is-flickering/](https://answers.ros.org/question/359998/camera-calibration-on-ros-noetic-calibration-display-with-video-is-flickering/)