ORB_SLAM实战-（rosindigo）

ORB_SLAM安装

源文件目录https://github.com/raulmur/ORB_SLAM2

安装orb_slam首先需要安装依赖库

1. 安装Pangolin

• sudo apt-get install libglew-dev
• sudo apt-get install cmake
• sudo apt-get install libpython2.7-dev
• sudo apt-get install ffmpeg libavcodec-dev libavutil-dev libavformat-dev libswscale-dev
• git clone https://github.com/stevenlovegrove/Pangolin.git

cd Pangolin
mkdir build
cd build
cmake ..
make -j

2. 安装OpenCV
   ros中自带

3. 安装Eigen3
   后续安装

4. 安装BLAS and LAPACK

sudo apt-get install libblas-dev
sudo apt-get install liblapack-dev

5. 安装DBoW2 和 g2o
   包含在orb_slam的第三方库中，后续一起安装

安装orb_slam

1. 下载软件包

cd catkin_ws/src
git clone https://github.com/raulmur/ORB_SLAM2.git

2. 编译第三方库

cd ORB_SLAM2
chmod +x build.sh
./build.sh

ORB_SLAM测试

安装USB_CAM 驱动

cd catkin_ws/src
git clone https://github.com/bosch-ros-pkg/usb_cam.git
cd ../
catkin_make

运行usb_cam 输出topic为/usb_cam/image_raw

roslaunch usb_cam usb_cam-test.launch

摄像头标定

参考ROS单目标定wiki

1. 准备标准黑白棋格盘
   • 下载黑白棋盘

• 打印棋盘（可以A4纸打印，粘贴在硬纸板上）
• 测量棋盘单元边长（A4纸的在0.025 m 左右）

2. 安装测试程序（ros）

$ rosdep install camera_calibration
$ rosmake camera_calibration

3. 启动usb_cam程序

sudo apt-get install ros-indigo-usb-cam (如果没有安装usb_cam)
roslaunch usb_cam usb-cam-test.launch

4. 启动camera_calibration

rosrun camera_calibration cameracalibrator.py --size 8x6 --square 0.025 image:=/usb_cam/image_raw camera:=/usb_cam
其中 size是黑白格的横纵点数，square是黑白格边长，image是图像节点名称，camera是相机名称。

5. 实际标定

   
   
   

   标定界面
   
   

   标定界面出现后，按照x（左右）、y（上下）、size（前后）、skew（倾斜）等方式移动棋盘，知道x,y,size,skew的进度条都变成绿色位置，此时可以按下CALIBRATE按钮，等一段时间就可以完成标定。

   
   
   

   标定就绪
   
   标定完成后，点击COMMIT按钮，最终的标定结果会在终端出现，在usb_cam的终端上会有yaml文件保存地址。
   
   

   标定结果
6. 结果转换
   转换结果如下所示：
   image_width: 640
   image_height: 480
   camera_name: usb_cam
   camera_matrix:
   rows: 3
   cols: 3
   data: [914.5937398762499, 0, 313.2995046937195, 0, 906.4439566149695, 299.4151672923101, 0, 0, 1]
   distortion_model: plumb_bob
   distortion_coefficients:
   rows: 1
   cols: 5
   data: [0.09838481350767736, 0.1181389276375996, 0.01127830741538815, 0.006633733461628469, 0]
   rectification_matrix:
   rows: 3
   cols: 3
   data: [1, 0, 0, 0, 1, 0, 0, 0, 1]
   projection_matrix:
   rows: 3
   cols: 4
   data: [933.7507934570312, 0, 315.2716618576233, 0, 0, 926.8785400390625, 300.85249210037, 0, 0, 0, 1, 0]

而在orb_slam中的格式如下，需要将上面的
camera_matrix：

camera_matrix

distortion_coefficients：

distortion_coefficients

参数值对应。其中ORB参数与Viewer参数不变。
最终的mycam.yaml文件保存在：

src/ORB_SLAM2/Examples/Monocular/mycam.yaml

    %YAML:1.0
    #--------------------------------------------------------------------------------------------
    # Camera Parameters. Adjust them!
    #--------------------------------------------------------------------------------------------

    # Camera calibration and distortion parameters (OpenCV) 
    Camera.fx: 914.5937398762499
    Camera.fy: 906.4439566149695
    Camera.cx: 313.2995046937195
    Camera.cy: 299.4151672923101

    Camera.k1: 0.09838481350767736
    Camera.k2: 0.1181389276375996
    Camera.p1: 0.01127830741538815
    Camera.p2: 0.006633733461628469
    Camera.k3: 0

    Camera.width: 640
    Camera.height: 480

    # Camera frames per second 
    Camera.fps: 30.0

    # Color order of the images (0: BGR, 1: RGB. It is ignored if images are grayscale)
    Camera.RGB: 1

    #--------------------------------------------------------------------------------------------
    # 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

运行demo

1. 环境配置

export ROS_PACKAGE_PATH=${ROS_PACKAGE_PATH}:PATH/ORB_SLAM2/Examples/ROS

2. 编译

cd src/ORB_SLAM2/Examples/ROS/ORB_SLAM2
mkdir build
cd build
cmake .. -DROS_BUILD_TYPE=Release
make -j

3. 启动demo

rosrun ORB_SLAM2 Mono /home/your_path/catkin_ws/src/ORB_SLAM2/Vocabulary/ORBvoc.txt /home/your_path/catkin_ws/src/ORB_SLAM2/Examples/Monocular/mycam.yaml

其中有两个参数，第一个参数为加载的字典，第二个参数为相机参数，更改为自身的相机参数即可。