Intel Realsense D435i相机标定

• 相机内参标定

  • 采用Kalibr工具：https://github.com/ethz-asl/Kalibr
  • 基于环境镜像：https://github.com/ethz-asl/kalibr/wiki/installation

    • docker pull stereolabs/kalibr

    • #!/bin/sh
      
      data_dir=$1
      
      if [ ! -d "$data_dir" ]; then
        echo "data directory does not exist: $data_dir"
        exit 1
      fi
      
      xhost +local:root;
      docker run -it -e DISPLAY -e QT_X11_NO_MITSHM=1 -v /tmp/.X11-unix:/tmp/.X11-unix:rw -v $data_dir:/root/data stereolabs/kalibr:kinetic /bin/bash -c "cd /root/data; /bin/bash"
      xhost -local:root;
      

    • chmod +x run_kalibr.sh

    • ./run_kalibr.sh ， where  is the path to the directory on your computer which contains your calibration bag file

    • 安装pyx：

      • echo ' deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse
        deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse
        deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse
        deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse
        deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse
        deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse
        deb http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse
        deb-src http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse
        deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
        deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse' > /etc/apt/sources.list
        

      • apt-get install -y python-pyx

  • 标定步骤

    • 生成棋盘格

      • # 生成棋盘格标定板 type：checkerboard或apriltag
        # --nx [NUM_COLS] --ny [NUM_ROWS] --tsize [TAG_WIDTH_M] --tspace [TAG_SPACING_PERCENT]
        kalibr_create_target_pdf --type checkerboard --nx 6 --ny 7 --csx 0.030 --csy 0.030

    • 编写checkerboard.yaml文件

      • target_type: 'checkerboard' #gridtype
        targetCols: 6               #number of internal chessboard corners
        targetRows: 7               #number of internal chessboard corners
        rowSpacingMeters: 0.029     #size of one chessboard square [m]
        colSpacingMeters: 0.029     #size of one chessboard square [m]
        

    • 系统下录制bag包（基于ros安装、realsense sdk安装好的前提下）

      • mkdir ~/temp/data && cd ~/temp/data
      • roslaunch realsense2_camera rs_camera.launch

      • rosrun topic_tools throttle messages /camera/color/image_raw 4.0 /color

      • rosbag record -O camd435i /color（过程中打开rviz查看）

    • 标定

      • docker cp camd435i 容器工作目录

      • docker cp checkerboard.yaml 容器工作目录

      • 进入到上述容器工作目录

      • kalibr_calibrate_cameras --target ~/kalibr_ws/src/Kalibr/data/checkerboard.yaml --bag ~/kalibr_ws/src/Kalibr/data/camd435i.bag --models pinhole-equi --topics /color --show-extractio --approx-sync 0.04

      • 报错：Cameras are not connected through mutual observations, please check the dataset. Maybe adjust the approx. sync. tolerance

        • # 注释/kalibr_workspace/src/Kalibr/aslam_offline_calibration/kalibr/python/kalibr_calibrate_cameras文件中下面这几行，201行左右
          if not graph.isGraphConnected():
              obsdb.printTable()
              print "Cameras are not connected through mutual observations, please check the dataset. Maybe adjust the approx. sync. tolerance."
              graph.plotGraph()
              sys.exit(-1)
          

• 相机外参标定