pbstream生成ply和pcd并可视化

保存.pbstream地图-.pbstream地图转pgm，yaml文件，参考此处

对于.pbstream文件生成ply及pcd文件如下：
bag包对应生成的.pbstream文件(下面代码中的*请自行改成自己的文件名)，

roslaunch cartographer_ros assets_writer_my_3d.launch bag_filenames:=/home/hyper/Downloads/***.bag pose_graph_filename:=/home/hyper/Downloads/***.pbstream

执行完此句，会生成对应的ply文件，ply转pcd如下：

pcl_ply2pcd ***.bag_points.ply ***.pcd

可视化pcd点云可用如下命令：

pcl_viewer ***.pcd

对于assets_writer_my_3d.launch文件如下：

<launch>
  <node name="cartographer_assets_writer" pkg="cartographer_ros" required="true"
      type="cartographer_assets_writer" args="
          -configuration_directory $(find cartographer_ros)/configuration_files
          -configuration_basename assets_writer_my_3d.lua
          -urdf_filename $(find cartographer_ros)/urdf/my_backpack_3d.urdf
          -bag_filenames $(arg bag_filenames)
          -pose_graph_filename $(arg pose_graph_filename)"
      output="screen">
  </node>
</launch>

launch文件里对应的assets_writer_my_3d.lua文件如下：

VOXEL_SIZE = 5e-2

include "transform.lua"

options = {
  tracking_frame = "base_link",
  pipeline = {
    {
      action = "min_max_range_filter",
      min_range = 1.,
      max_range = 60.,
    },
    {
      action = "dump_num_points",
    },
    {
      action = "fixed_ratio_sampler",
      sampling_ratio = 0.01,
    },

    {
      action = "write_ply",
      filename = "points.ply"
    },
	
    -- Gray X-Rays. These only use geometry to color pixels.
    {
      action = "write_xray_image",
      voxel_size = VOXEL_SIZE,
      filename = "xray_yz_all",
      transform = YZ_TRANSFORM,
    },
    {
      action = "write_xray_image",
      voxel_size = VOXEL_SIZE,
      filename = "xray_xy_all",
      transform = XY_TRANSFORM,
    },
    {
      action = "write_xray_image",
      voxel_size = VOXEL_SIZE,
      filename = "xray_xz_all",
      transform = XZ_TRANSFORM,
    },

    -- Now we recolor our points by frame and write another batch of X-Rays. It
    -- is visible in them what was seen by the horizontal and the vertical
    -- laser.
    {
      action = "color_points",
      frame_id = "world",
      color = { 255., 0., 0. },
    },

    {
      action = "write_xray_image",
      voxel_size = VOXEL_SIZE,
      filename = "xray_yz_all_color",
      transform = YZ_TRANSFORM,
    },
    {
      action = "write_xray_image",
      voxel_size = VOXEL_SIZE,
      filename = "xray_xy_all_color",
      transform = XY_TRANSFORM,
    },
    {
      action = "write_xray_image",
      voxel_size = VOXEL_SIZE,
      filename = "xray_xz_all_color",
      transform = XZ_TRANSFORM,
    },
  }
}

return options

最主要的就是修改lua文件中的tracking_frame和frame_id。