open3d_conversions

This package provides functions that can convert pointclouds and images from ROS to Open3D and vice-versa.

Dependencies

• Eigen3
• Open3D

System Requirements

• Ubuntu 20.04+: GCC 5+

Installation

Open3D

• Instructions to setup Open3D can be found here.

open3d_conversions

• In case you are building this package from source, time taken for the conversion functions will be much larger if it is not built in Release mode.

Pointcloud Conversion

There are two pointcloud conversion functions provided in this library:

void open3d_conversions::open3dToRos(
  const open3d::geometry::PointCloud & pointcloud,
  sensor_msgs::msg::PointCloud2 & ros_pc2, 
  std::string frame_id = "open3d_pointcloud");

void open3d_conversions::rosToOpen3d(
  const sensor_msgs::msg::PointCloud2::SharedPtr & ros_pc2,
  open3d::geometry::PointCloud & o3d_pc, 
  bool skip_colors=false);

• As Open3D pointclouds only contain points, colors and normals, the interface currently supports XYZ, XYZRGB pointclouds. XYZI pointclouds are handled by placing the intensity value in the colors_.
• On creating a ROS pointcloud from an Open3D pointcloud, the user is expected to set the timestamp in the header and pass the frame_id to the conversion function.

Image Conversion

There are four image conversion functions provided in this library:

void open3dToRos(
  const open3d::geometry::Image & o3d_img,
  sensor_msgs::msg::Image & ros_img,
  std::string encoding,
  std::string frame_id = "open3d_image");

void open3dToRos(
  const open3d::camera::PinholeCameraIntrinsic & intrinsic,
  sensor_msgs::msg::CameraInfo & camera_info,
  std::string frame_id = "open3d_image");

void rosToOpen3d(
  const sensor_msgs::msg::Image & ros_img,
  open3d::geometry::Image & o3d_img);

void rosToOpen3d(
  const sensor_msgs::msg::CameraInfo & camera_info,
  open3d::camera::PinholeCameraIntrinsic & intrinsic);

Additionally, two explicit move-only versions of the image conversions are provided for efficiency:

void moveOpen3dToRos(
  open3d::geometry::Image && o3d_img,
  sensor_msgs::msg::Image & ros_img,
  std::string encoding,
  std::string frame_id = "open3d_image");

void moveRosToOpen3d(
  sensor_msgs::msg::Image && ros_img,
  open3d::geometry::Image & o3d_img);

• As Open3D only stores camera info as a pinhole camera model, distorsion information cannot be inferred from an Open3D -> ROS conversion. Such a conversions sets the distorsion model to “plumb_bob” with all five D parameters equal to zero.

Documentation

Documentation can be generated using Doxygen and the configuration file by executing doxygen Doxyfile in the package.

Contact

Feel free to contact us for any questions:

• Pranay Mathur
• Nikhil Khedekar
• Kostas Alexis