point_cloud_transport

point_cloud_transport

(opens in a new tab)

Description

point_cloud_transport (opens in a new tab) is a ROS 2 (opens in a new tab) package for subscribing to and publishing PointCloud2 (opens in a new tab) messages via different transport layers. E.g. it can provide support for transporting point clouds in low-bandwidth environment using Draco (opens in a new tab) compression library.

Usage

point_cloud_transport (opens in a new tab) can be used to publish and subscribe to PointCloud2 (opens in a new tab) messages. At this level of usage, it is similar to using ROS 2 Publishers and Subscribers. Using point_cloud_transport (opens in a new tab) instead of the ROS 2 primitives, however, gives the user much greater flexibility in how point clouds are communicated between nodes.

For complete examples of publishing and subscribing to point clouds using point_cloud_transport (opens in a new tab), see Tutorial (opens in a new tab).

C++

Communicating PointCloud2 messages using point_cloud_transport (opens in a new tab):

#include <rclcpp/node.hpp>
#include <point_cloud_transport/point_cloud_transport.hpp>

void Callback(const sensor_msgs::msg::PointCloud2::ConstSharedPtr& msg)
{
  // ... process the message
}

auto node = std::make_shared<rclcpp::Node>();
point_cloud_transport::PointCloudTransport pct(*node);
point_cloud_transport::Subscriber sub = pct.subscribe("in_point_cloud_base_topic", 1, Callback);
point_cloud_transport::Publisher pub = pct.advertise("out_point_cloud_base_topic", 1);

Alternatively, you can use point_cloud_transport outside of ROS2.

#include <sensor_msgs/msg/point_cloud2.hpp>

#include <point_cloud_transport/point_cloud_codec.hpp>

point_cloud_transport::PointCloudCodec codec;

sensor_msgs::msg::PointCloud2 msg;
// ... do some cool pointcloud generation stuff ...

// untyped version (outputs an rclcpp::SerializedMessage)
rclcpp::SerializedMessage serialized_msg;
bool success = codec.encode("draco", msg, serialized_msg);

// OR

// typed version (outputs whatever message your selected transport returns,
// for draco that is a point_cloud_interfaces::msg::CompressedPointCloud2)
point_cloud_interfaces::msg::CompressedPointCloud2 compressed_msg;
bool success = codec.encode("draco", msg, compressed_msg);

Republish rclcpp component

We provide a process to republish any topic speaking in a given transport to a different topic speaking a different transport. e.g. have it subscribe to a topic you recorded encoded using draco and publish it as a raw, decoded message

ros2 run point_cloud_transport republish --ros-args -p in_transport:=raw -p out_transport:=draco --remap in:=input_topic_name --remap out:=ouput_topic_name

Python

The functionality of point_cloud_transport is also exposed to python via pybind11 and rclpy serialization.

Please see publisher.py (opens in a new tab) and subscriber.py (opens in a new tab) for example usage.

Whitelist point cloud transport

This allows you to specify plugins you do want to load (a.k.a. whitelist them).

ros2 run point_cloud_transport_tutorial my_publisher --ros-args -p pct.point_cloud.enable_pub_plugins:=["point_cloud_transport/zlib"]

Known transports

• draco_point_cloud_transport (opens in a new tab): Lossy compression via Google
• zlib_point_cloud_transport (opens in a new tab): Lossless compression via Zlib compression.
• zstd_point_cloud_transport (opens in a new tab): Lossless compression via Zstd compression.
• Did you write one? Don't hesitate and send a pull request adding it to this list!

Authors

ROS 1 Version:

• Jakub Paplhám - Initial work - paplhjak (opens in a new tab)
• Ing. Tomáš Petříček, Ph.D. - Supervisor - tpet (opens in a new tab)
• Martin Pecka - Maintainer - peci1 (opens in a new tab)

ROS 2 Version:

• John D'Angelo - Port to ROS 2 and Maintainer - john-maidbot (opens in a new tab)
• Alejandro Hernández - Port to ROS 2 and Maintainer - ahcorde (opens in a new tab)

License

This project is licensed under the BSD License - see the LICENSE (opens in a new tab) file for details.

Acknowledgments

• image_transport (opens in a new tab) - Provided template of plugin interface
• Draco (opens in a new tab) - Provided compression functionality

Support

For questions/comments please email the maintainer mentioned in package.xml.

If you have found an error in this package, please file an issue at: github.com (opens in a new tab)

Patches are encouraged, and may be submitted by forking this project and submitting a pull request through GitHub. Any help is further development of the project is much appreciated.