porting pointcoud_to_pcd to ros2

[Ar-Ray-code]

I needed the ROS 2 version of pointcoud_to_pcd, so I will port it and submit a PR.
Please review.

Depends

• ROS 2 Humble (on Ubuntu22.04 LTS, x86-64)

Usage

• subscriber topic (pointcloud2) : /cloud_in
• prefix : abc_
• fixed_frame (central frame_id) : base_link

ros2 run pcl_ros pointcloud_to_pcd --ros-args -r input:=/cloud_in -p prefix:=abc_ -p fixed_frame:=base_link

How to check exported pcd file

pcl_viewer <path to .pcd file>

Thank you.

[SteveMacenski]

LGTM from a quick glance. From your testing image I assume this works fine

[SteveMacenski]

Were there tests associated with this as well?

Otherwise, give this a week and if no other maintainers chime in, ping me again and I'll merge it

[remco-r]

builds for humble (not for foxy)
features tested

• prefix
• compresed
• binary
• prefix
• fixed_frame

ros2 run pcl_ros pointcloud_to_pcd --ros-args -r input:=os_node/points -p prefix:=abc_ -p binary:=true -p compressed:=true -p fixed_frame:=base_link

Everything works except fixed_frame feature because my (ouster) lidar frame is on tf_static i get the following error.

[WARN] [1712221819.952296406] [transform_listener_impl_556e0f932ee0]: New publisher discovered on topic '/tf_static', offering incompatible QoS. No messages will be sent to it. Last incompatible policy: DURABILITY_QOS_POLICY
[ERROR] [1712221820.239036841] [pointcloud_to_pcd]: Transform error: "os_sensor" passed to lookupTransform argument source_frame does not exist. 

[Ar-Ray-code]

builds for humble (not for foxy) features tested

• prefix
• compresed
• binary
• prefix
• fixed_frame

ros2 run pcl_ros pointcloud_to_pcd --ros-args -r input:=os_node/points -p prefix:=abc_ -p binary:=true -p compressed:=true -p fixed_frame:=base_link

Everything works except fixed_frame feature because my (ouster) lidar frame is on tf_static i get the following error.

[WARN] [1712221819.952296406] [transform_listener_impl_556e0f932ee0]: New publisher discovered on topic '/tf_static', offering incompatible QoS. No messages will be sent to it. Last incompatible policy: DURABILITY_QOS_POLICY
[ERROR] [1712221820.239036841] [pointcloud_to_pcd]: Transform error: "os_sensor" passed to lookupTransform argument source_frame does not exist. 

Thank you for your testing.

fixed_frame is an option that can be used when the sensor is connected to another tf.
For example, the following command broadcasts a relative position with x=2, yaw=90deg.

ros2 run tf2_ros static_transform_publisher 2 0 0 0 0 0.707 0.707 base_link velodyne

I would consider implementing the following: if tf cannot be obtained, a warning is displayed and the fixed_frame option is ignored. <- done

[Ar-Ray-code]

I also added the rgb option because when I tested with velodyne we could not save in RGB. (Default is false)

[SteveMacenski]

@remco-r let me know if that resolves your concern

[remco-r]

@SteveMacenski

• The fixed_frame issue is just an observation. Its a ros2 and tf issue though, and not related to this PR. So concern resolved
• The new RGB + use_transform features added in the last two commits I havent tested, but the code looks good.