hri_fullbody

Overview

:warning: some of the links are yet to be updated and may be pointing to the original ROS page. As soon as all the involved components will be officially documented for ROS 2 as well, we will update this document.

hri_fullbody is a ROS4HRI-compatible 3D body pose estimation node.

It is built on top of Google Mediapipe 3D body pose estimation.

The node provides the 3D pose estimation for the detected humans in the scene, implementing a robust solution to self-occlusions.

This node can be used in two different modes: single body and multi-body. In the former case, the node performs the whole body detection pipeline, publishing information under the ROS4HRI naming convention regarding the body id (on the /humans/bodies/tracked topic), the body bounding box, and the jointstate of the body's skeleton. In the latter, the node only publishes jointstate information, expecting body detection to be performed by another node and subscribing to /humans/bodies/tracked to read the ids of the currently tracked bodies.

These two modes are required since Mediapipe body estimation is not able to estimate more than one body pose per frame. Therefore, in case we want more than one body pose estimated, the adopted strategy is to rely on some other package implementing a human body detection (and tracking in the best case) algorithm. Such package should provide the hri_fullbody detect node the IDs of the detected bodies and the relative images, cropped from the original image following the detected bounding boxes.

To estimate the body position, the node does not need a RGB-D camera, only RGB is required. However, using RGB-D camera provides a more accurate depth estimation.

Important: to estimate the body depth without using a depth sensor, a calibrated RGB camera is required. You can follow this tutorial to properly calibrate your camera.

Launch

ros2 launch hri_fullbody hri_fullbody_with_args.launch.py <parameters>

ROS API

Parameters

Node parameters:

• single_body (default: True): whether or not running in single body mode (see above for the single body vs multi-body modes).
• use_depth (default: False): whether or not to rely on depth images for estimating body movement in the scene. When this is False, the node estimates the body position in the scene solving a P6P problem for the face and approximating the position from this, using pinhole camera model geometry.
• stickman_debug (default: False): whether or not to publish frames representing the body skeleton directly using the raw results from mediapipe 3D body pose estimation. These debug frames are not oriented to align with the body links (ie, only the 3D location of the frame is useful).
• human_description_<body_id> (read-only): the URDF generated for body_<body_id>. The node generates a URDF for each detected body and uses them to perform kinematically-consistent 3D body pose estimation.

hri_fullbody.launch parameters:

• single_body (default: True): equivalent to single_body node parameter.
• use_depth (default: False): equivalent to use_depth node parameter.
• stickman_debug (default: False): equivalent to stickman_debug node parameter.
• rgb_camera (default: ): rgb camera topics namespace.
• rgb_camera_topic (default: $(arg rgb_camera)/image_raw): rgb camera raw image topic.
• rgb_camera_info (default: $(arg rgb_camera)/camera_info): rgb camera info topic.
• depth_camera (default: ): depth camera topics namespace.
• depth_camera_topic (default: $(arg depth_camera)/image_rect_raw): depth camera rectified raw image topic.
• depth_camera_info (default: $(arg depth_camera)/camera_info): depth camera info topic.

Topics

hri_fullbody follows the ROS4HRI conventions (REP-155). In particular, refer to the REP to know the list and position of the 2D/3D skeleton points published by the node.

Subscribed topics

• /camera_info (sensor_msgs/CameraInfo): rgb camera meta information
• /depth_image (sensor_msgs/Image): depth image used to estimate the 3D body position with respect to the camera.
• /depth_info (sensor_msgs/CameraInfo): depth camera meta information

Single body mode only:

• /image (sensor_msgs/Image): rgb image, processed for body detection and 3D body pose estimation.

Multi-body mode only:

• /humans/bodies/tracked (hri_msgs/IdsList): list of the bodies currently detected.
• /humans/bodies/<body_id>/cropped (sensor_msgs/Image): image used to estimate the 3D body pose.
• /humans/bodies/<body_id>/roi (hri_msgs/NormalizedRegionOfInterest2D): body bounding box in normalized image coordinates.

Published topics

• /humans/bodies/<body_id>/skeleton2d (hri_msgs/Skeleton2D): detected 2D skeleton points.
• /humans/bodies/<body_id>/joint_states (sensor_msgs/JointState): skeleton joints state.
• /humans/bodies/<body_id>/position: (geometry_msgs/PointStamped): filtered body position, representing the point between the hips of the tracked body. Only published when use_depth = True.
• /humans/bodies/<body_id>/velocity: (geometry_msgs/TwistStamped): filtered body velocity. Only published when use_depth = True.

Single body mode only:

• /humans/bodies/tracked (hri_msgs/IdsList): list of the bodies currently detected. There will be only one body in the list.
• /humans/bodies/<body_id>/roi (hri_msgs/NormalizedRegionOfInterest2D): body bounding box in normalized image coordinates.

Visualization

It is possible to visualize the results of the body pose estimation in rviz using the hri_rviz Skeleton plugin. A visualization example is reported in the image above.