visual_compass is the navigation node which provides the information about the robot rotation around the z-axis in the horizontal plane (yaw) from the spherical or cylindrical panorama images. It serves as a computationally undemanding alternative for the visual odometry. It depends on the ROS build-in OpenCV.

ROS API

ROS topics

Subscribes to:
"/viz/pano/image" [sensor_msgs/Image] Panoramic camera images

Publishes to:
"/vcompass_pose" [nav_msgs::Odometry] Standard ROS odometry message without covariance matrix. Provides only quaternion with respect to the yaw angle and information about angular twist. Other fields are zero.

ROS parameters

Reads the following parameters from the parameter server:

• "compass_image" [string] defines the input panorama topic
• "compass_output_topic" [string] defines the output odometry topic
• "compass_textout" [bool] sets the text output to the console on

ROS services

This node does not provide any ROS services.

Command-line tools

In the following available '.launch' files are briefly described.

"visual_compass.launch" - sets the ROS parameters related to the visual_compass and launches the main node.
"visual_compass_BAG.launch" - does the same as visual_compass.launch plus sets the 'image_transport' to republish the compressed camera topic (commonly recorded by the ROSBAG record) to the raw format.