README

ROS UMich Apriltag detector package

This repository has ROS2 components for detecting Apriltags using the UMich Apriltag library.

Note that this package also provides a plugin that works with pluginlib, meaning you can load this detector directly into your code without going through a ROS2 component.

For more documentation on how to install and use this component, refer to the documentation of the apriltag_detector package.

Components

apriltag_detector_umich::Component

  • Topics (subscribed, but ONLY when there is a subscriber to tags):

    • image: image topic to use.

    • tags: the detected tags from the apriltag library.

  • Topics (published):

    • tags: tag detections.

  • Parameters:

    • blur: Sigma (in pixels) for gaussian blur. Default: 0 (no blur).

    • decimate_factor: Decimate image by this amount. Factor 2 will decimate by 2 in both directions. Default: 1 (no decimation).

    • image_qos_profile: QoS profile for image subscription. Allowed values: default, sensor_data. Use this parameter to achieve QoS compatibility when subscribing to image data. Defaults to default.

    • image_transport: The type of image transport to use, e.g. compressed. Default: raw.

    • max_allowed_hamming_distance: discard tags with hamming error larger than this. Default: 0 (no error allowed).

    • num_threads: number of threads to use for processing. Default: 1.

    • tag_family: Apriltag family. Allowed values: tf16h5, tf25h9, tf36h11, tfCircle21h7, tfCircle49h12, tfStandard41h12, tfStandard52h13, tfCustom48h12. Default: tf36h11

License

This software is issued under the Apache License Version 2.0.