zapriltag_ros

​ This package provides the zapriltag_ros node, which detects april tag and provide the 6-DOF pose estimation. The detection can be stopped at any time.

Compile & Dependency&Usage

​ This package depends on apriltag, OpenCV. After apriltag and OpenCV were installed, clone this repositery and compile it by catkin_make.

• install apriltag by cmake

git clone https://github.com/AprilRobotics/apriltag.git
cd apriltag
cmake .
sudo make install
cd ..
sudo rm -rf apriltag

• Usage

  roslaunch zapriltag_ros zapriltag_ros.launch
  

Subscribed Topics

​ Currently, this package only subscribes

​ /camera/color/image_raw (sensor_msgs/Image)

Published Topics

• Custom message

​ The pose estimation results is published as a custom msg (see msg/TagDetecion_msg.msg)

​ TagsDetected (zapriltag_ros/TagDetection_msg.msg)

• Official message

  If the parameter publish_tf is set as true, also publish a tf whose child_frame_id

  named as tag* where * means id

Parameters

​ The parameters used are stored at the config/zapriltag.yaml. Check for further information.

• ~intrinsic parameter

  intrinsic parameter contains fx,fy,u0,v0

• ~quad_decimate

  Decimate input image by this factor.

• ~quad_sigma

  Apply low-pass blur to input; negative sharpens

• ~nthreads

  Use this many CPU threads

• ~refine_edges

  True for spending more time trying to align edges of tags

• ~tag_family_name:

  Name of tag family to use. Options have tag36h11, tag16h5,tagCircle21h7,tagCircle49h12,tagStandard41h12,tagStandard52h13,tagCustom48h12

• ~tag_size

  The physic size of tag, unite: meter

• ~tagDetectorOn/tagGraphOn/colorOn

  Use at any time by ros::param::set("zapriltag_ros/tagDetectorOn",false)to activate or stop detection/detection result display/image display.

• ~publish_tf

  True for publishing tf. It can be stopped by ros::param::set("zapriltag_ros/publish_tf",false) at any time

Tips

If the TagDetection_msg is needed at other packages. Modify your CmakeList and package.xml to add

find_package(catkin REQUIRED COMPONENTS
  zapriltag_ros
)

#in case of could not find zapriltag_ros/TagDetecion_msg.h error
add_dependencies(*** zapriltag_ros_gencpp) 

<build_depend>zapriltag_ros</build_depend>
<run_depend>zapriltag_ros</run_depend>